Updated CyMAC measurement, comparing 260 hrs of measurement time vs. 405 hrs.

[Ma, Tyler, Christina]

This past week, we were able to set up the data streaming for continuous acquisition to the PCs, and can conduct the initial tests now. We were able to do this by:

• Installing the correct OS ecosystems to each Red Pitaya
• Installing the terminal streaming client
• Debugging formatting and file saving issues by saving the data in a TDMS file on the host PC.

Date and Time: Around 4:20 PM on Auguest 6, 2025

Location and Temperature:

• Back of the room 1119, around the working station: 90.2 °F
• Front of the room 1119, around the doorway: 85.8 °F
• Back of the room 1129, around the working station: 93.4 °F
• Front of the room 1119, around the doorway: 82.3 °F
• In the hallway in front of room 1119: 77.2 °F

Simulating how point absorber defects on Advanced LIGO mirrors affect cavity performance by modeling a 4km LIGO-like arm cavity with a point absorber fixed at 5cm off-center on the ITM. In this simulation, displaced the laser beam across a 21×21 grid while calculating the deformation, then measuring the resulting power loss in the cavity (~283W circulating power).

[Tyler, Ma, Christina, Maple, Cece, Mary, Pooyan, Audrey]

We started by cleaning outside of the cleanroom wiping down the cable channel and working our way down while taking the pre-cleaning measurement. We then stated wiping down the inside of clean room and vacuumed, mopped the outside of the cleanroom. Finally, we vacuumed, mopped, and wiped down the floor inside the cleanroom.

Particle Count Measurements:

• Pre-cleaning (2:00 pm):
  • Zone 3:
    • 0.3 µm: 2707
    • 0.5 µm: 1374
    • 1.0 µm: 249
  • Zone 4:
    • 0.3 µm: 2207
    • 0.5 µm: 1166
    • 1.0 µm: 374

• Post-cleaning (4:30 pm):
  • Zone 3:
    • 0.3 µm: 4082
    • 0.5 µm: 2415
    • 1.0 µm: 708
  • Zone 4:
    • 0.3 µm: 1707
    • 0.5 µm: 791
    • 1.0 µm: 416

[Ma, Christina, Tyler]

ADC CyMAC 260 hr, 8192Hz sampling rate channels V3 and Vref6

[Ma, Christina, Tyler]

Figure 1 shows the following PSDs for channels 0-15 from the 14 hour test. Figure 2 shows the reduced chi squared and CSD plots for both the 2 Hz and 16 Hz resolutions.

Date and Time: Around 4:50 PM on July 1, 2025

Location and Temperature:

• Back of the room 1119, around the working station: 85.7 °F
• Front of the room 1119, around the doorway: 83.5 °F
• Back of the room 1129, around the working station: 79.1 °F
• In the hallway in front of room 1119: 76.5 °F

[Christina, Ma, Tyler]

Yesterday, Ma and I started taking data for the PSD/CSD measurements while the photodetectors and one of the heater elements are on (8) and are using the Red Pitaya to compare it to the data we took for the same measurements on the CyMAC. It will be finished Wednesday morning, and then we plan on starting to take additional recordings in order to conduct the same type of comparison for the dark noise measurements.

I've been looking into the performances of individual channels on the Cymac by computing their individual PSDs and corresponding CSDs that show their noise relation to each other. It appears some channels do have lower noise floors than others, and some combinations of these actually do perform similar to the Red Pitaya (showing below the CSD between CHs 3 and 5), although it doesn't look like it's much of an improvement. The best method as of now still appears to be phase-locking two separate ADCs to reduce the correlated noise floor further.

This can be further discussed at the July 22, 2025 group meeting.

[Luke, Luis]

We’ve been looking into methods for evaluating the performance of the HEPA filters in the clean room. Measuring flow rate appears to be a promising approach, since the filter manual specifies a recommended minimum of 70 ft/min.

At the moment, we don’t have a flow rate measurement device on hand. We're currently looking into two options:

• A standard vane-style anemometer, which is more affordable but may lack sensitivity near the minimum required flow rate.
• A hot-wire anemometer, which offers better resolution and accuracy at lower speeds, though it's more expensive.

In the next few days, either Luis or I will contact Terra Universal to see if they have any measurement solutions that would integrate well with our clean room setup, or if they can recommend best practices for verifying HEPA performance.

[Christina, Ma, Tyler]

Pomona Box completed and is now on the server rack in 1119. Additionally, the photodetectors were connected to the box and set up in front of the heater elements.

Below is attached the ADC noise floor of two CyMAC channels vs the Red Pitaya.

The frequency resolution of these RIN spectra are 16 Hz, with N_meas = 19,308,426 for the CyMAC, and N_meas = 263,024.

After acquiring some new equipment for the labs, a few of us spent time on Thursday and Friday sorting through everything and storing them into their appropriate places. New vacuum parts, power supplies, cables, and much more were included. The rooms are now ready for the lab tours commencing Tuesday afternoon.

Below are the drawings for the pomona box modifications

Slides

Slides

[Ma, Tyler, Christina]

Finished external reconstruction of the FROSTI by installing all the pins to the 2 DB 25 connectors. To ensure everything was operating correctly, we did electrical testing by testing continuity and by checking each of the heater elements' RTD and power resistance values and comparing them to what was tabulated in January. Additionally, we organized the wires and added the stands.

[Tyler, Ma, Christina, Luke]

We threaded the wiring of the heater elements through the reflective surfaces and were able to attach each piece with the Macor spacers and connect both sides. We used the guide rails and screws to ensure proper alignment. The only necessary step left is to add the additional external screws for the reconstruction.

[Luke, Luis, Tyler, Ma, Christina, Maple]

We started by cleaning outside of the cleanroom wiping down the cable channel and working our way down. We replaced the air filter in the HEPA filter with what seemed to be the last one in storage. We then vacuumed outside, before wiping down the inside of the cleanroom. We then vacuumed, mopped, and wiped down the floor inside the cleanroom.

We are ready for venting the vacuum chamber which is planned to take place 6/26/25 at 10am. 

Particle Count Measurements:

• Pre-cleaning (12:00 pm):
  • Zone 3:
    • 0.3 µm: 2517
    • 0.5 µm: 662
    • 1.0 µm: 176
  • Zone 4:
    • 0.3 µm: 177
    • 0.5 µm: 44
    • 1.0 µm: 0

• Post-cleaning (1:45 pm):
  • Zone 3:
    • 0.3 µm: 619
    • 0.5 µm: 88
    • 1.0 µm: 0
  • Zone 4:
    • 0.3 µm: 177
    • 0.5 µm: 88
    • 1.0 µm: 0

Updated ADC noise spectra measurements using diaggui.

NOTE: Will update plots with proper axes

CYMAC Remote Control Cable Assembly

Cable Functions

The custom cable assembly serves two primary functions:

Note: All connections are verified with a multimeter.

Note: This cable allows remote control of the Sorensen power supply with an external voltage source (Cymac DAC).

Note: For more details, check section 2.11.1 from the attached Sorensen power supply manual.

• Hosted Lukes model on Chimay. It's available at https://richardsonlab.ucr.edu/real-time-frosti
• The sourcecode is at Github. It is clones at /var/www/html/real-time-frosti, and this is the block added to nginx config file at /etc/nginx/sites-available/default :
  
  location /real-time-frosti {

root /var/www/html;
index index.html index.htm index.php;
}
• Also added this line to the crontab, so the code will be checked for updated from the sourcecode every five minutes. 
  
  */5 * * * * cd /var/www/html/real-time-frosti/ && git pull 
  
  
• TODO: Move the sourcecode from Github to git.ligo.org, and make the repository public. 

• Fast channels recorded to .gwf frame files
  • Had to add a DAQ Channels block to the c1msc model for those channel to be recorded in the .gwf frame files. The block is in the CDS_PARTS, and I just had to copy it to our model. Here is the example text for the channels:
    
    

    #DAQ Channels

    ONE_DAQ_CHANNEL 2048
ANOTHER_DAQ_CHANNEL 1024
SCIENCE_FRAME_CHAN* 1024
UINT32_CHAN uint32 2048
DAQ_CHANNEL_AT_DEFAULT_RATE

    I added two channels to the list (V0 and V1). Remember that the channel name should not be the full name, but just the part's name. In this case, I added these two channel names:
    
    V0_OUT
V1_OUT
    
    with the default sample rate. 
• The fast channels are recorded with an extra _DQ in their names. So, in ndscope and diaggui these two channels should be addressed as
  • C1:MSC-V0_OUT_DQ
  • C1:MSC-V1_OUT_DQ

• Update 6/13: enabled recording of all the ADC voltage channels so that Tyler can use all the data for the noise floor calculation. attached is an example of diagggui with almost 30 hrs of data.

• TODO: Enable daqd_wiper

By measuring the resistance of the ladder, I obtained a graph of resistance as a function of voltage.
All the heater elements behave consistently, showing only a small standard deviation.
However, heater element 5 shows a significantly larger standard deviation.
Upon examining the initial ladder graph, I noticed that the resistance of heater element 5 increases following a power outage that resets the system.
At this point, I am unsure why this behavior occurs.

• The MEDM models issue was fixed. The issue was that building the c1msc model alone was not enough and we had to re-build the c1iop as well, although no changes has been made to the c1iop. Added a note in the wiki on this for future reference.
• For writing the fast channels to the frame files, our CDS system should have a GDS broadcaster. I followed this wiki page to set one, but it breaks the current daqd system. Asked about it earlier today on the CDS Mattermost channel and waiting for a response. 
• Maybe I should continue the distributed scheme we have been trying for the nds2-server and let another machine on the network do this. 
• Question: daqd has a feature to zero-out the bad data (NaNs), and it is currently on for our system. I don't think that it's a good idea to have this. Should I turn it off? 

Date and Time: Around 3:50 PM on June 2, 2025

Location and Temperature:

• Back of the room 1119, around the working station: 86 °F
• Front of the room 1119, around the doorway: 84.1 °F
• Back of the room 1129, around the working station: 78.6 °F
• Front of the room 1129, around the doorway: 78.3 °F
• In the hallway in front of room 1119: 75.2 °F

We currently have the parts for a DB9 connector but need parts for a DB25 connector, where did we get the parts for the DB9 connector? We may be able to use the same company for the DB25 connector.

Also need a cable for the connectors. Find a DB9 to DB9 cable in 1129, not sure if I can disassemble it and use just the cable.

The pressure in the vacuum chamber rises to 2.12e-8 torr, which needs baking.

There are three major issues with the lab's CDS system that should be addressed. They are ordered from the highest priority to the lowest.

• CyMAC has stopped serving the fast channels (65k Hz)
  The channels are still there, and the data from the slow (16 Hz) channels is served correctly, but the fast data is not served. As a result, diagggui can not retrieve any information at the moment.
  Probably the issue is the same as the version conflict between daqd and nds2-server. After installing nds2-server on CyMAC and realizing that the conflict can not be resolved, I reverted the changes so that the CyMAC could be compatible with daqd, but there is a chance that there are still version conflicts that block the fast channels.
  I suspect that we have broken the MSC model when adding the new button. This could explain both the fasr-channels fault and the unexpected crashes.
  
  UPDATE 6/5
  Fixes this by rebuilding the models.
  Note for the future: The c1iop and c1msc models should be rebuilt together, even if no change has been made to c1iop.
• The fast channels were not saved to the frames
  Reviewing the frame files showed that the daqd was only saving the 16 Hz data in the .gwf frame files. I had missed this because I only checked the existence and the integrity of the raw frame files, but never retrieved the high-frequency data itself to check it.
• NDS2-server is installed, but does not distribute the data
  I managed to install the nds2-server and its satellite programs on the Chimay, and NFS mount the frame files on it. The server successfully chaches the channel names, frame files, and the data, but fails to list the channels for distribution.

Note: CyMAC machine was strangely disconnected from the network, and required manual reboot. I couldn't find any abnormal logs that could explain what happened.

Slides

I have added some slides to my meeting updates. The updates include: my choice in position and width, some figures I have added to my write up, and what I think my immediate steps are to wrap up.

I have also made a new FROSTI model that conducts its raytracing in real time. Something that was severely lacking in the previous model.

Using the configuration in section 2.11.1 in the Sorensen installation and operation manual (attached below), I'm able to remote control the Sorensen power supply.

I use DAC VEXC8 as the external voltage source and a breakout board to match the configuration of connector J3.

I have recorded 7 cycles (attached below), and am now working on analyzing the data.

slideshow

Slides

Date and Time: Around 2:20 PM on May 21, 2025

Location and Temperature:

• Back of the room, around the working station: 85.5 °F
• Front of the room, around the doorway: 82.3 °F

All Sorensen power supplies are turned off. The Cymac system is down (All Chassis are down)

If you need more information or if you need to turn them back on please contact Xuesi Ma.

Slides

I have re-run the optimization plots with the changes mentioned last week. 

I have added the heat maps of the HOM scattering from HR deformation and the HOM scattering due to the OPD difference as well as the curvature actuation of the surface. 

[Luke, Mohak, Luis]

We were also able to remove the residue that has built up on the soft walls by donning a skinny bunny suit and with two wipes rubbing both sides of the soft walls at the same time. The wipes would get gummy very quickly and need to be replaced frequently.

Particle Count Measurements:

• Pre-cleaning (1:20 pm):
  • Zone 3:
    • 0.3 µm: 3577
    • 0.5 µm: 1369
    • 1.0 µm: 485
  • Zone 4:
    • 0.3 µm: 1062
    • 0.5 µm: 442
    • 1.0 µm: 177

• Started Cleaning (3:00 pm)
• Finished Cleaning (4:00 pm)

• Post-cleaning (4:22 pm):
  • Zone 3:
    • 0.3 µm: 3577
    • 0.5 µm: 618
    • 1.0 µm: 132
  • Zone 4:
    • 0.3 µm: 2031
    • 0.5 µm: 397
    • 1.0 µm: 132

[Ma, Luis]

After taking the RGA scans of the new system, here are the results of the raw and normalized data.We can see that in the post baked system the He peak is way lower, and the peaks around 20AMU are also significantly lower.

Slides

I have changed some properties of the thermal model and am re-running the thermal sweeping

I have also been messing around with making a logo

The vacuum chamber has stopped baking. 

Current state as of 12:30, 5/2/2025:

The gate valve is open, and the filament of the RGA is on.

The temperatures were steady at:

PID right: barrel upper: 108°C,  RGA volume: 120°C

PID left: barrel lower: 120°C, Lid: 91°C

[Luke, Ma, Tyler]

The vacuum chamber is currently baking. 

Current state as of 5:00

The gate valve is open, and the filament of the RGA is on. Argon leak is opened

The temperatures are as follows:

PID right barrel upper: 99°C,  RGA volume: 120°C

PID left barrel lower: 123°C, Lid: 92°C

[Ma, Luke, Luis]

April 29, 2025

3:30 PM
We performed another leak test on the vacuum system, this time focusing on the welds around the main cylinder. The leaks from these junctions were in the mid 10⁻¹¹ range, but we noticed some strange behavior after completing the test. The partial pressure of He kept rising at a slow, constant rate for a while—even after stopping the test for about 15–20 minutes and restarting the measurement. We're not sure what’s causing this and wanted to check in before moving forward with the bake.

4:30 PM
We performed an RGA of the system (see below) and the findings are that there was a higher contraction of He than usual. We have attached another scan from 2/24/25 for reference.

5:00 PM
We turned off the electron multiplier and closed the RGA Program.

[Ma, Luke, Luis]

April 24, 2025

3:00 PM
Ma and Luis attempted to connect to the RGA to initialize the leak test but encountered some difficulties.

3:20 PM
After restarting both the computer and the RGA, we realized that the DB9 cable was not connected to Spica. After connecting it, we had no further issues communicating with the RGA.

3:30 PM
Luke and Luis performed the leak test. There were no significant leaks in the vacuum system. The highest leak rates we found are listed in the table below; the rest of the entries were limited by noise, as we could not detect any change in the program after spraying the ports with He.

I have created two more plots. One on the transmitted power for a specific configuration. This was done by taking the product of the efficiency and the power released by surface area of the source plane for a configuration assuming it is at 300C. The second is a plot of how close the reflector is to the test mass I have included a contour line at 2mm the nominal proximity constraint. Both of these plots are generated for a 2cm wide target plane.

Somethings of note: Because the proximity requires no modeling and can be determined purely mathematically it is easy to re-generate this plot of other target widths. If you increase the target width the proximity contour moves upward and downwards if reduced.

Test 7: Reconnect ribbon cables

• Setup: Reconnect all the ribbon cables, and turned on the AI Chassis while isolated rack
• Observation: No spike observed.

Test 8: Reconnect to rack

• Setup: Reconnect the AI Chassis to the rack.
• Observation: No spike observed.

Test 9: Restore to original position.

• Setup: CLose up the AI Chassis, and put it back to its original location.
• Observation: No spike observed.

I have redone the width and location optimization with a 40kg test mass. This was to see where the nominal ring heater would fall in this optimization map see attached.

There are two concerns I have with this modeling:

1. I am using normalized power only imparting 1W, which may effect the single pass scattering used for optimization.
2. I am only looking at the surface deformation and I believe that looking at OPD may also be something that is important to consider. 

Note z_RH is measured from the HR surface and w_RH is the half width of the target plane

Avoiding Thread Contention When Using Multiprocessing with Finesse and Cython

When running Monte Carlo simulations or other computational workloads, it's common to use Python's ProcessPoolExecutor to parallelize multiple independent tasks. This approach works well—until it interacts with low-level libraries that themselves use multi-threading under the hood.

The Problem: Thread Over-Subscription

In a recent project, I ran into a significant performance issue while executing a large number of Monte Carlo trials using a process pool with 30 worker processes on Megatron (with 48 cores). Each trial ran a function that internally used cython.parallel.prange for fast, element-wise operations, which is what Finesse uses under the hood for many internal numerical calculations. Cython, via OpenMP, was configured to use all available CPU threads per process by default.

This resulted in severe thread over-subscription. With 30 parallel processes and each process attempting to use all 48 threads, the system was launching over 1,400 threads concurrently. The CPU quickly became saturated, and the tasks stalled. In some cases, the system became unresponsive, and the jobs had to be canceled repeatedly.

This happens because when the function calls into these libraries from within a Python multiprocessing context, each subprocess will attempt to use the full number of threads available to the machine.

The Solution: Limit Threads per Process

The solution is simple: explicitly limit the number of threads each subprocess is allowed to use. This can be done by setting the environment variable at the top of your script, before importing any thread-hungry libraries like Finesse.

      
import os
os.environ["OMP_NUM_THREADS"] = "1"

    

By setting OMP_NUM_THREADS to "1", we ensure that each multiprocessing worker uses only one thread internally, preventing them from overloading the system and allowing the tasks to run more efficiently.

Test 4: AI Chassis ground isolation

• Setup: AI Chassis isolated from the ground with readout directly connected to adapter board
• Observation: No spike observed.

Test 5: Ribbon cable check

• Setup: AI Chassis remains isolated from the ground. The signal is measured after the ribbon cable. (Attachment 3)
• Observation: No spike observed.

Test 6: Single ground connection check

• Setup: AI chassis powered on but remains isolated from the frame. The signal is measured from the output of the AI Chassis. (Attachment 1 ,2)
• Observation: No spike observed.

Test 1: Adapter Board Connected to Filter Board

• Setup: AI Chassis is powered on. Signal is measured directly from the adapter board. All other ports on the adapter board are connected to the filter board.
• Observation: Two distinct spikes observed at the beginning of the measurement.

Test 2: Adapter Board Disconnected from Filter Board

• Setup: AI Chassis remains powered on. Signal is again measured directly from the adapter board. This time, the remaining ports on the adapter board are not connected to the filter board.
• Observation: Multiple spikes observed, distributed evenly across the entire measurement.

Test 3: Isolation Test with Spare Adapter Board (ongoing)

• Setup: Suspecting the original adapter board may be faulty, a spare adapter board is used for comparison. Signal is measured directly from this spare board.

Update, 04/08/25, Tue 17:30

Took the old adapter board out of the AI chassis and and used it to connect DAC to AA chassis. If no spikes are seen, it means that the glitches are not originating from this board.

Also checked al the previous spikes using the raw data (65536 Hz sample rate). The duration of the glitches are ~1 second, despite the previous guess that they are happening in the Milli-second scale.

The result from AI Chassis bypass test showed that the AI Chassis may be the problem. There are no spikes from DAC's direct output.

All chassis except timing chassis are turned off. Power supplies for 24V, 18V, and -18V are turned off

The AI chassis has been taken out of the rack for further inspection

https://dcc.ligo.org/LIGO-E2300117

https://dcc.ligo.org/cgi-bin/private/DocDB/ShowDocument?.submit=Identifier&docid=D2300124&version=

Upon final review of the FROSTI analysis included in the (hopefully) soon-to-be submitted instrument paper, I've made some adjustments to the reflectivity analysis that estimates the amount of power delivered to the test mass by the FROSTI. Initially, as detailed in elog 447, the delivered power was approximated to be 12.6 W (later adjusted to 12.9 W), with roughly 18% of this power being reflected by the test mass. After some final adjustments, this value now is closer to 12.0 W, with 10.2 W absorbed (15% power reflection). Below is a table showing the updated values for the FROSTI prototype tests:

Continue investigation in the spikes

Pulsed ADC with a function generator and find no spikes. Rules out ADC for causing the spikes

Loopback test that bypasses the FROSTI Chassis shows spikes (spikes happened on all channels at the same time)

Next step is to bypass the AI Chassis to find the source of the spikes

[Shane, Jon]

[Shane, Jon]

Update on the serial interfacing with the vacuum system: both turbo pumps are now able to successfully communicate through the code. The older pump, for unknown reasons, required a newer version of the communication syntax (despite the newer, small pump being able to communicate fine with the old communication format). We have also confirmed that the newer pump works with this new format as well. Next step is interfacing the pressure gauge.

Spikes Appear Again, need to address it systematically.

Power on and off before reaching steady state ✔

At 12V, the rise and fall time of heater elements are different from 24V.

Initial guess is due to temperature in the chamber. However, it does not seem to be the case, 24V with 30c have the same hall time as 24V at lower temperature.

Attached are some graphs for rise and fall time

After a weekend of powering on, the main chamber pressure stabilized in the UHV region.

Temperature in the chamber seems also not to change.

1424564097.243212 2025/02/26 00:14:39 UTC Time start

12V 2A right after start all 8 elements

1424564478.079428 2025/02/26 00:21:00 UTC Time stop

12V 1.8A right before stop all 8 elements

1424564832.211584 2025/02/26 00:26:54 UTC Time start

12V 1.9A right after start all 8 elements

1424565208.359935 2025/02/26 00:33:10 UTC Time stop

12V 1.8A right before stop all 8 elements

1424565573.565066 2025/02/26 00:39:15 UTC Time start

12V 1.8A right after start all 8 elements

1424565931.242394 2025/02/26 00:45:13 UTC Time stop

12V 1.7A right before stop all 8 elements

1424566292.67104 2025/02/26 00:51:14 UTC Time start

12V 1.8A right after start all 8 elements

1424566648.619952 2025/02/26 00:57:10 UTC Time stop

12V 1.7A right before stop all 8 elements

1424566996.312246 2025/02/26 01:02:58 UTC Time start

12V 1.8A right after start all 8 elements

1424567381.748943 2025/02/26 01:09:23 UTC Time stop

12V 1.7A right before stop all 8 elements

1424567756.528736 2025/02/26 01:15:38 UTC Time start

12V 1.7A right after start all 8 elements

0.2A right before start

spikes!?

1424643001.864687 2025/02/26 22:09:43 UTC

change c_0(VEXC0 & VCXC0) to 2V (why is it on 5V ?)

2025/02/26 22:18:51 UTC

Main chamber pressure:5.92e-9

RGA chamber pressure:1.98e-9

1424650528.240947 2025/02/27 00:15:10 UTC Time start (increase voltage)

24V 2.1A right after start all 8 elements

disconnect and reconnect (exc 1-4)(out 9-12) & (exc 5-8)(out 13-16)

2025/02/27 19:34:26 UTC

Main chamber pressure:1.34e-8

RGA chamber pressure:4.33e-9

Main chamber temp: 29

RGA chamber temp:29

2025/02/28 18:02:29 UTC

Main chamber pressure:1.05e-8

RGA chamber pressure:3.53e-9

Main chamber temp: 29

RGA chamber temp:30

1424801097.374902 2025/02/28 18:04:39 UTC Time stop

24V 1.8A right before stop all 8 elements

0.1A right after stop

1424827460.71372 2025/03/01 01:24:02 UTC Time start

24V 2.9A right after start all 8 elements

0.1A right before start

2025/03/01 01:25:34 UTC

Main chamber pressure:5.98e-9

RGA chamber pressure:2.06e-9

Main chamber temp:27

RGA chamber temp:27

2025/03/03 20:28:03 UTC

Main chamber pressure:7.8e-9

RGA chamber pressure:2.64e-9

Main chamber temp:27

RGA chamber temp:27

1424039912.625576 2025/02/19 22:38:14 UTC Time start

24V 2.8A right after start all 8 elements

1424044804.902443 2025/02/19 23:59:46 UTC Time stop

24V 1.8A right before stop all 8 elements

0.1A right before start and right after stop

note: turned on briefly to check current right before stop

2/20 RGA Scan

spikes??

1424129207.857777 2025/02/20 23:26:29 UTC Time start

24V 2.9A right after start all 8 elements

1424140789.856096 2025/02/21 02:39:31 UTC Time stop

24V 1.7A right before stop all 8 elements

0.1A right before start and right after stop

2025/02/21 02:43:19 UTC

Main chamber pressure: 1.54e-8

RGA chamber pressure:5.06e-9

spikes are due to loose connection between connectors.

1424210410.173863 2025/02/21 21:59:52 UTC Time start

24V 2.9A right after start all 8 elements

1424218357.96404 2025/02/22 00:12:19 UTC Time stop

24V 1.7A right before stop all 8 elements

each elements: 0.3A (0.2A increment)(all)

0.1A right before start and right before stop

2/24 RGA Scan

1424467918.129082 2025/02/24 21:31:40 UTC Time start

12V 2A right after start all 8 elements

1424478936.635821 2025/02/25 00:35:18 UTC Time stop

12V 1.6A right before stop all 8 elements

each elements: 0.4A (0.2A increment)(all)

0.2A right before start

rise time: A(1-exp(-t/tau))+B

fall time: Aexp(-t/tau) +B

[Ma, Luis]

February 24, 2025 - 1:00PM

Ma performed an RGA scan with the vacuum system containing the heater elements. The results are attached below.

These are some plots:

The first shows the convergence of the 02 mode reducing the size of the mesh. The second shows the the numerical error of the zernike.

The first is found by sweeping a parameter that changes the size of the mesh. The HR surface was set to half a cm for all values.

The second by taking the inner product of a zernike mode with its self and calculating its deviation from pi for varying fineness of the mesh.

[Luke, Mary, Luis]

Particle Count Measurements:

• Pre-cleaning (8:40 am):
  • Zone 3:
    • 0.3 µm: 441
    • 0.5 µm: 44
    • 1.0 µm: 0
  • Zone 4:
    • 0.3 µm: 353
    • 0.5 µm: 176
    • 1.0 µm: 44

• Started Cleaning (3:16 pm)
• Finished Cleaning (4:10 pm)

• Post-cleaning (4:15 pm):
  • Zone 3:
    • 0.3 µm: 574
    • 0.5 µm: 265
    • 1.0 µm: 132
  • Zone 4:
    • 0.3 µm: 177
    • 0.5 µm: 44
    • 1.0 µm: 0

[Ma, Luis]

February 20, 2025 - 3:30 PM

Ma performed an RGA scan with the vacuum system containing the heater elements. The results are attached below.

As we can see, we are not yet under cleanliness standards. The passing threshold is 4 × 10⁻¹⁰, we are very close to it.

Debugging update for vac system serial communications: we were able to successfully connect the smaller turbo pump to the Varian (manufacturer) software today by plugging the controller db9 directly into spica, and verified that the pump was able to send and receive information. Still no success on communication with the larger pump via python serial code, though. Issue potentially lies in the pinout mapping of the connectors, as the pinouts we'd been using work successfully for the small pump which only requires 3 connections (RXD, TXD, GND), but the large pump may require more. Tried to test this on the big pump by keeping the pinout setup for the small pump, and incrementally adding the remaining 6 connections on a one to one scale (Pin 1 matched to Pin 1, etc) between the controller DB9 and the field DB9 connected to the IOLAN ethernet cable. After each new connection was added, I retried running the serial connection code. None of the additional connections yielded any results, and the large pump remained unable to connect through the code. Next step is further looking into documentation on the pinouts to see if the large pump requires a different connection setup than the small pump.

Below is a preview of the final RIN figure that will be included in the FROSTI instrument paper. A quick summary of what is shown below:

The original RIN CSD measurement is shown on the top panel in red. Frequency bins that exhibit external electronics noise (ex. ADC, photodetector noise, etc.) are identified and shaded in gray. These noisy bins are then excluded from the dataset before beginning the next step in the analysis process: rebinning. Here, the resolution of the spectrum can be changed by averaging frequency bins together within a specified interval, with the goal of pushing the measurement curve closer to the A+ requirement shown in the figure. For demonstration below, the spectrum goes from a resolution of ~0.93 Hz to 14.90 Hz.

https://docs.google.com/presentation/d/1WiV2VqS0BzXNCK6VYYQ-Ty8xlHnzXatQaFbMf1-0rsY/edit?usp=sharing

[Ma, Pooyan, Tyler]

On Friday, we connected the vacuum chamber with the Cymac.

Over the last couple weeks I have been working on finding the optimal position of the ringheater's thermal profile. 

Today I would like to give an update of where I am at and my next steps.

Using the python COMSOL interface I have been able to run and save deformation data sweeping through a great deal of potential combinations of widths and positions.

I then calculated their zernike coefficients and using a very simple "quality" function (02 - (40)*10 - (4-4)*10), where 02 stands for the zernike mode of quadratic deformation, I was able to generate a heat map of comparing the "quality" verses the width and position used. 

Seen below are four plots. The first is simply the 02 coefficient of the decomposition followed by the negative of 40 and 4-4 then the "quality."

This 'quality' function was an arbitrary choice on my part. I believe that my next step would either be defining a more useful function or using finesse to model the actual effects of this surface deformation.

[Luis, Luke, Ma]

February 12, 2025 - 4:00 PM

We performed an RGA scan with the vacuum system containing the heater elements. The results are attached below.

As we can see, we are not yet under cleanliness standards. The passing threshold is 4 × 10⁻¹⁰, and we are currently measuring nearly double this value. We will continue performing scans to monitor any changes in these readings.

[Luis]

Feb/11/25 9:30am

Pressure gages were connected.

[Luis, Ma]

Feb/10/25 4:00pm

Bake was stopped.

[Luke, Luis]

The vacuum chamber is currently baking. 

We stepped up to 120°C by increments of 30°C starting at 60°C. We took about an hour break at 90°C to let the temperatures equilibrate.  

Current state as of 12:20:

The gate valve is open, the calibrated Argon leak is open, and the filament of the RGA is on.

The temperatures are as follows:

PID right barrel upper: 113°C,  RGA volume: 120°C

PID left barrel lower: 121°C, Lid: 114°C

The lower temperatures should climb as the whole system heats up. 

[Ma]

changed all zip ties to peek zip ties, and grouped wires together. The setup is ready to go into the chamber.

[Luke, Cece, Luis]

Particle Count Measurements:

• Pre-cleaning (12:15 PM):
  • Zone 3:
    • 0.3 µm: 1325
    • 0.5 µm: 265
    • 1.0 µm: 0
  • Zone 4:
    • 0.3 µm: 618
    • 0.5 µm: 132
    • 1.0 µm: 44

• Started Cleaning (3:20 pm)
• Finished Cleaning (4:20 pm)

• Post-cleaning (4:35 PM):
  • Zone 3:
    • 0.3 µm: 1106
    • 0.5 µm: 221
    • 1.0 µm: 0
  • Zone 4:
    • 0.3 µm: 530
    • 0.5 µm: 44
    • 1.0 µm: 0

[Ma] Wed 1/29/2025

No short circuit between heater element ✓

No short circuit to ground on any pin ✓

No short circuit between connectors ✓

[Ma]

Installed all the pins to the peek DB 25 connectors

[Ma, Cece, Luke, Mary, Shane]

On Friday (Jan 24), we installed the heater elements on the stand. The heater elements are arranged from 1 to 8, oriented from right to left as shown in Attachment 1. Each wire has been labeled according to its corresponding element number and type (e.g., RTD connections, heater connections).

Note: We currently do not have enough PEEK zip ties, so standard zip ties have been used temporarily. These must be replaced with PEEK zip ties before the setup is placed in the vacuum chamber.

Here is a quick update on some of the things I have been working on regarding my project. 

On Tuesday (Jan 21), we took the FROSTI apart in front of a filming crew. It was a success! The footage is going to be used in an APS video detailing the experimental cosmology research conducted in the department.

The FROSTI reflectors, heater elements, and legs were all bagged separately and a currently being stored in the cleanroom. If you need to do any work in there, please be mindful of these parts. The elements are currently on the shelf above the optical table, and the reflectors are placed on the table in the back corner.

[Luke, Liu]

Over the winter break I have been working on this desmos toy model of the Frosti. There are still a few rough spots but I belive that it is a good visual representation of a 2D slice of the frosti. 

On Tuesday, we prepared the FROSTI for disassembly in anticipation of the APS filming that is set to take place in the labs. The FROSTI has been unbolted from the optical table in the cleanroom, with its wires weighted down and the majority of its screws removed to ensure an easy removal of the reflectors during the filming process.

Attached below are updated plots for the FROSTI RIN measurements for Jan 14 group meeting.

[Luke, Tyler, Cynthia, Shane, Michael]

Summary of Cleaning Activities:

We began cleaning Room 1119 at 2:00 PM.

At 2:30 PM, we moved to Room 1129 and continued cleaning.

Cleaning tasks included wiping down dust-collecting surfaces and vacuuming the floors.

Once the labs were clean, we proceeded to the cleanroom. 

• Wiping down surfaces and soft walls
• Vacuuming, mopping the floor, and finishing with IPA wipes

Particle Count Measurements:

• Pre-cleaning (2:30 PM):
  • Zone 3:
    • 0.3 µm: 973
    • 0.5 µm: 354
    • 1.0 µm: 132
  • Zone 4:
    • 0.3 µm: 486
    • 0.5 µm: 177
    • 1.0 µm: 0
• Post-cleaning (4:10 PM):
  • Zone 3:
    • 0.3 µm: 619
    • 0.5 µm: 132
    • 1.0 µm: 0
  • Zone 4:
    • 0.3 µm: 397
    • 0.5 µm: 0
    • 1.0 µm: 0

[Luis, Luke]

RGA Volume: T = 22°C, P = 2.10e-9 Torr
Main Volume: T = 21°C, P = 5.71e-9 Torr

Measurements of the current state of the vacuum systems were taken today, now that the system had reached UHV status, the results are attached bellow. The first plot overlays the data of the empty chamber taken on 12/16/24 before inserting the MR material, and the data of the system today, with the MR inside. The second plot displays the S/N Ratio of the system. The last plot displays the data of the system with the Ar leak open and closed. Notice that it is common for the Ar leak close data to fail due to the calculation of the gas flux per unit ion current, which is dependent on the Ar peak.

[Luis, Luke]

RGA Volume: T = 23°C, P = 3.0e-9 Torr
Main Volume: T = 22°C, P = 9.90e-9 Torr

After letting the vacuum cool down for a couple days, we reattached the magnets and sensors, then we performed a RGA scan of the vacuum system, now containing the MR sample. The results are attached below. Something to notice is that we are technically not under UHV, though Luke and I believe the reading of the sensor is not completely accurate since it was still coming to a steady state, further test will be performed when the physics building is open again.

The vacuum chamber has stopped baking. 

Current state as of 11:40, 12/19/2024:

The gate valve is open, and the filament of the RGA is on.

The temperatures were steady at:

PID right: barrel upper: 129°C,  RGA volume: 125°C

PID left: barrel lower: 125°C, Lid: 114°C

The RGA flange was 37°C

Cleanroom was 26°C

Note the upper barrel was very close to the emergency shut off temp of 130°C. In the future we may want to either rewire some of the heating tape or lower the set temperature of the right PID controller.

Luis and I are planning on taking an RGA scan of the MR on Sunday before the campus shuts down for the holidays.

I have begun the (hopefully) final RIN measurements at 3:30 PM today. If you need to go into the cleanroom at any time between now and Sunday (the 22nd), please do not touch the FROSTI, the Red Pitaya, the photodetectors, or any of the wiring.

[Luis]

The vacuum system is being baked. I disconnected the digital gages and the magnets, opened the Ar leak and started the bake by taking the temperature from 60C-90C-125C waiting about 15-20 minutes between each interval. The RGA electronics were left on since the temperature of the flange was 36.6C (bellow the 60C threshold)

[Luis, Luke]

The MR material was placed in the vacuum chamber following standard procedures to ensure the vacuum remained as clean as possible. During this process, we only opened the main volume while keeping the gate valve between the two volumes closed to maintain the UHV in the RGA section.

An RGA scan was taken before this process, this will be used to compare the state of the vacuum with the sample inside to determine whether the MR material is vacuum compatible.

[Luis]

RGA Volume: T = 23°C, P = 1.71e-9 Torr
Main Volume: T = 22°C, P = 5.71e-9 Torr

On 12/13 I took another RGA scan to verify the state of the vacuum system and to see whether the degassing of the filament had worked. The results of the scan shows that we did get an overall improvement of the noise levels, though we still have some peaks that are higher than the rest.

Also, while I was around, I transferred the Viton O-rings to a bag and labeled it properly. They are ready to be put into the clean room.

[Luis, Luke]

RGA Volume: T = 21°C, P = 1.74e-9 Torr
Main Volume: T = 22°C, P = 5.60e-9 Torr

We performed an RGA scan of the system. As we can see, we met cleanliness standards. The S/N ratio was roughly calculated and it is about 100. I will update the code to make this calculation and to have it displayed on the plot in the next scan we perform.

After this, we closed the RGA to the main volume valve, degassed the filament, and after the pressure came down to what it was initially, we reopened the valve. After the degassing, we took another scan. The overlaid plots are attached below.

The noise floor seemed to be about the same. I will take another scan tomorrow to verify whether it was the same or if the system just needed a little more time to be completely clean.

[Luis]

I rebooted Spica and I was able to connect the RGA again. After Connecting the RGA, I left the filament on.

Attached below are updated ASD plots for the FROSTI RIN measurements. The parameters set for this are the following:

• DFT Size (N): 16384
• Sampling Frequency (F_s): 7.629 kHz
• Resolution (F_s/N): 0.93
• CH0 DC Voltage w/FROSTI ON: 113.6 mV
• CH0 DC Voltage w/FROSTI OFF: -5.7 mV
• CH1 DC Voltage w/FROSTI ON: 113.0 mV
• CH1 DC Voltage w/FROSTI OFF: -5.7 mV

Each measurement was recorded over a roughly two-day period. Before each spectrum was computed, the time-series signals were AC-coupled (i.e. the DC offset was subtracted from the data). The low-pass filters are still attached for dark and light noise measurements. ADC noise is measured with two 50-ohm terminators attached to the Red Pitaya inputs rather than the IR photodetectors.

[Luis,Shane]

An RGA scan was taken on Dec 4th. The results are attached at the end of the e-log. As we can see, the scan results are under the allowed limits. After the scan, Shane and I worked on the vacuum connections. The filament was turned off, and the RGA was disconnected from Spica.

After we finished the tests, we reconnected the RGA and attempted to turn the filament back on. However, the program was unable to connect to the instrument. We checked for any loose connections but did not find anything. The RGA connection needs to be troubleshot and fixed.

[Luke, Luis]

We couldn't access the bake log on the wiki. (see attached) So we looked in the documentation provided on the DCC to find at what temperature to bake the Viton O-rings. We found that we should bake Viton at 180°C for 24 hours. 

So we sonic-washed the O-rings, dried them, and then put them in the oven set to the following:

100°C in 15 minutes

100°C for 30 minutes

180°C in 30 minutes

180°C for 24 hours

30°C in 2 hours

Other things of note:

We refilled the water container as it was running out.

The nitrogen used to dry the clean and baked objects is now critically low.

The helium used in leak testing is also quite low (~400 psi).

Regarding the vacuum chamber:

I reattached the pressure gauges to the chamber and gave them about an hour to stabilize. They read out main 8.7e-9, RGA 2.6e-9. Please note these pressures should lower more as we only stopped baking on Saturday afternoon. 

Update Slides

The vacuum chamber has stopped bakeing. 

Current state as of 12:10, 11/30/2024:

The gate valve is open, and the filament of the RGA is on.

The temperatures were steady at:

PID right: barrel upper: 128°C,  RGA volume: 125°C

PID left: barrel lower: 125°C, Lid: 113°C

The RGA flange was 38°C

Cleanroom was 26°C

[Luke, Luis]

The vacuum chamber is currently baking. 

We stepped up to 125°C by increments of 30°C starting at 60°C. Everything went fine. After about 20 minutes of the PID controllers being set to 125°C, the flange closest to the RGA was 38°C, so we left it connected. 

Current state as of 4:15:

The gate valve is open, and the filament of the RGA is on.

The temperatures are as follows:

PID right barrel upper: 105°C,  RGA volume: 125°C

PID left barrel lower: 125°C, Lid: 82°C

The lower temperatures should climb as the whole system heats up. 

I will come in Saturday afternoon to turn them off so that we can look at the pressures on Monday. 

I downgraded the Red Pitaya back to OS 2.00-18 due to runtime errors during measurement. Once I did this, the device appeared to work much better than it has the last few weeks. First, it appears we can actually see the cutoff of the added low-pass filters that were added in to the RIN setup. Second, there does appear to be a difference again between the FROSTI ON state versus the dark state (i.e. FROSTI OFF). A long measurement of the ADC noise floor in the current configuration still needs to be recorded, but it does appear that the recent highlighted issues with the Red Pitaya have been solved.

[Luke, Luis]

Update of current state of vacuum chamber

Current temp: 24°C

Current pressure: Main 1.77e-8, RGA 5.3e-9 [torr] (Gate valve open)

Summary of recent work-->

To try and reduce the leak in the turbo pump by reducing cross-connection, we replaced the copper gasket. This made no improvement to the leaks.

Initially: 1.9e-9 --->

Left side: 1.33e-9, Right side: 3.37e-9 (Gate valve open)

This is still a significant leak. We have tried to tighten the bolts further, but they are as tight as reasonably possible. 

Things of note: While examining the knife edges, we found some very slight imperfections on the reducing cross's flange as seen in 474. This could be the source of our leak. We have replaced this gasket 1-2 times already and consistently have a slight leak. This imperfection is on the right side of the flange, which would be consistent with the measurements above. 

Unless we want to use the liquid sealant or replace the gasket with an annealed gasket, we could try baking the system again, as this allowed us to reach UHV in the main volume before. It also allowed us to pass the RGA scan, which we are currently failing. (see attached)

[Luke, Luis]

After the gasket replacement performed on Monday (11/18/24) we let the vacuum pump down to UHV pressure for a couple days. Today (11/20/24) we measured the pressure to be 5.30*e^-9 with a temperature of 22C, and we performed a leak test and RGA Scan.

Here are the results:

Chamber temperature: 23C

Chamber Initial Pressure: ~1.8e-8 main, ~3.5e-8 rga

Did another leak test after monday's work to check how the seal was holding up initial leak was 5.5e-9. I then tried to tighten the bolts a bit more the leak rose to 1.9e-8 about a factor of 4 change.

I checked another flange to confirm that I was preforming the test properly. I measured the elbow to pressure sensor to be 2.2e-11 aproximatly what it was earlier in the month (1.9e-11). 

I ran another isolation test. It is still exponetial. Graph attached.

Thoughts:

I belive at this point that it is a knife edge issue when replacing the gasket I checked both flanges and the new gasket. The tp knife edge seemed perfectly fine, the gasket had very minor scratches, and the reducing cross had very small imperfections on its edge. 

We may want to try and use the liquid sealant or get annealed gaskets for 4.5"

[Luke, Luis, Michael]

cleaning cleanroom and particle count

• 8:30 am: started particle count
  • zone 3:
    • 0.3 u: 1195
    • 0.5 u: 177
    • 1.0 u: 132
• zone 4:
  • 0.3 u: 619
  • 0.5 u: 0
  • 1.0 u: 0
• 9:00 am: began surface check and wipedown, including softwalls
• 9:35 am: started vacuuming the floor
• 9:43 am: finished vacuuming the floor
• 9:45 am: started mopping the floor
• 9:55 am: finished mopping the floor
• 9:56 am: started cleaning the buckets
• 10:00 am: started mopping with IPA wipes
• 10:05 am: finished mopping with IPA wipes
• 10:20m: started particle count
  • zone 3:
    • 0.3 u: 2213
    • 0.5 u: 398
    • 1.0 u: 0
• zone 4:
  • 0.3 u: 1150
  • 0.5 u: 177
  • 1.0 u: 44

slides

We've added two low-pass filters in hopes of reducing any potential aliasing that may be introducing additional noise into the power spectra for the RIN measurements. It still looks like the noise levels are too high. Attached below are some recent measurements taken with the FROSTI powered on and off.

[Luis, Luke, Ma Michael]

The isolation test was conducted on the vacuum system. Every pump was turned off under vacuum, and pressure measurements were taken every minute for 15 minutes. The results are displayed in the sheet linked at the end of this report. The pressure of the main volume dropped very slowly.

The pressure of the RGA Volume dropped in an exponential manner. The test had to be paused at 11 minutes due to concerns about the pressure exceeding the lowest permitted level for the RGA filament.

After the ISO test was performed, we attempted to tighten the bolts of the small turbo pump on the RGA Volume. However, we noticed that the pressure had increased by nearly an order of magnitude, going from 3.27 × 10^-9 Torr to 1.45 × 10^-8 Torr when both volumes were separated. We conducted a leak test for that particular flange and found a concerning leak of 2.15 × 10^-8 Torr, which had previously been 1.9 × 10^-9 Torr. We believe the copper seal was damaged during the ISO test.

View the results sheet

[Luke, Luis]

On Friday, 11/1/24, the MR was unpackaged and cleaned under the flow bench. We noticed an ink stain on one of the corners of the material. After wiping it down with IPA and Vector Alpha wipes, the stain was removed. However, the material showed some wear.

After cleaning, we placed it in the bake station and applied a stainless steel baking protocol. On Tuesday, 11/4/24, the material was removed from the furnace and packaged in a static shielding bag. The MR was wrapped in Vector Alpha wipes.

The Red Pitaya ecosystem has been upgraded to OS 2.00-35, with a key feature being greater freedom in adjusting the sampling frequency for signal analysis. Before, decimation factors could only be applied if they were a power of 2 (i.e 2,4,8,16,...) up to 65536. Now, the factors can be any power of two up to 16, and any whole number greater than 16 up to 65536. Further information can be found here.

We replaced the 1A breaker in the timing chassis today with a 4A one, and tested that all is working well. The chassis successfully outputted the correct signal (image attached). The real time models have also been restarted and the CyMAC diagnostics screen is showing all green flags. Timing chassis has been closed up and reinstalled in the server rack.

PowerPoint slides new

PowerPoint slides older

[Luke, Luis, Mary, Ma]

On 10/22/24 Luke, Ma, Mary and myself ran a RGA scan, the results are displayed below. The overall pressure of the vacuum was 2.0e-8 and the temperature readings were 26C for the RGA and 25C for the main volume.

As we can see, the vacuum is passing cleanliness standards again.

[Luke, Luis, Mary, Ma]

On 10/22/24 Luke, Ma, Mary and myself ran a leak test, the results are displayed below. The overall pressure of the vacuum was 2.0e-8 and the temperature readings were 26C for the RGA and 25C for the main volume.

[Ma, Luis, Shane]

Working theory for the timing chassis issues had been that the 1A breaker was tripping and causing the failure of the Valon 5015 and 3010 to output the timing signal correctly. We just tried bypassing the breaker, running 6 V on the benchtop power supply (set the current limit to 1.5A), with the 5010 generating the sine wave to pass to the 3010. All worked correctly, and there were no issues. Square wave outputted by the 3010 was exactly as desired (image attached) at the correct frequency, and this confirms the issue was the breaker, not the valon 5015. Ready to go ahead with ordering a new replacement breaker.

The following figure displays data acquired on 10/09, and it shows that we are no longer below the cleanliness standard. Also, the system's pressure went up to 1.9x10^-8 Torr (approximately 7x10^-9 Torr previously). This might be due to a leak somewhere in the system. More tests will be performed later.

I conducted separate tests on the '5015' and '3010a'. When powered individually, the '5015' outputs a signal at 33.55 MHz with an amplitude of 608 mV. It draws 1 A of current from the power source. The input signal for the '3010a' is 33.54 MHz with an amplitude of 670 mV (peak-to-peak) and a 15 mV DC offset. The output signal from channel 1 is a 65.5 kHz square wave with an amplitude of 3.28 V. The '3010a' draws 0.1 A of current.

Both the '5015' and '3010a' work fine when powered separately. However, when both are powered together, the power source behaves as if there is a short circuit. The current theory is that the switch or breaker is tripping, as it has a 1 A current rating. Since the combined current demand of both devices exceeds 1 A, this may be causing the issue.

Slides for 10/16/2024 Group Meeting

I tried adjusting the gain settings on the photodetectors to check if this would help improve the RIN spectra measurements. Overall, it doesn't look like it does, and if anything, looks worse. I assume this is so because as the gain is lowered, the amount of detectable signal from the FROSTI becomes smaller and smaller.

cleaning cleanroom and particle count

• 12:25 pm: started particle count
  • zone 3:
    • 0.3 u: 4614
    • 0.5 u: 872
    • 1.0 u:83
• zone 4:
  • 0.3 u: 2411
  • 0.5 u: 415
  • 1.0 u: 83
• 12:48 pm: began surface check and wipedown, including softwalls
• 1:20 pm: started vacuuming the floor
• 1:30 pm: finished vacuuming the floor
• 1:34 pm: started mopping the floor
• 1:40 pm: finished mopping the floor
• 1:40 pm: started cleaning the buckets
• 1:42 pm: started mopping with IPA wipes
• 1:50 pm: finished mopping with IPA wipes
• 1:51 pm: changed sticky floor mats
• 3:44 pm: started particle count
  • zone 3:
    • 0.3 u: 3207
    • 0.5 u: 624
    • 1.0 u: 83
• zone 4:
  • 0.3 u: 916
  • 0.5 u: 83
  • 1.0 u: 0

Power point slides

Group Meeting slides for Non-deterministic Heater Response.

The following images compare the RGA scans from 9/23/24, after the first bake with the new vacuum system, with those from 3/14/24, after bake 12 with the old system.

The first image shows a graph of the raw data and includes the calibrated leak for both curves. As we can see, our new system meets LIGO standards of cleanliness.

The second graph contains the plot of the normalized data.

A quick update on the effective emissivity analysis for the CIT FROSTI testing:

I was able to (roughly) match the OPD data to a referenced COMSOL model, with an applied power of 12.6 W (as seen below). However, when changing the emissivity of the ETM in COMSOL, the dT profiles do not seem to change much. I am not sure as to why this is the case at the moment, and will continue to look further.

Additionally attached are the current RIN measurements of the FROSTI prototype. Shown is the PSDs of both channels, in reference to their individual backgrounds.

Ringheater Update

If the link does not work here is the file.

Below is the dark noise spectrum of the Red Pitaya, which was measured over the course of a weekend. Additionally, I have successfully measured a signal from the photodetectors with the FROSTI as the IR source, so it seems there shouldn't be any worry of these particular detectors not being feasible for the RIN measurement.

[Luis, Luke}

Three RGA scans were taken. The improvement in the amount of HC in the vacuum is visible across the different measurements. Images are attached.

I measured the temperature of the flanges and reconnected the RGA turning on its filament. I then turned off the PID controllers.

Here is a table that has the temperature of the different parts of the vacuum chamber.

One ongoing work is to make all lab machines automatically backed-up on Scribe on a daily basis. The updates should be boatable and stored for some time (potentially a few weeks) on Scribe. Making whole disk images has already been tried for some of the machines with no problems. (e.g., Cymac and WorkStations)

The same thing can not be done with Chimay though, as it currently has one huge RAID-controlled volume that stores all the information (OS, home directories, and NDS-downloaded data). Creating daily full disk images of such a system is not practical. 

Here is the plan we came up with to overcome this issue:

1. Create one full disk image of Chimay and store it on Scribe (it was already done)
2. Move the nds-downloaded raw data temporarily to Scribe and remove it from Chimay
3. Make another full disk image of Chimay
4. Burn this image to a single disk and boot chimay with it

5. Restore the rest of Chimay disks and move the NDS data back

    

On the weekend (Sat and Sun 9/7-8) I tried to execute these steps. There wasn't enough free space left on Scribe to move all the NDS data to it, so I stored part of this data temporarily on WS4. Then I also checked storage-consuming directories and, in one case, removed some non-important stored files. As there was no free space left on Scribe to execute step no. 3, I initiated storing the image on WS3. Unfortunately, a couple of different trials of the image-creation process failed as there was not enough free space on WS3 to accommodate Chiamy image as well. I was not able to reduce the image size such that it can be stored on WS3. 

These are the options left for us to get this work done. 

1. Distribute the NDS files between different machines to make enough free space on Scribe for the image and then follow the previous plan
2. Shrink the Chimay drive size, create the image and then follow the previous plan
3. Temporarily transfer some services to Megatrone (Network gateway, Wiki, elog) and recreate chimay and its services from scratch

On the 5th I had tried to start baking the vacuum chamber however certain parts of the chamber were getting too hot and causing the controllers to shut off. So I turned them off so that the next day I could rearrange the temperature probes. I then on the 6th set them up so that instead of overshooting the temperature they would be a little low in places.

After being left over night the cooler parts of the vacuum chamber got much closer to the desired temperature of 120C.

Here is a table of the temperatures of the sections of the chamber. Note: After these measurements were taken the PID controllers were set to 125C.

Here is a table of temperature of the flanges that have electronics.

Other temperatures of note:

The optical table was about 38C

The cleanroom was around 33C (~91F)

The timing chassis used for the cymac has been shut off due to an unknown issue causing its supplied current to fluctuate. All real-time models will be suspended until a solution is found.

[Luke, Tyler, Jon]

On the 3rd we set up the pid controllers for the heater tapes and after putting on the insulation we started heating them up. We first brought it to ~50C and let it stabilize, there was about a 6-7 degree difference between the RGA and the barrel temperature, with the barrel being higher. We then brought it to 60 then 70C it still maintained the slight difference between the RGA and barrel temperatures.

Here is a table of the temperatures of the flanges connected to electronics as I left it.

Notes: I removed the electronics from the pressure gauge (main volume) because while it was below the required threshold it was still quite high compared to the other flanges.

[Luke, Luis, Cinthia, Michal, Tyler]

On the 26th Cinthia, Michal, and I took off the insolation on the vacuum chamber and re-routed it to include the new RGA volume. 

The next day Luis and I finished up the last of the flanges to be attached. We attached the Pirani gauge with a conical reducing nipple to the 2.75" port on the vacuum chamber. We then preformed the Helium leak testing, both flanges were quite low the 2.75" flange had a leak of 1.68e-10 torr and the 1.33" flange of 5.5e-12 torr. The leak on the 1.33" flange was so low it was difficult to know how much of it was real and how much was just noise.

[Luke, Tyler]

On the 27th Tyler and I ran the RGA leak test again with the electron multiplier on. These were the leaks we measured. The chamber's overall pressure was at ~6e-8 torr. 

[Luke, Luis, Jon, Tyler]

On the 22nd Dr. Richardson showed Luis, Tyler and I how to preform a leak test with the RGA. We did the initiall test and found a few leaks two were particuarly bad highlighted in orenge below. To try and remidy this we planned on replacing the copper gaskests on the leaking flanges. We then began taking the two problem flanges off, but seven of the eight bolts holding on the turbo pump were over tightened and had seized. So after we got them off we postponed the rest of the work to the next day.

On the 23nd Luis and I reattached the badly leaking flanges with new copper gaskets. We then preformed the Helium leak test with the RGA. As seen in the table below we weren't able to majorly changed the leaks in the two flanges.

[Luis, Luke, Tyler]

Vacuum chamber parts were finally received and assembled. After whipping down the parts, the blank was removed from the reducing cross. Then, the zero-length reducer was attached. Lastly, we installed the T that had the argon leak and RGA. The final pump down showed signs of an improved seal since the pressure dropped quite fast. This pressure is well bellow the limit required to use the RGA, argon test leak could be performed some time next week.

I have begun moving parts into the cleanroom for the upcoming FROSTI RIN tests that will be conducted within the next few weeks. While waiting for the rest of the equipment to arrive to perform the full-scale tests, I have additionally moved the FROSTI under the shelf above the optical table, where it will stay for the meantime. As always, please use caution when in the cleanroom. Aside from the FROSTI, the IR photodetectors that will be used for the test are delicate and costly to replace.

For some preliminary tests, I moved the IR photodetectors outside of the cleanroom and onto the other optical table. The basic goal was to obtain a signal from both photodetectors. To achieve this, one of the heater cartridges used for early FLIR measurements months ago was hooked up to a power supply (PS). The PS was set to supply 0.20 A with a voltage of 2.8 V; the corresponding power is thus 0.56 W. With this, I was able to measure a signal using the Red Pitaya, the device that will be used for following RIN measurements.

The width and location of the measured in-air change in temperature profile has been determined to be 0.045m and 0.137m respectively. Subsequently, a fake irradiance profile was able to be generated that best resembled what the actual irradiance profile could be using this information for testing in COMSOL. The generated irradiance profile that output the most similar change in temperature profile as the measured in-air profile has been included as well as the change in temperature profile it produced on the blackbody screen "test mass" model in COMSOL.

We noticed that the RTD temperature readings given on the Cymac were off, and traced the issue to miscalibration in the relationship between the resistance and temperature of each RTD (Callendar-Van Dusen eqn). Below is the table of values inferred from independent measurements of temperature and resistance to rectify this problem. This data was then fitted to better determine the coefficients present in the temperature-resistance relation:

       R_0 (ohm)   Alpha    Beta

RTD 0   80.8674   0.001315   4.273e-6

RTD 1   79.5704   0.001887   3.7873e-6

RTD 2   81.7334   0.002014   2.1724e-6

RTD 3   74.3060   0.003677   3.6022e-8

RTD 4   81.1350   0.001761   2.3598e-6

RTD 5   77.9610   0.002423   -7.5192e-7

RTD 6   78.7980   0.001373   6.2909e-6

RTD 7   83.8616   0.001890   3.3529e-6

       R_0 (ohm)   Alpha (1/C)

RTD 0   79.3962   0.002031

RTD 1   78.2874   0.002530

RTD 2   80.9775   0.002381

RTD 3   74.2947   0.003684

RTD 4   80.3199   0.002157

RTD 5   78.2106   0.002297

RTD 6   76.6825   0.002438

RTD 7   82.6645   0.002458

Measurements taken can be found here. An uncertainty of 1 C was assumed for temperature.

Another re-fit, but this time the quadratic coefficient (beta) is set to 1.003e-6:

       R_0 (ohm)   Alpha (1/C)

RTD 0   79.7386   0.001863

RTD 1   78.6248   0.002359

RTD 2   81.3254   0.002211

RTD 3   74.6127   0.003509

RTD 4   80.6652   0.001988

RTD 5   78.5450   0.002127

RTD 6   77.0144   0.002268

RTD 7   83.0204   0.002288

Using the data taken during the FROSTI testing at Caltech, I attempted to find a better calibration of the RTD sensors, given our past issues with inaccurate readings. The fit parameters, alpha and beta, are still all different from the initial values given to us by Fralock (alpha = .003, beta = 1.003e-6, R_0 was not given), but the true values will differ based on factors such as part geometry.

Today I installed the second desktop workstation in 1129. The new machine is an Intel NUC13ANHi5, with a 12-Core Intel i5-1340P CPU, 32GB DDR4 RAM, and a 1TB SSD.

I loaded it with a fresh installation of Debian 12 and installed the LIGO CDS workstation (control room) tools. It is assigned the hostname ws4 and and the static IP address 192.168.1.19 on the local lab network. Like the other CDS workstations, there is just one user account accessible with the usual credentials.

The machine is fully set up and ready for use.

Today, I borrowed a bolt extractor drill bit from the machine shop to remove some stuck bolts from the zlr. Before starting, I laid down a sheet of aluminum foil on the work table and wiped down all the tools I was going to use. I began by drilling a small pilot hole and then enlarged it with a 5/32 drill bit. However, when I attempted to use the bolt extractor, it didn't grip the bolt effectively. Our bolts were too seized, causing the extractor bit to repeatedly slip instead of gaining traction.

Finished ADC-DAC loopback testing today (see attached xlsx file or access directly here). All looks well with the first 8 channels, with the gain hovering just under 2. Also edited c1msc model in simulink to add channels 7-15 (the last 8 channels), and changed the rate back to 64K. See image 1 for the updated c1msc model. The last 8 channels are also looking good and show no problems, with slightly more scattering for the gain, but all values very close to 2.

We also installed the new eight-channel Perle IOLAN SDS8 terminal server today. Image attached.

NOTE: When we were installing it, we noticed an energized wire dangling from the 24V power supply. Has since been fixed and put back into place.

Installed a Synology NAS server (Synology RackStation RS1221) in lab room 1129, with host name “scribe” and ip “192.168.1.17”. It is mounted on the rack and each of its 8 storage bays has a 2TB SSD disk. It will be used to set up automated backups of all the lab machines (e.g., chimay, logrus, megatron).

One shared storage is set on it with SHR-2 as its RAID type. It can tolerate the failure of two disks and has 10.4TB of total capacity. 

We can use both rsync and dd to create backups of the system. A suggested backup schedule could be daily rsync backups and bi-weekly disk snapshots using dd. 

Created a Google Slides presentation to summarize all the mirror surface map information that we use for simulating interferometers. 

A+ expected maps are based on correspondence with G. Billingsley. The estimate for the A+ ITMs will be to take the “as polished” data and add coating non-uniformity to it. (T2000398) Neither of these are scaled for the precise thickness of the Ti:Ge coatings.

Google Slides link: https://docs.google.com/presentation/d/1ge-ciAiEdNyyTvSShYdZz2JpACFRY2W3JDpxHRqMnOQ/edit?usp=sharing

This is to optimize the FROSTI heating profile for ETM, by minimizing the residual RMSE of the HR surface deformation after the beam size weighted curvature is removed by the current RH. The parameters of the profile being explored are the location, width, and total power for the Gaussian Annulus. As shown in the attached series of plots, the optimal location is 9.9 cm, with a width of 7.7 cm, and a total FROSTI power of 12.7 W (for 1 W of Gaussian beam absorption). The residual RMSE is 1.2 nm. About 0.5% of the FROSTI power is lost at the edges of the TM.

For comparison, without FROSTI, the residual RMSE after the beam size weighted curvature removed by the current RH is 44.5 nm. When the width of the Annulus is set to be 3 cm however, the residual RMS is 3.1 nm, with much smaller FROSTI power needed at 4.7 W, and less power loss at 0.02%.

After the feedback from last meeting and Liu's help narrowing down what I should do to improve the model. I made some changes: First with Liu's help I made the proportions of the test mass and ring heater much more reasonable and parametrized by constants. Second from Cao's paper "FROSTI Nonimaging Reflector Design" Liu showed me what I should do to define the elliptical mirrors. Third during Friday's modeling/programming meeting walked me through getting the different irradiance plots to work. 

[ Luke, Jon ]

Started work at 11:00

As mentioned in my previous post the RGA was not clearing the table because of a tilt in the cross. So I removed the 90 deg elbow, loosened the bolt securing the Tee to the ZLR, and removed the cross from the gate valve. I then spun around the Tee on the bottom so that the cal leak would be pointing in the right direction and connected the rotating 2.75" flange of the cross to the gate valve. I then added the small turbo pump to the top of the cross. 

Then with the help of Dr. Richardson, we made some adjustments to how the Tee was oriented with respect to the cross and how the cross was with respect to the table. So that the cal leak and RGA would fit on the table. After that we made some changes to the bolting of the ZLR to reducing cross replacing the 2.00" bolts and nuts with 1.75" bolts and nut plates. We did face some difficulty with half of the 2.00" bolts which required a bit of torque to get them out. 

Finished work at 2:20 

Things to do:

Before we start pumping down the system again Dr. Richardson wanted two other changes to be made. To replace the 2.75" to 1.33" conical reducer with a zero length reducer. He also wants the bolts that hold the main turbo pump to be replaced with nut plates. 

I plan on starting this work on Friday (7/12) before pumping down over the weekend

[ Luke, Cynthia, Michael, Xuesi, Anthony ]

Started work around 12:45

We vented the chamber first and once it reached atmospheric pressure we started taking apart the RGA line.

We removed the parts in this order: Calibrated leak, RGA, Pressure gauge, 2.75" Blank on Tee, 2.75" Tee, all 1.33" Blanks on the cube, 4.5" feed through port, and finally the cube. Everything went smoothly after every part was taken off we covered the ends in Aluminum foil to maintain cleanliness. 

We then started the assembly of the new line. The parts were added in this order: Reducing cross, ZLR, Tee, Cal leak, RGA, 90 deg Elbow, and Pressure sensor.

We left off the Turbo pump as of now because we weren't able to find a 1" post not in use and we didn't want to put too much weight on the cross. We also noticed that the RGA might not fit on its probes because of a slight tilt to the cross and by extension the Tee. If this ends up being a problem we might need to remove all the parts connected to the cross so that we can reposition it so that the 2.75" rotating flange is connected to the gate valve.

Ended work around 4:00

After taking data for each of the individual heater elements, I imported them into python and overlayed them to produce an average temperature profile. I rotated the 7 of the elements to align with element 1's profile and averaged them out. By setting the range to 28C - 33C (this gave the best visibility of the heating pattern) it gave the profile attached.

For a quick projection for the resonant frequencies going from aLIGO to CE, the height and width of the BS are increased assuming the mass is increased from 14 kg to 70 kg, while keeping the aspect ratio fixed. The resonant frequencies for the two mechanical modes as a result becomes smaller, to 1.43 kHz and 2.11 kHz respectively, risking getting in the detection band.

Next step is to implement a mechanical ring with high stiffness outside the BS barrel to combat the decrement of the resonant frequencies of the relevant mechanical modes.

For this study, we looked at a simple case with an aLIGO-like test mass geometry (R=0.17m, H=0.2m) plus a barrel RH with 0.02m width at 0.03m from the AR surface with FEniCSx. The irradiance profiles are constant inside the width along the longitudinal direction, and zero outside the width. For the baseline non-astigmatic actuation with constant irradiance azimuthally. We have obtained roughly equal quadratic actuations along the x and y directions, as shown in figure. The total delivered power on the entire barrel is normalized to 1 W. The actuation on the curvature per power Delta S/Delta P in this non-astigmatic case thus is 0.835 uD/W.

For the astigmatic case however, the irradiance for the regions from one diagonal is increased by a given amount, compared to the non-astigmatic case, whereas for the other diagonal regions is decreased by the same amount (thus the total power is unchanged at 1 W). The HR deformation when the power is changed by 50%, for instance, is shown in picture, where the deformation along the x direction is larger than the y direction. The deformation in each direction however remains quadratic, with different curvature per powers for the x and y components, as shown in plot. The actuation on the curvature per power for an increasing amount of astigmatism is shown in plot. In terms of Zernike polynomials, the maximum amount of Z22 (astigmatism) for 1 W of total power is 2um while the remaining curvature content (Z20) is 6nm. This is shown in plot.

We will be configuring the RGA line to remove the spherical cube from the system. Currently our plan for the new design is to connect a 4.5" to 2.75" Reducing Cross to the gate valve on the vacuum system. It will be orientated vertically with the turbo pump on top coming off the end will be a 90 deg elbow. On the bottom there will be a 4.5" to 2.75" Zero length reducer attached to that will be a Tee on one side the pressure sensor and the other the RGA. Connected to the elbow will be the calibrated leak. 

The only parts not readily available are the ZLR and the 2.75" gaskets

We moved Frosti into the cleanroom and debugged it to make sure everything was working. One of the DB25 pins broke off at the connector for element 1 so it needed to be recrimped. Element 6 short circuited but fixed with adjustment to the heater power pin position. We connected the power and sensor connectors to the power box and recalibrated the RTD sensors.

Drawings and CAD models of the straight-edge designs are exported, and are visualized in SOLIDWORKS. Two are attached. One is a single edge of the evenly spaced polygon design with 16 edges, and the other is the 8x2 design, with two neighboring edges grouped together to replace the original single curved heater.

For the straight edge design in COMSOL, ray power detectors were placed at the heater's front surface. The irradiance is shown in figure. The amount of light rays deposited back to the heater is small when close to the center, where it is closer to the original ring. The ray power increases as we move further away from the center toward the edges. In addition, the total power integrated at the heater's front surfaces is about 21% of the original heater's emitted power. This could account for the power efficiency difference between the straight edge design and the ring design, as shown in plot for instance.

Set-up of the first CDS workstation for 1129, ws3, is complete and the machine is ready for use. The login credentials are the same as the other lab machines.

All that now remains is to install a permanent cable tray for running the new Ethernet cables between the electronics rack and bench (they are currently dangling from the suspended lights).

cleaning cleanroom and particle count

• 10:45 am: ran zero count test on particle counter
• 11:02 am: started particle count
  • zone 3:
    • 0.3 u: 3284
    • 0.5 u: 1247
    • 1.0 u:332
• zone 4:
  • 0.3 u: 1829
  • 0.5 u: 581
  • 1.0 u: 207
• 11:15 am: began hepavac of rest of lab
• 11:19 am: began surface check and wipedown, including softwalls
• 11:32 am: finished hepavac of rest of lab
• 11:35 am: started vacuuming the cleanroom floor
• 11:45 am: finished vacuuming the floor
• 11:47 am: started mopping the floor
• 11:55 am: finished mopping the floor
• 11:56 am: started cleaning the buckets
• 11:57 am: started mopping with IPA wipes
• 12:02 pm: finished mopping with IPA wipes
• 12:03 pm: changed sticky floor mats
• 12:04 pm: started particle count
  • zone 3:
    • 0.3 u: 3117
    • 0.5 u: 374
    • 1.0 u: 124
• zone 4:
  • 0.3 u: 4531
  • 0.5 u: 540
  • 1.0 u: 0

[Jon, Pooyan, Tyler]

A few computer machine changes have been made. 

• Logrus moved from 1119 to 1129. It is up and running with the same IP address as before. 
• A new Windows machine (host name: spica, IP:192.168.1.14) is installed in the 1119 server rack. It is connected to the RGA scanner with the serial port and is specifically used for that purpose. 
  • Update: The machine was off on 6/25, although it was left on 6/24. We think that it might have been because of Windows' default setting to suspend/hibernate the machine after idleness. To resolve this, I used  "powercfg /change" command to set all the following parameters equal to zero. The machine is still running on 6/26. 

    monitor-timeout-ac
    monitor-timeout-dc
    disk-timeout-ac
    disk-timeout-dc
    standby-timeout-ac
    standby-timeout-dc
    hibernate-timeout-ac
    hibernate-timeout-dc

• A new Debian machine (hostname: megatron, IP:192.168.1.16) is installed in the 1129 server rack. This machine is intended to be used for FEA/simulation work. A new 2TB WD Green SSD is used as its main disk drive. 

   At the moment, “controls” is the only user, and there are no apps/libraries installed on the machine.

  • Update: Jon installed LIGO cds-workstation tools and MiniConda on 6/26. 
  • Update: Pooyan and Liu set the following conda environments:
    • Env named “finesse” with Python 3.12.3 and Finesse version 3.0a24 installed. Finesse was installed via the source code. The subdirectory “/home/controls/packages” is used to store the package sourcecodes.
    • Env named “fenicsx” with the same version of Python and Finesse as the previous env, with the latest version of FEniCSx (0.8) and the test-mass-thermal-state installed.  

In the previous post, we saw that for the heater element design with straight edges in replacement of the current eight-element ring-like design, it provides the similar Gaussian-like irradiance profiles, but with smaller power delivery efficiencies, as shown in the plot. This turned out to result in similar but less prominent thermal effects.

They only differ from the original baseline design by a source power rescaling, however, as shown in the plot, where we see the power-rescaled irradiance profiles for the straight edge designs are close to that for the ring design. The resulting temperature profiles and thermal distortions are shown in plot and plot. The thermal effects for the 16 straight-edge design with renormalized source power for instance are strikingly similar to that for the original ring design.

An alternative straightened heater element design has also been investigated with COMSOL FEA simulation. As shown in the attached, in this new design each heater element component is cut with multiple straight edges but remains connected, shown in the same colors (green and red). In the example, four straight edges are cut from each of the four heater components (4x4=16 edges in total). There is no spacing between the neighboring edges from the same element component, but the edges from different components are separated by 2mm, as can be seen in the attached. This new N-in-one straight edge design offers similar irradiance compared to that for the evenly-spaced N-sided regular polygon straight edge design with the same number of edges, as shown in the plot. It however has fewer heater components, four in this case, which makes it easier to implement in assembly and wiring, and less vulnerable to electrical and thermal shorts with their fewer heater element pins.

I have been looking at the feasibility of an alternative heater element design for FROSTI that replaces the original ring-like heater elements with n rectangular elements with straight edges. They form an n-sided regular polygon that could well approximate the original annular ring if n is large enough. This eliminates curved surfaces requirement for the heater elements, which was the source of the many month production delay for the prototype parts.

This design was implemented in COMSOL, shown in the attached. From the face on view, each element has a trapezoid shape with straight edges. The edges between neighboring elements are parallel, with a space of 2 mm in between them.

The ray tracing and thermal analysis obtained from COMSOL are shown in the attached pdf.

In particular, the 2D irradiance profiles were obtained from the ray tracing (so far from the front heating surfaces only). The 1D radial profiles were integrated and shown in the attached. The power delivery efficiency for the original ring-like heater element design is integrated to be roughly 65%, for comparison. The plot also shows the radial irradiance profiles for three different straight-edge designs, which correspond to 16 edges, 18 edges, and 24 edges. We see that with the straight-edge designs, the irradiance profiles stay in a good Gaussian shape. In addition, with a larger number of edges, the power efficiency increases, but is always less than the case for the optimized ring-like design.

The thermal distortions for the TM were also obtained from COMSOL, using the irradiance profiles at the TM HR. As shown in the attached, with the straight-edge design, the effects on the thermal lens OPD and the HR surface deformation are similar to the ring design, but with less severe edge roll-off for instance.

Attached below are the initial results of the CIT FROSTI testing analysis.

Upon further inspection, one adjustment was made to the FROSTI profile analysis: changing the transmission value of the ZnSe viewport. It was initially assumed that the viewport possessed an AR coating, which would bring the transmission into the 90% range. Without the coating, it drops to roughly 70%. Assuming no coating, the estimated delivered power was calculated to be 11.7 W. This is consistent with the estimated power given from the Hartmann sensor analysis, thus it is believed that the viewport indeed had no coating.

cleaning cleanroom and particle count

• 1:45 pm: ran zero count test on particle counter
• 1:50 pm: started particle count
  • zone 3:
    • 0.3 u: 2660
    • 0.5 u: 332
    • 1.0 u: 41
• zone 4:
  • 0.3 u: 8106
  • 0.5 u: 2494
  • 1.0 u: 831
• 2:08 pm: began surface check and wipedown, including softwalls
• 2:22 pm: started vacuuming the floor
• 2:39 pm: finished vacuuming the floor
• 2:43 pm: started mopping the floor
• 2:53 pm: finished mopping the floor
• 2:54 pm: started cleaning the buckets
• 2:59 pm: started mopping with IPA wipes
• 3:06 pm: finished mopping with IPA wipes
• 3:10 pm: changed sticky floor mats
• 3:06 pm: started particle count
  • zone 3:
    • 0.3 u: 1496
    • 0.5 u: 83
    • 1.0 u: 0
• zone 4:
  • 0.3 u: 789
  • 0.5 u: 83
  • 1.0 u: 41

It should be noted that we can not have the zero length reducer and the gate valve on the same arm as they both have blind tapped holes. We need to decide if we want the gate valve or not as if we do, we will need to use the 3 inch long reducer.

Important Measurements:

From the back of the flange to the back of the RGA: 25.25 in

Height from bottom of the blank to the bottom of the chamber: 2.75 in

Some changes have been made to the FLIR readout code to help improve its functionality:

• More accurate temperature readings than before due to updates in the calculation procedure. A bug was causing one of the parameters to not update correctly; this is now fixed.
• Saved data now stored in HDF5 files rather than CSV.
• User can now enable automatic data storage by specifying a collection interval (in minutes). The choice of manually saving data is still present if desired.

Today the FROSTI RTD readout chassis underwent a redesign:

Instead of the original ratiometric method, which involved wiring the FROSTI RTDs in series, each element is individually powered by separate excitations. Each element additionally possesses its own reference resistor of 100 Ohm. Now, if an RTD experiences an electrical short, it should not affect the measurements of the others in sequence, as it had with the original design.

cleaning cleanroom and particle count

NOTE: particle counter was found dead, with the charging dock unplugged. For future reference, if you need to unplug the dock, please either plug it back in when you're done, or make a note in an elog so someone else can come down and charge it.

• 1:07 pm: ran zero count test on particle counter
• 1:26 pm: started particle count
  • zone 3:
    • 0.3 u:1787
    • 0.5 u:457
    • 1.0 u:41
• zone 4: We were only able to charge the particle counter a small amount before starting the cleaning, so it died again halfway through this measurement, and we didn't get results for zone 4. In interest of time, we just put it on the charger and started the cleaning.
• 1:49 pm: began surface check and wipedown, including softwalls
• 2:16 pm: started vacuuming the floor
• 2:24 pm: finished vacuuming the floor
• 2:26 pm: started mopping the floor
• 2:32 pm: finished mopping the floor
• 2:32 pm: started cleaning the buckets
• 2:35 pm: started mopping with IPA wipes
• 2:43 pm: finished mopping with IPA wipes
• 2:43 pm: changed sticky floor mats
• 2:45 pm: started particle count
  • zone 3:
    • 0.3 u: 1288
    • 0.5 u: 124
    • 1.0 u: 0
• zone 4:
  • 0.3 u: 415
  • 0.5 u: 290
  • 1.0 u: 0

Attached is a brief recap PDF file. A video file showing separate HOMs plots for the cavity scan with ETM08 surface map is also attached.

The codes are available at https://git.ligo.org/uc_riverside/hom-rh/-/tree/main/SIS

After meeting and discussing the current state of our work with Prof. Fulda a few weeks ago, we have decided that the best next step for the gtrace project is its integration into finesse work. Our first step towards this integration involved creating a sequential beam trace in contrast to the previous non sequential gtrace simulations. A sequential beam trace not only allows for faster runtimes of the simulation (<1 second) but also allows for more direct reading of certain beam parameters (beam size, gouy phase, and angle of incidence). The sequential model was created alongside a yaml output which provides values of parameters, now including the angle of incidence on a mirror.

Last Monday, Pooyan gave a report to the Cosmic Explorer optical design team on the current state of our project and the ultimate goal of our work. During the same meeting another group working in the optical design team presented their own work with gtrace and optical design, focusing more on optimization of parameters based on desired beam sizes at each mirror. It might be a good idea to begin attempting to bring our individual projects together to allow for collaboration and further developments.

Currently, only the crab1 layout has a sequential trace model. Pooyan is currently working on creating a finesse model for crab1 to serve as a proof of concept for how gtrace could be integrated with finesse by providing useful values such as angles of incidence.

[Jon, Pooyan]

Moved Chimay from the server rack in Physics 1119 to a new rack in Physics 1129. It is connected to the switch in that rack and has the same ip address as before.

All services are up and running.

It appears that JupyterHub creates some processes whenever a user connects to an instance of it, but in some cases does not stop those processes after the user is not using that instance. This results in having lots of running idle processes, each using a small bit of the resources. Those processes are killed now as a result of rebooting. It might be a good idea to manually restart JupyterHub (or the whole machine) every few months to avoid this.

Cleaned and baked the Cal Tech FROSTI legs and showed Luke the procedure on how to clean parts.

Upon finishing the FROSTI assembly last week, we ran into some electrical issues. An electrical short was found between two of the d-sub pins (2 and 8). It appears that the pins were somehow coming into contact with the aluminum surrounding them. This was causing the power supply to trip. The issue was seemingly fixed by adjusting the positioning of the cabling leading out of the reflector. When handling the device in the future, please make sure to keep the wiring as undisturbed as possible. The setup is rather fragile, and moving the cabling around could potentially reintroduce a short like this.

FROSTI assembly began today. After a final set of RGA scans were taken, the vacuum chamber was vented and the reflectors were removed. The chamber was then resealed and pumped down again. 

Today we completed the installation of the Macor hardware and heater elements between the two reflector halves. Tomorrow we will route, bundle, and terminate the power and sensor cables. 

FROSTI assembly was completed today. The RTD and power wires were terminated at the DB-25 connectors and the legs were put on. It is currently placed in front of the stand-in test mass (~5 cm away). The FLIR has also been moved back to it's nominal position. As of now, it appears there are some shorts within the power cabling. This will be a focus of tomorrow's work.

Heater 1= 73.6; 81.8

Heater 2= 70.4; 82.1

Heater 3= 71; 84.5

Heater 4= 71.5; 80

Heater 5= 70.5; 81.7

Heater 6= 72; 79.4

Heater 7= 69.2; 78.2

Heater 8= 71.1; 84.2

Heater 1= 72.8; 80.6

Heater 2= 69.5; 80.8

Heater 3= 70; 83.2

Heater 4= 70.6; 78.7

Heater 5= 69.9; 80.6

Heater 6= 71.1; 78.2

Heater 7= 68.5; 76.8

Heater 8= 70.1; 82.8

The FLIR and test mass stand-in have been transferred into the cleanroom. A software test will be run as soon as we get an ethernet cable long enough to reach into the cleanroom where the camera is set up. Once this is finished, the FLIR will be moved aside for construction of the FROSTI! When completed, the camera will be placed back into position for in-air optical testing.

Summary

Following Wednesday's cleanroom cleaning [333], we proceeded to vent the vacuum chamber, remove the heater elements and their mount structure, and install the FROSTI reflectors. The reflectors are the final components to undergo RGA testing before the FROSTI prototype can be assembled. After installing the reflectors, we pumped the chamber back down and initiated a 48-hour 125 C bake.

Vacuum Vent

At ~1:00 pm, we shut off power to all eight of the FROSTI heater elements. Prior to shutoff, all were operating in vacuum at roughly 300 C. We then waited approximately 30 minutes for the elements' temperatures to fall below 50 C.

At this point, we isolated the RGA volume from the main volume by closing both gate valves, leaving the RGA volume to continue to be pumped through the bypass line. We then backfilled the main volume via the needle valve connected to one of the 2.75" ports. Once the pressures had equalized, we removed the chamber lid via our usual procedure (requiring only a small amount of flathead-screwdriver prying) and extracted the heater element assembly.

Reflector Assembly

We then removed the FROSTI reflectors from their protective packaging (for the very first time) on the cleanroom tabletop. We tested the fit of the Macor and stainless steel hardware in the reflectors' tapped holes. The Macor standoffs and bolts appear to fit perfectly. However, the 1/4-20 tapped holes for joining the two reflector halves are too shallow by ~1/4". As a temporary fix, we used some on-hand stainless steel washers (which had already been cleaned and baked) to securely fasten the two halves together. In the final assembly we will replace these with slightly shorter 1/4-20 vented bolts.

Pumpdown and Bake

The two fastened reflector halves were placed inside the chamber, sitting on top of the two mounting legs (see attached photos). We then reinstalled the lid. In order to rough the main volume, we isolated the RGA volume from the pumpline (by closing the bypass line valve), shut down the pumps, and then backfilled the pumpline via the manual vent valve on the turbo pump.

Once the pressures had equalized, we opened the 6" gate valve separating the pumpline from the main volume and powered on the roughing pump. Once the main volume pressure fell below 0.5 Torr, we powered on the turbo pump as well. The main volume pressure reached 5e-6 Torr within ~30 minutes, consistent with previous experience, and was continuing to slowly fall.

Lastly, we initiated a 125 C bake-out of the entire system following our usual procedure. We plan to run this bake for 48 hours (i.e., through the end of the day Friday).

cleaning cleanroom and particle count

• 11:50 am: ran zero count test on particle counter
• 11:55 am: started particle count
  • zone 3:
    • 0.3 u: 1787
    • 0.5 u: 581
    • 1.0 u: 166
• zone 4:
  • 0.3 u: 623
  • 0.5 u: 290
  • 1.0 u: 124
• 12:17 pm: began surface check and wipedown, including softwalls
• 12:25 pm: started vacuuming the floor
• 12:36 pm: finished vacuuming the floor
• 12:44 pm: started mopping the floor
• 12:57 pm: finished mopping the floor
• 12:58 pm: started cleaning the buckets
• 12:59 pm: started mopping with IPA wipes
• 1:05 pm: finished mopping with IPA wipes
• 1:06 pm: changed sticky floor mats
• 1:08 pm: started particle count
  • zone 3:
    • 0.3 u: 1621
    • 0.5 u: 581
    • 1.0 u: 332
• zone 4:
  • 0.3 u: 1080
  • 0.5 u: 457
  • 1.0 u: 249

The replacement door for the HEPA garment cabinet arrived last week, and was installed on Thursday. However, it looks like there's a small gap between the door and where the hinge is attached to the cabinet frame. No screws were provided with the replacement door. If we want to perform any adjustments, we have to be very careful; the screws break very easily.

[Jon, Tyler, Aiden, Shane, Pooyan, Michael, Cynthia, Luke]

On Wednesday, we completed long list of work towards making the new lab (1129) fully operational and enabling the next phase of FROSTI testing. 

Cabinet Installation

Three new VWR cabinets with sliding glass doors were installed in 1129. Each unit measures 48" (W) x 22" (D) x 84" (H) and sits along the back wall (see attachment 1). The 350-lb. cabinets were laid in place by Facilities on Monday and permanentized on Wednesday. Work included:

• Earthquake anchoring to the masonry wall
• Sliding glass doors leveled
• Shelving installed
• Wiping down of interior and exterior surfaces with IPA wipes

Server Rack Installation

A new Tripp Lite 42U open-frame rack was laid in place in 1129 and anchored to the floor (see attachment 1). This rack will house all of our general-purpose and simulation computers, which will be relocated from the 1119 rack at a later time.

Lab Clean-Up

Following installation of the new cabinets and rack, we proceeded to organize and clean both labs. Work included:

• Moved parts and equipment into permanent storage in 1129 cabinets
• Wiped down surfaces in 1119 and 1129 with polypropylene IPA wipes
• HEPA-vacuumed floors of 1119 and 1129
• Mopped floor in 1119 with Liquinox solution
• Installed new sticky mats in 1119 and 1129
• Regular cleanroom cleaning and particle counts (see 302)
• Positioned new stainless steel gowning bench outside the cleanroom (see attachment 2)

At this point, the only piece of lab equipment still to be delivered is a HEPA garment cabinet for reusing our (semi-disposable) bunny suits. It is schedule to arrive in mid-February and will sit outside the cleanroom in 1119, in the former location of the HEPA flow bench.

On Thursday we installed the power conditioning/distribution equipment and networking equipment in the new 1129 rack. The hardware is identical to the setup in the 1119 rack and includes:

• Tripp Lite SU5KRT3UTF - 208V, 5kVA on-line UPS with 120V transformer
• CyberPower PDU20M2F12R - metered power distribution unit, (14) NEMA 5-20R
• Ubiquiti USW-Pro-48 - 48 port 10Gbps network switch

The UPS is connected to a 208V NEMA 6-30R outlet in the overhead cable tray, which is on the building's "standby" (backup power) circuit. An 8-ft L6-30 extension cord has been ordered to permanently run the power cable through the cable tray.

The network switch will be connected to a Cat6 cable that was recently run by ITS from the 1119 rack, allowing the lab's LAN to be extended into 1129. This Ethernet link remains to be tested.

I ended the bake of the UHV system (that began on Monday) at 6:23 pm today by switching OFF both PID controllers. The heaters elements were run at max power (24 V DC / 200 mA per element) during this bake, and I left them powered at the same level.

At the time, the instrument readings were as follows:

• Left high-limit controller: 138 C
• Right high-limit controller: 128 C
• Left PID controller: 100 C
• Right PID controller: 100 C
• Main volume pressure: 8.17e-7 Torr
• RGA volume pressure: 4.63e-7 Torr

I reproduced Cao's CE beamsplitter code (see below for example plots). I received the current info on the beamsplitter parameters for A+ and A# from GariLynn also. The next steps are to perform a similar power loss analysis on the anticipated A# beamsplitter.

Below is the proposed schematic for FROSTI optical testing, chosen so enough space is allotted for prototype assembly.

Steps to be taken include:

1. Reconstruct FLIR staging apparatus
2. Move test mass stand-in to cleanroom
3. Mark FLIR camera position on cleanroom optical table at correct distance
4. Run ethernet cable into cleanroom
5. Move FLIR aside to allow for more assembly space
6. Upon assembly completion, reposition FLIR onto optical table again

Tentative plan is to begin setup early next week.

cleaning cleanroom and particle count

• 5:10 pm: ran zero count test on particle counter
• 5:14 pm: started particle count

  NOTE: initial counts are significantly above allowed limit. ~10 times larger than ISO class 5 standard in the smallest size range. Realized partway through ceiling tile changes that the power/lights for some of the hepa fans in the ceiling frame had been turned off. May explain this high number. Have since turned fans back back on.

  • zone 3:
    • 0.3 u: 109208
    • 0.5 u: 16337
    • 1.0 u: 581
• zone 4:
  • 0.3 u: 51340
  • 0.5 u: 9228
  • 1.0 u: 581
• 5:33 pm: started replacing ceiling tiles
• 6:25 pm: began surface check and wipedown, including softwalls
• 6:33 pm: started vacuuming the floor
• 6:45 pm: finished vacuuming the floor
• 6:45 pm: started mopping the floor
• 6:50 pm: finished mopping the floor
• 6:52 pm: started cleaning the buckets
• 6:53 pm: started mopping with IPA wipes
• 6:58 pm: finished mopping with IPA wipes
• 6:59 pm: changed sticky floor mats
• 7:00 pm: started particle count
  • zone 3:
    • 0.3 u: 5404
    • 0.5 u: 1413
    • 1.0 u: 41
• zone 4:
  • 0.3 u: 1704
  • 0.5 u: 332
  • 1.0 u: 166

Summary

Today I finished implementing an RTS model to read out the integrated FROSTI RTDs (temperature sensors) via the CyMAC. The model is named "MSC" and is located at cymac:/opt/rtcds/usercode/models/c1msc.mdl. We successfully tested it with the heater elements operating in vacuum at low power (12 VDC), finding them to reach an average steady-state temperature of 160 C.

From the cymac host, the MEDM control screen can be accessed with the terminal command "sitemap" (from any directory).

Measurement Technique

Each FROSTI heater element [299] contains an internal two-wire RTD placed near the front emitting surface, which enables the temperature of the blackbody emitter to be directly monitored. From the measured temperature and the emissivity of the uncoated aluminum nitride surface (known to be ~1 in the IR), the radiated source-plane power can also be estimated.

The resistance of each RTD is measured via a ratiometric technique. The RTDs are powered in series with a 1 kΩ reference resistor located inside the readout chassis [305], whose temperature is not changing. The signal is obtained by taking the ratio of the voltage difference across each individual RTD to the voltage difference across the reference resisitor. The advantage of this technique is that the ratio of  the voltage differences is insensitive to changes in the current through the resistors (since they are all in series; see [271] for wiring diagram).

Implementation Detail

The signal flow is shown in Attachment 1. The eight RTD signals enter through ADC channels 0-7, along with the reference resistor signal on channel 8. The first set of filter modules apply a calibration gain to convert the signals from raw ADU counts to units of input-referred voltage. The ratio of each RTD signal to the reference resistor signal is then taken. The second set of filter modules multiply the voltage-difference ratios by the resistance of the reference resistor, 1 kΩ ± 0.01%, to obtain the RTD resistances in physical units of ohms.

Finally, a freeform math module is used to invert the quadratic relation between each RTD's resistance and temperature. The final signals passed to the third set of filter modules are the RTD temperatures in physical units of degrees C. The temperatures of the tungsten RTDs are estimated assuming TCR coefficients of A=0.0030 C^-1 (±10%) and B=1.003E-6 C^-2, which were provided by the manufacturer.

One DAC channel is used to provide the excitation voltage for the RTD measurement, which is visible on the far right of the control screen. At its maximum output voltage of +10 V, the DAC can drive a maximum current of 10 mA.

After updating the wiring in the RTD Chassis, a signal is now seen at each ADC input. However, there seems to be a discrepancy between the voltages I measured out with the multimeter (see below). Next steps include:

• Finish final debugging
• Calibrate ADC inputs with known voltage source (likely to use DAC).

Voltage Readings:

RTD 1: 0.576 V

RTD 2: 0.578 V

RTD 3: 0.598 V

RTD 4: 0.563 V

RTD 5: 0.477 V

RTD 6: 0.463 V

RTD 7: 0.456 V

RTD 8: 0.491 V

Reference Resistor: 5.463 V

Total Voltage: 9.665 V

After further modification of the RTD readout chassis (i.e. adding resistors, placing reference resistor in front of RTDs), here are the following direct measurements:

RTD 1: 0.484 V

RTD 2: 0.486 V

RTD 3: 0.503 V

RTD 4: 0.474 V

RTD 5: 0.495 V

RTD 6: 0.483 V

RTD 7: 0.476 V

RTD 8: 0.510 V

Reference: 5.847 V

Here are the Cymac signal readings:

RTD 1: 74

RTD 2: 67

RTD 3: 73

RTD 4: 45

RTD 5: 82

RTD 6: 75

RTD 7: 70

RTD 8: 71

Reference: 884

The one (possible) discrepancy here is the readout for RTD 4 via Cymac, since it's signal reading is ~30 counts lower than the others. I do not believe this is a wiring issue due to the direct measurements taken.

Took more data today and the chamber and elements are showing an even lower HC level than we have gotten before. It is safe to say that the elements are not contaminated and out gassing HC into the chamber.

Below is the data for the most recent bake. I believe the chamber is cleaner than it is actually showing as the RGA data was still getting lower while the data was being taken. I will take the data again tomorrow just in case. Still, the data shows that the chamber is basically as clean as it was before bake 10 and this means further power testing can proceed.

Helium leak tested the chamber again today to check if the sealant changed anything. The two primary target flanges from last time have improved significantly with the flange from the RGA on the cross now being below 2e-14. While the turbo pump flange was leaking at a rate of 4e-13. Much better than what it has been before.

Below are a basic diagram of what the RTD measurement circuit logically looks like and an example schematic of the actual wiring. The schematic wiring will be placed internally into a chassis, connected to the RTDs via DB25 cable.

The custom front and rear panels for the RTD readout chassis arrived last Friday. I installed them in the chassis frame to check their fit. They fit very well, so all that now remains is to complete the internal wiring and test the connections.

The chassis panel designs are archived to LIGO-D2300452 and LIGO-D2300453.

Below is the current state of the RTD readout chassis wiring. Initial continuity tests seem good, will run through one more time to confirm.

I performed another continuity test on the RTD chassis wiring, and everything seems to be set up correctly. The chassis should be ready for installation.

cleaning cleanroom and particle count

• 2:03 pm: changed sticky floor mats
• 2:05 pm: started particle count
  • zone 3:
    • 0.3 u: 4863
    • 0.5 u: 1205
    • 1.0 u: 872
• zone 4:
  • 0.3 u: 1953
  • 0.5 u: 789
  • 1.0 u: 457
• 2:35 pm: began surface check and wipedown, including softwalls and ceiling tiles
• 2:45 pm: started vacuuming the floor
• 2:56 pm: finished vacuuming the floor
• 2:57 pm: started mopping the floor
• 3:01 pm: finished mopping the floor
• 3:02 pm: started cleaning the buckets
• 3:05 pm: started mopping with IPA wipes
• 3:08 pm: finished mopping with IPA wipes
• 3:09 pm: started particle count
  • zone 3:
    • 0.3 u: 5528
    • 0.5 u: 2203
    • 1.0 u: 1662
• zone 4:
  • 0.3 u: 1080
  • 0.5 u: 415
  • 1.0 u: 332

Leak tested each flange and weld and only found two flanges to have noticeable leaks with the electron multiplier on. These were the turbo pump flange and the RGA flange that connects to the cross. The RGA one is rather new as it has not had a measurable leak before and it was around 2 e-8. We then applied the new sealant to these two flanges as directed by the instructions on the packaging.

Then after waiting a few minutes for the sealant to dry we started the bake. We got the PID controllers set to 120 after many steps and we checked the temperature of the flanges throughout this increase. The flanges never reached 70C with the electronics still left on it. The RGA was left on as well.

Installed the heater elements into their fixture and prepped the cables by twisting the wires into pairs. We also installed the pins onto the wires and placed them into the peek DB 25 connector. The installation tool we had did not fit the pin size we had so the pins needed to be installed by hand by opening the connector and holding them in place. In the future we will need to make sure we twist the wires together, group them, and then splice them all to the same size for easier installation. We then grouped all the twisted pairs into a bundle and zipped them together. On the left with two peek zip ties is the power and on the right is the RTD with one peek zip tie. This orientation remains true when looking at the feed through flange from the outside with the power port on closest to the wall.

We also installed the heater elements numbered 1-8 starting from the left in image 3. These elements have numbers as resistance data was taken before as to identify the heaters after they are in the chamber. After installing the DB 25 connectors we tested that the pins were in the right orientation by using a volt meter and testing the resistance where the cable runs into the the actual power supply. It seems that all the pins were properly installed and the resistance values all match with each one gaining about 2 Ohms from the cable itself.

Then the pump down was started. The pump was very slow and we suspected a leak but after changing the o-ring pump down was not any faster and we decided to leave it over break as it seemed to just be water outgassing from the aluminum. The chamber is now able to be RGA scanned and leak tested before the next bake as it is low enough pressure.

[Jon, Tyler, Aiden, Luke]

On Friday we completed assembly of the new stainless steel-topped benches in 1129. We then moved the clean and bake equipment from 1119 to its new larger space in 1129. This included the HEPA flow bench, ultrasonic washer, deionized water drum, nitrogen tanks, and forced-convection oven. The oven was re-anchored to the wall with earthquake restraints in its new location.

The power cords still need to be permanently routed, but the new clean and bake lab is otherwise ready for use.

Update: I have completed permanent routing of the electrical cables. I also ran the ultrasonic washer's drain line to the sink drain (the current hose does reach). The new clean and bake lab is now fully operational.

I measured the temperature of the flanges where some of the electronics will go and I found that the RGA flange was at 55C and the two full range gauges were at 65C. I also stopped bake 9 to cool down for measurement.

1. Turn off the RGA filament and disconnect it.

2. Record the pressure and then close the angle valve and gate valve on the RGA line to isolate it from the system.

3. Turn off the backing and turbo pump and let the turbo pump spin to a stop by slowly leaking the chamber. The slower the safer.

4.Slowly open the vents on the chamber and the turbo pump. Making sure not to raise the pressure too fast.

5. Once done venting the chamber, open the lid by removing the bolts and prying the lid open with a long flat head screw driver.

6. Removed previous parts and placed them into clean bags. Place new parts inside of the chamber and group them together close to the center.

7. Place the lid back onto the chamber and tighten the bolts in a circular pattern until tightened all the way with the wrench.

8. Make sure all vents are closed and turn the backing pump back on.

9. The turbo pump can be turned back on when the pressure reaches e-1 torr.

10. Wait until the chamber reaches a pressure of e-6 torr before opening the angle and gate valve on the RGA line. After the RGA line is open and the pressure is still below e-6 torr, the RGA filament can be turned on and a leak test of the lid should be performed.

11. After the leak test shows no leaks, proceed with starting the low temp bake.

Below is the procedure we will follow to assemble the FROSTI prototype.

1. Install SS guide rods and bottom Macor spacers in bottom reflector
2. Install AlN elements on top of bottom Macor spacers
3. Install upper Macor spacers on top of AlN elements
4. Feed unterminated power and RTD leads through slots in upper reflector
5. Install upper reflector, using guide rods to slowly lower into position
6. Install vented SS bolts for reflectors; Macor bolts for heater elements
7. Remove SS guide rods
8. Bundle power and sensing cable with PEEK cable ties and SS cable mounts
9. Terminate power and sensing cable bundles with PEEK DB25M connectors

The workbenches are now completely assembled and put into their final places. Additionally, the tool chest has been moved.

[Jon, Tyler, Shane, Luis]

On Wednesday we completed the migration of the electronics workshop from 1119 to the large new workbenches in 1129. The two workstations pictured closest to the front of the room are for electronics assembly and testing, while the two in the rear will house LIGO CDS workstations. We moved all of the tools, cabling, and soldering and test equipment from 1119 to this new location. We also moved the large tool chest to 1129, as pictured, and moved the smaller tool chest to 1119 in its place.

The electronics workbench is ready for use. 

cleaning cleanroom and particle count

• 12:30 pm: ran zero count test on particle counter
• 12:32 pm: started particle count.
  • zone 3:
    • 0.3 u: 59,488
    • 0.5 u: 9561
    • 1.0 u: 706
• zone 4:
  • 0.3 u: 7732
  • 0.5 u: 1912
  • 1.0 u: 290

NOTE: Frame ceiling tile collapsed in cleanroom, explaining insanely high 0.3 u particle count in zone 3 (nearly 6 times above limit). Wiped down tile and put it back in ceiling frame.

• 12:56 pm: began surface check and wipedown, including softwalls
• 1:16 pm: started vacuuming the floor
• 1:32 pm: finished vacuuming the floor
• 1:33 pm: started mopping the floor
• 1:47 pm: finished mopping the floor
• 1:48 pm: started cleaning the buckets
• 1:53 pm: started mopping with IPA wipes
• 2:05 pm: finished mopping with IPA wipes
• 2:06 pm: changed sticky floor mats
• 1:53 pm: started particle count
  • zone 3:
    • 0.3 u: 6401
    • 0.5 u: 3450
    • 1.0 u: 1787
• zone 4:
  • 0.3 u: 4073
  • 0.5 u: 2452
  • 1.0 u: 1039

Took some RGA data of the chamber after it has been cooling down. I do not believe that this data accurately shows the HC levels in the chamber as the pressure is still above where it was at before the bake and was still falling. I believe more time is needed to let the pressure fall and for the RGA filament to remain on to return to a point where the data can be trusted.

Turned off the heating tape today in anticipation to take more RGA data on Sunday or Monday morning before the meeting.

Came into the lab in the morning to check on the chamber heating. I decided to set the PID controllers to 110C rather than 120C as the chamber lid and wall were reading near 140C. With the PID controllers at 110C the chamber lid and wall now read 126C and 132C. Currently the PID controllers are placed on the cross in front of the RGA and the reducing nipple in front of the turbo pump. I believe this is a good equilibrium and will leave the tape on until Saturday when it will be turned off to cool down.

After the bake is done on Saturday it will be cooled down and RGA data will be taken to measure the out gassing rate of the stainless steel fasteners inside the chamber. Then on Tuesday we will plan to vent and open the chamber again to put the macor inside and repeat the another low temp bake and then test the macor early in week 11. Then the next material will be the aluminum mounting hardware for mounting the heaters and that should hopefully be done before the end of week 11 so the heaters can be tested afterwards after being cleaned with vector alpha wipes.

The tabletops have been attached to the workbench frames. Unfortunately, one of the tabletops came out of the box with a large scratch and small dent in the middle. One of the electric top shelves is ready to be attached to the undamaged table, but the other is yet to be opened. Assembly will be completed Wednesday morning.

Update: I was able to put the FROSTI power controller on the lab network. It is connected to the switch in the top of the rack and is assigned a static IP address of 192.168.1.12 and an NDS hostname of relay1.

The controller can be remotely accessed through an SSH command line interface as well as an HTML webpage, which can be opened from any web browser on the lab network by navigating to the above IP address (the login credentials are the same as for the workstation computers).

There is also an unofficial Python package for interfacing with the controller: dlipower. We will investigate using this package to interface the controller with soft EPICS channels hosted on the CyMAC. This will allow us to create a custom MEDM screen for controlling the FROSTI heater elements.

Edit: The login credentials were set up to be the same as for the CDS workstations.

Luis and Aiden vented the chamber today. We closed off the RGA section and then proceeded to open the the vent on the main body after turning off the turbo and backing pump. We then opened the lid and placed in all the stainless steel hardware that will be used in evaluating the FROSTI optics and heater elements. We also inspected the weldments before closing it up. Check the clean and bake data base where there is now a new section outlining the parts in each test. We then closed the lid, tightened the bolts, turned the backing pump back on and let the pressure drop until it was below 1e-1 torr. Then turned the turbo pump back on and after a few hours the pressure was back down to 4.16e-7 torr. The RGA was turned off during all of this and was turned back on when done even though we closed both valves to keep the RGA volume under vacuum.

[Tyler, Shane, Mohak, Cynthia, Luke, Michael, Luis]

[Aiden, Luis]

Tested every weld and flange to find leaks. Only found that the flange on the turbo pump and reducing nipple was still at 2e-9 torr on the leak. The chamber still rose in pressure when the two gate valves were closed but no noticeable leak could be found on the lid or welds.

cleaning cleanroom and particle count

• 3:37 pm: started particle count
  • zone 3:
    • 0.3 u: 1205
    • 0.5 u: 748
    • 1.0 u: 249
• zone 4:
  • 0.3 u: 1496
  • 0.5 u: 748
  • 1.0 u: 290
• 3:57 pm: began surface check and wipedown, including softwalls. NOTE: vacuum chamber insulation crumbling at edges, dropping loose flakes. Scatters residue whenever jostled, so wiping it down just releases more. Not enough flakes are being released for it to be a major issue, but definitely something to keep an eye on.
• 4:18 pm: started vacuuming the floor
• 4:29 pm: finished vacuuming the floor
• 4:30 pm: started mopping the floor
• 4:35 pm: finished mopping the floor
• 4:36 pm: started cleaning the buckets
• 4:41 pm: started mopping with IPA wipes
• 4:52 pm: finished mopping with IPA wipes
• 4:52 pm: changed sticky floor mats
• 4:53 pm: started particle count
  • zone 3:
    • 0.3 u: 3367
    • 0.5 u: 1787
    • 1.0 u: 914
• zone 4:
  • 0.3 u: 1039
  • 0.5 u: 498
  • 1.0 u: 249

1. Run a second RGA degas cycle, but next time with the main volume valved off with only the RGA volume being pumped (through the bypass line). This will prevent "boiled off" particulate from entering the main chamber and will also increase the pumping rate for the RGA volume, reducing the amount of particulate that resettles on the RGA filament.
   
   
2. I also noticed that the SRS manual states that the filament is designed to be long-lived and it is recommended to leave it on any time the RGA is on. By leaving the filament on all the time (i.e., hot), we could reduce the amount of particulate that is evidently settling on it between scans. I am checking whether LIGO Lab does this in their own chambers.

As a follow up ELOG 261, I have received advice from one of the vacuum experts at LIGO Hanford on best practices for our RGA:

1. For future RGA degassing, definitely keep the main volume isolated, since it could contaminate the main volume with everything that just got cooked off of the filament. So the procedure should be to (i) close both gate valves, (ii) ensure the angle valve on the bypass line is open, (iii) initiate the degas cycle on the RGA, (iv) pump the RGA volume through the bypass line, until its pressure returns to its pre-degas level.

2. Repeated degassing of the filament will definitely wear it down much faster, so do this operation sparingly.

3. As long as the pressure of the RGA volume is in the UHV range (~1e-9 torr), best practice is to leave the filament on. This keeps it hot which helps prevent particulate from settling on it. However the electron multiplier should stay off when not actively taking scans, as it will wear down if left on all the time.

[Jon, Shane, Luis]

My repair of the internal ribbon connecting the ADC to the adapter board resolved the timing signal problem. After this repair, we were able to start the front-end IOP model and checked out the RTS diagnostic screens (pictured below). All indicator lights were green except for the DK flag (indicating the DAC outputs are not enabled) and the DAQ flag (indicating that the system is recording data to disk). Those were both as expected, because the DAQD data acquisition service was not set up yet and the DAC outputs are not enabled until at least one user model (which outputs signals to the DAC) is started. I created and installed a simple user model (C1MSC) and confirmed that the DK flag clears once this model starts.

I later attempted to set up the DAQD service, which is needed to save data, but am yet to successfully debug it. I have received some guidance from one of LIGO's CDS experts and will try it at my next opportunity for lab work.

After initial analysis from last week on a single RTD, I then extended to looking at all 8 in series with R_ref (set to 1 kOhm). Shown below are the edge cases for the setup:

• RTDs are all at ambient lab temperature. This would correspond to a minimum resistance value.
• RTDs all read out 400 C. This gives the maximum resistance value.

The results show that indeed only a few mA of current is drawn even at room temperature (a little above 5.5 mA), and this will continue to decrease with increasing temperature. The voltage across a single terminal, at a maximum, is only about 5.4 V.

cleaning cleanroom and particle count

• 12:30 pm: Tyler and Aiden started organizing cables in cleanroom
• 12:35 pm: started particle count in flow bench
• 0.3 u: 11681
• 0.5 u: 3284
• 1.0 u: 1039
• 12:50 pm: started cleanroom particle count
  • zone 3:
    • 0.3 u: 14549
    • 0.5 u: 10351
    • 1.0 u: 6194
• zone 4:
  • 0.3 u: 10808
  • 0.5 u: 4655
  • 1.0 u: 1953
• 1:07 pm: began surface check and wipedown, including softwalls
• 1:19 pm: started vacuuming the floor
• 1:28 pm: finished vacuuming the floor
• 1:29 pm: started mopping the floor
• 1:33 pm: finished mopping the floor
• 1:34 pm: started cleaning the buckets
• 1:37 pm: started mopping with IPA wipes
• 1:39 pm: finished mopping with IPA wipes
• 1:40 pm: changed sticky floor mats
• 1:41 pm: started particle count
  • zone 3:
    • 0.3 u: 8397
    • 0.5 u: 5071
    • 1.0 u: 2618
• zone 4:
  • 0.3 u: 6651
  • 0.5 u: 4323
  • 1.0 u: 2120

[Jon, Tyler, Shane, Peter, Luis]

Today we completed the first phase of lab clean-up. Activities included:

• CF/KF parts stored under the cleanroom table were removed and transferred to Physics 1129
• Cleanroom workbench cleared, with all FROSTI hardware collected into one of the large SS bins
• High surfaces outside the cleanroom (lights, table enclosure frames, rack, cabinets) wiped down with IPA wipes
• Floor HEPA-vacuumed outside the cleanroom
• Sticky mats changed throughout the lab

Tomorrow, we will complete turn-over of the cleanroom (HEPA vacuuming of floors, mopping of floors, IPA wiping of softwalls and work surfaces). Shane will post a forthcoming measurement of the cleanroom particulate levels, post-turnover.

Preliminary RTD calculations are shown below, given an input of 10 V and desiring a few mA of current. It looks like R_ref should be at least 1 kOhm (refer to plots/circuit below), keeping in mind we need to have <10 V input for the ADC.

RP: The Red Pitaya Software was updated to OS 2.00. All examples on the RP website should run without issue.

• Topmost Sorensen: +24V (reserved for FROSTI)
  • Positive terminal:
  • unconnected for now
  • Negative terminal: [negative terminal is grounded]
  • jumper to Sorensen ground screw
• Sorensen 2nd from the top: +18V
  • Positive terminal:
  • white power cable wire for AA chassis
  • white power cable wire for AI chassis
  • white power cable wire for BI chassis
  • white power cable wire for BO chassis
  • Negative terminal: [negative terminal is grounded]
  • jumper to Sorensen ground screw
  • black power cable wire for AA chassis
  • black power cable wire for AI chassis
  • black power cable wire for BI chassis
  • black power cable wire for BO chassis
• Sorensen 3rd from the top: -18V
  • Positive terminal:[positive terminal is grounded]
  • jumper to Sorensen ground screw
  • green power cable wire for BI chassis
  • green power cable wire for BO chassis
  • Negative terminal:
  • green power cable wire for AA chassis
  • green power cable wire for AI chassis
• Bottommost Sorensen: +6V
  • Positive terminal:
  • white power cabe wire for timing chassis
  • Negative terminal: [negative terminal is grounded]
  • jumper to Sorensen ground screw
  • green power cable wire for timing chassis
  • black power cable wire for timing chassis

FLIR: After some adjustments, the plot generated from the FLIR measurements look much more symmetric (see attachment). There are more included grid points, which smooths out the curve as compared to last week.

Red Pitaya: It looks like a new OS update was released for the RP, which includes a new Python API (was previously only available in C). I'm going to try and update the one we have currently running in lab.

By 5:30 pm Friday, the pressure had reached 8.6e-8 torr and was continuing to fall. So it seems we are OK to proceed with permanentizing this configuration (cable routing, heater tape reinstallation).

cleaning cleanroom and particle count

• 3:16 pm: started particle count.

  NOTE: we are not within the ISO class 5 standard for any size ranges in zone 3. ~6000 above limit in 0.3 u, ~2000 above in 0.5, ~200 above in 1.0

  • zone 3:
    • 0.3 u: 16,711
    • 0.5 u: 5612
    • 1.0 u: 1039
• zone 4:
  • 0.3 u: 6817
  • 0.5 u: 2369
  • 1.0 u: 249
• 3:35 pm: began surface check and wipedown, including softwalls
• 3:50 pm: started vacuuming the floor
• 4:00 pm: finished vacuuming the floor
• 4:01 pm: started mopping the floor
• 4:06 pm: finished mopping the floor
• 4:07 pm: started cleaning the buckets
• 4:08 pm: started mopping with IPA wipes
• 4:14 pm: finished mopping with IPA wipes
• 4:15 pm: changed sticky floor mats
• 4:18 pm: started particle count
  • zone 3:
    • 0.3 u: 23,113
    • 0.5 u: 9686
    • 1.0 u: 1371
• zone 4:
  • 0.3 u: 7191
  • 0.5 u: 2951
  • 1.0 u: 290

Took some RGA data when we came into the room. The pressure of the chamber was 8.63e-8 Torr before turning on the RGA filament. We saw the usual spike in pressure when the filament was initially turned on. Took some data and saw that the chamber was definitely dirtier since the vacuum upgrade. See figures below.

Put the heater tape back onto the section that was removed. We may need to rearrange the heater tape again as there was not much heater tape to go around the upgraded section. We also tried to get some of the extra insulation around this section and we able to get some on around the 6-8 inch reducer.

We then took off the electronics for the gauges and the RGA, added the new extension cords to the PID controllers, and then started bake 6 which will go to 120 degC and stay that way until most likely Monday. The pressure before starting the bake was 8.28e-8 Torr.

Continued tightening bolts on the turbo pump and 6"-8" reducer to reduce the leak. The final leak test values for the turbo pump flange was 3.0 e-9 and the other 6"-8" reducer flange was 4.0 e-9.

We will continue to let it pump down as the screws could not be tightened anymore. Looks like new gaskets will be needed to reduce the leaking on these flanges.

[Jon, Tyler, Aiden, Peter]

Upgrade of the UHV system to a larger turbo pump began today. After obtaining a final RGA scan in the old configuration (Aiden to post), we vented all three volumes and proceeded to disassemble the 4.5"-diameter pump line. We completed installation of the new 6"-diameter pump line to the point where the new turbo pump will attach. This includes a 6" manual gate valve, 6"/2.75" reducing cross, and 6"/8" conical reducing nipple, as pictured below. Strain relief was also installed due to the longer length and greater weight of the new fittings.

Tomorrow we will continue with attaching the Varian TV 551 pump and perform a pump-down test. If this pump is confirmed to be operable, then we will relocate the entire system ~18" closer to the middle of the table and permanentize the setup.

Today's CyMAC work:
• Finished assembling external power supply cable for the timing chassis (see attached image)
• Also did some debugging of AA and AI chassis re: power issues. After testing voltages at various test points on the power regulator board (TP1-TP6) in the AA chassis, it seems like it's the source of the problem. Used bench DC power supply to test, running 15V, and the correct voltage is coming in to the board but something significantly smaller is being output. We're also getting unexpected negative signs on voltage at certain test points, with leads in correct positions
• Upon further examination, it looks like the lights on the filter boards are actually turning on (in both the AA and AI chassis), though it's only 2/4 lights on each board and they are very faint
• Corrected DC on/off switch spade lug orientation in AI chassis.
• Tested AI chassis power regulator board to see if the problem was the same, and found again that voltage coming in was correct, and voltage going out was not.
• In case of interest in exact numbers, results were as follows:
  • Voltage difference between TP1(+Vin) and TP6(-Vin) is ~30V
  • Voltage difference between grounded chassis wall and TP1 (+Vin) is ~15V
  • Voltage difference between grounded chassis wall and TP6(-Vin) is ~-15 V
  • voltage difference between TP2(+Vout) and TP5(-Vout) is ~3V
  • Voltage difference between TP3 (gnd) and TP2(+Vout) is -0.065V
  • Voltage difference between TP5(-Vout) and ground is ~3V

cleaning cleanroom and particle count

• 10:06 am: ran zero count test on particle counter
• 10:07 am: started particle count
  • zone 3:
    • 0.3 u: 2203
    • 0.5 u: 831
    • 1.0 u: 540
• zone 4:
  • 0.3 u: 374
  • 0.5 u: 124
  • 1.0 u: 124
• 10:25 am: began surface check and wipedown
• 10:34 am: started vacuuming the floor
• 10:44 am: finished vacuuming the floor
• 10:45 am: started mopping the floor
• 10:49 am: finished mopping the floor
• 10:50 am: started cleaning the buckets
• 10:57 am: started mopping with IPA wipes
• 11:01 am: finished mopping with IPA wipes
• 11:02 am: changed sticky floor mats
• 11:03 am: started particle count
  • zone 3:
    • 0.3 u: 2535
    • 0.5 u: 374
    • 1.0 u: 166
• zone 4:
  • 0.3 u: 581
  • 0.5 u: 41
  • 1.0 u: 0

Came in to take RGA data and found the turbo pump drawing .38 Amps. This was much higher than what it was on Friday. I investigated and found that the breaker had flipped controlling the power strip that the scroll pump was on. The scroll pump was thus not running. I flipped the breaker back and turned the scroll pump back on. I do not know if this will be a reoccurring problem as this has happened before, or if this was due to the storm. Either way the scroll pump is running and the turbo pump is now only drawing .18 Amps at 31 C.

Below are the graphs for the RGA scan that I took before starting bake 4. I have not overlaid them yet so the first one is for Argon leak closed and the second is the Argon leak open. It seems that the chamber had gotten dirtier since the leak and there is still a lot of water left in the chamber. I assume the water will go away after the low temp bake but the HC count may not go down without a longer baker. I also measured the pressure before starting the bake and it was 4.16 e-7 and 3.31 e-7 torr for t he main body volume and RGA volume respectively.

When starting the bake I noticed that the temperature sensor placed on the cross in the RGA volume was reading 40 C hotter that what the PID controller was reading for the lid. I had to remove some of the heater tape from the cross as it was way too hot compared to the lid. After removing the second strip across the cross it is still much hotter than most parts due to it being such a small part compared to the large lid. I hope that after a little bit of equilibration time that the difference between these numbers will go down. Both PID controllers were set to 120 C. The RGA cross was reading 130 C and the Turbo pump cross was reading 76 C.

Put the heating tape back on and made sure to have 4 coils around the barrel of the chamber. To make this happen I did not put any heater tape on the ports but made sure to place some of the heater no more than 1 inch away from the ports. Also re-placed some of the heating sensors. For the PID controllers there is one sensor placed on the lid and one sensor placed on the barrel. For the temperature alarms one sensor was placed near the flange of the turbo pump and another placed on the cross in the RGA line. Note that all four of these sensors were placed under the heating tape compared to the last few bakes where they were on top.

The insulation was also put back on and now the chamber should be ready for a low temperature bake after some RGA data is taken before for comparison.

Pulled off the rest of the heater tape along with the aluminum tape left behind. The aluminum tape adhesive left behind a ton of junk on the walls of the chamber. This is probably due to excessive heating. In order to get the adhesive off I sprayed a vector alpha wipe with acetone and wiped down the walls. This took a lot of acetone to get it off.

When removing some of the aluminum tape I noticed small sections that seemed to have been melted to the silicone part of the heater tape and would have been damaging to try and forcefully remove it.

The heater tape is now ready to be put on again but now with the start of the tape placed on the other side so that the PID controllers can be placed on the shelf above the chamber and be seen outside of the curtain.

[Dr. Richardson, Aiden] Large Update

Removed most of the insulation on the chamber in order to pull back some of the heater tape to get to the flange connecting the bypass line to the valve under the RGA line. Most of the heater tape on the bottom half of the chamber was pulled off and the rest will need to be removed as well in order to place the start of the heater tape on the barrel of the chamber rather than one of the flanges.

Engaged the valve under the RGA line to prevent it from getting more contaminated. Turned off the turbo pump. Turned off the scroll pump. Let the turbo pump sit for a few minutes to let the fans stop. Then leaked the turbo pump volume by turning the knob slowly on top of the turbo. Then proceeded to unscrew the bypass line after done leaking the volume. Replaced the copper gasket and then proceeded to screw it on while maintaining a circular path to ensure equal pressure on the gasket. BEWARE THAT REUSING SILVER PLATED SCREWS HAS A HIGH CHANCE OF STRIPPING THE SCREW AND WILL RESULT IN A LOT OF WORK TO GET THEM OFF. IT IS RECOMMENDED TO USE NEW SILVER SCREWS. HOWEVER WE HAVE NONE LEFT SO DO NOT TRY TO REUSE ANY SCREWS UNTIL WE HAVE SPARES. We were able to use the remaining two spare screws to tighten the flange to a point where it will not tighten anymore.

Then the lid was removed in order to inspect the inside of the chamber and the Viton O-Ring. The chamber had no physical damage and the viton had some visual damage that may correlate to the failure observed during bake 3. Note that some metal chips were found inside of the o-ring groove and needed to be removed. We changed out the o-ring for a new one and placed the old one inside of an anti static bag labeled "Viton O-Ring". Put the lid back on after inspecting for damage and put the bolts on hand tightened. Started to pump down again by turning on the scroll pump first until full range gauge 1 read below 1 torr and then began to turbo pump. The turbo pump was running for 1.5 hours until it plateaued around 3e-4 torr. We then realized the bolts on the lid needed to be tightened more with a wrench. After further tightening the pressure quickly dropped to 6e-6 torr. In the future the bolts should be tightened with a wrench from the begining.

Then proceeded to Helium leak test every weld, flange, and valve. Two of the flanges needed a little more tightening such as the 2 6" flanges. Other than that the only noticeable leak was from the flange just fixed today, however the leak is 10 times less than how it was yesterday and will most likely not hold the chamber back from reaching low 10e-8 torr pressures.

[Dr. Richardson, Aiden]

DO NOT TOUCH ANY VALVES ON THE CHAMBER. THERE IS A PRESSURE DIFFERENTIAL BETWEEN THE RGA LINE, TURBO PUMP LINE AND THE MAIN VOLUME. THE TURBO PUMP WILL BE DESTROYED IF OPENED.

Closed the valves to the turbo pump line and RGA line. Turned the turbo pump back on and saw that the pressure in the RGA Line and Turbo pump line was going down so there was no large leak within that line or with the valves as the main body pressure stayed constant. Then raised the pressure of the main body of the chamber as we suspect the viton o-ring has failed and needs to be changed. The bolts to the lid of the chamber were also removed but the lid was left on.

Then performed a helium leak test on the section of the system that was under vacuum. We found two flanges that had small but significant leaks compared to the others in the lines. The flange connecting the full range gauge to the cross and the flange connecting the stainless steel tube to the valve under the cross. These showed large spikes when sprayed with helium and were then tightened to hopefully fix it. After tightening, the flange under the full range gauge was fixed as the bolts were pretty loose and tightening reduced any spike seen on leak test. The other flange on the SS tube could not be fixed with tightening and it still shows signs of helium leaking through. This flange will need to have its gasket changed to fix this leak. Then left the system where it is in the picture for further changes tomorrow August 11. Again, DO NOT TOUCH THE VALVES ON THE RGA LINE AND TURBO PUMP LINE AS THERE IS A PRESSURE DIFFERENTIAL AND IT WILL DESTROY THE TURBO PUMP IF OPENED.

Note: We also found that the pump under the table had flipped the breaker and needed to be turned back on. This may be something to look into.

I delivered new NEMA 5-15 (120V / 15 A) power cables to the lab for the following items:

• WS2 (cleanroom) cart - 10ft cable
• Electronics workbench overhead LED - 10ft cable
• Both PI heater controller sets - (2) 6ft cables

I installed the new cables on the WS2 cart and the workbench myself, and left the two 6ft cables (as pictured below) for Aiden to install on the PID controllers after the current bake is finished.

Vacuum Chamber equilibrium temperature for bake 3 are 126 C and 88 C for the chamber wall and turbo pump flange respectively. There were reached with the PID controllers both being set to 150 C.

Also noticed some discoloration around the port insulation. It could be burned from being exposed to the heater tape directly without insulation or it could be that the insulation, which looks much different, is depositing something around the ports.

The turbo pump overheated and the heating tape had to be turned off in order to get the pump back online. It was unusually hot at 52 C. Hottest it got in bake 2 was 38 C.

Did some further testing to determine if it was within reason to increase the temperature of the chamber. I used a thermometer and pulled back some insulation to test many points on the chamber. Mainly focused on the barrel and the bottom lid of the chamber to see if it was possible to increase the temperature of just the PID controller that is powering the bottom half of the chamber.

Found that the barrel of the chamber seems to be hotter than what the sensor is saying, 125 C. Found many points on the barrel that reached 140 C. I believe this is because the sensor is taped on top of the heater tape rather than in between the aluminum and the heater tape.

Also measured many points on the bottom lid as it has the same configuration the top did before it damaged the insulation. It seemed to be consistently at 150 C but I was able to find a couple points that were hotter around 160 C. These hotter spots were most likely the heater folds. There is not much we can do about this as removing the insulation for fixing would required a very invasive procedure to do it safely.

Then moved to the stainless steel tube that connects the RGA and Turbo pump lines. This tube was around 150 C but many points on it were hotter around 160 C. Before another bake I think some of the tape around the tube may need to be pulled back and relocated to avoid damaging insulation while also providing more heat to the main body of the chamber.

Measured a couple more points on the cross that connects the RGA and the full range gauge and found it to be around 130-140 C which means this section could be hotter as the electronics of the full range gauge can reach 150 C.

Over all I believe that the chamber temperature should not be increased in its current state as the bottom lid is a concern with what happened with the top in the second bake. Some optimizations could be made for a fourth bake however. Moving the temperature sensors to be between the heater tape and chamber. Pulling some of the heater tape from the stainless steel tube and relocating it to the main body of the chamber. Moving the PID temperature sensor on the tube to be on the bottom lid or another hotter spot. These are some changes I would make for a fourth bake but maybe this bake could be the last with how the second bake went.

Moved the temperature sensor on the PID controller to one of the switch backs on the lid.

Also started the next bake with both PID controllers set to 150 degC. When leaving the temperature sensors above the chamber read 119 C and 83 C. These sensors are on the chamber wall and flange in front of the turbo pump respectively.

Changed the pre filter inside of the 3 stage HEPA system next to the soldering station. It was rather dirty and I have attached images with a clean filter on the left and the used one on the right. I reset the pre filter age on the system. I tried to see if I could tell if the HEPA filter was dirty but I could not see it. I did not reset the age of the HEPA or UV stations. They are currently 378 days old.

Dr. Richardson and I took off the insulation on the lid again to add more insulation in-between the heater tape folds in addition to what was added on top of the tape after discovering discoloration. Also cleaned the lid with IPA wipes.

Also took more RGA data, one with the leak closed and one with the leak open. The graphs below this show that the SNR is improving with the ratio now looking to be around 3. The chamber is still too dirty to be commissioned and we will need to be baked again soon.

Plugged the temperature sensor back in after getting another extension cord. Removed the electronics box for the RGA as well as the full range gauge above the RGA line.

1. I was able to plot the final result with the data to the heater. I attached below the "3Combined_HighTemp_Gaussian_Plot." in this plot we can see better behavior on the Gaussian compared to the plot in ELOG 169, I was using the same data but with a different approach. On the ELOG 169, we have the center point isolated data and this new plot is the temperature more than 70 C isolated because we have a very good heater temperature distinguish do background. For the all data I got I was using a power current of 0.20A. To get the data I waited for 30 minutes until the heater became stable and after that, I started to take snaps, I took more than one snap for each one different 6 positions on the screen, and We can see the positions on ELOG 167.
2. Also I attached the calibration plot ("calibration_plot") between the measurements with the FLIR camera and thermocouple and we can see looks good if we compare the final plot.
3. For better analyses I attached a plot of the calibration line on the Gaussian plot.
4. To do: I will finish the final report.

Took some more data to look at the HC count. Initial data was from leaving the Argon leak closed and then left it open for 15 minutes and then took data for the open scenario. Attached are the graphs for these where attachment 1 is the closed scenario and attachment 2 is the open scenario.

From these graphs it looks like the signal-noise ratio of our calibration line is poor with the ratio between these two being 1.3. This means that the calibrated leak is barely being detected over the background. This should improve with more baking and pumping. I have also now attached overlayed graphs comparing the chamber when the leak is closed versus when it is open. As well as one comparing the chamber right after the bake versus the most recent data both with the leak open.

cleaning cleanroom and particle count

• 11:08 am: started particle count
  • zone 3:
    • 0.3 u: 4198
    • 0.5 u: 1080
    • 1.0 u: 581
• zone 4:
  • 0.3 u: 1247
  • 0.5 u: 623
  • 1.0 u: 415
• 11:24 am: break for removal of vac chamber insulation (pictures attached), with counts before removal as seen above, and counts after removal/replacement for zone 3 as follows:
  • zone 3:
    • 0.3 u: 2993
    • 0.5 u: 415
    • 1.0 u: 207
• 12:02 pm: began surface check and wipedown
• 12:13 pm: started vacuuming the floor
• 12:25 pm: finished vacuuming the floor
• 12:26 pm: started mopping the floor
• 12:32 pm: finished mopping the floor
• 12:32 pm: started cleaning the buckets
• 12:37 pm: started mopping with IPA wipes
• 12:43 pm: finished mopping with IPA wipes
• 12:45 pm: changed sticky floor mats
• 12:47 pm: started particle count
  • zone 3:
    • 0.3 u: 2951
    • 0.5 u: 290
    • 1.0 u: 41
• zone 4:
  • 0.3 u: 290
  • 0.5 u: 0
  • 1.0 u: 0

• Today I got more data to plot the Gaussian. So I took more snaps in each position for the six different spots than we be using to have a better calibration of the FLIR collected data. I attached the new plot below. Also, I did the same plot for each region as on the Elog 167 but I have more than 20 pics because I was using a big number of data so I just attached one example below.

To access the Elog, click here.

• Also I think we have some real (non-ideal) heat diffusion by the screen and not noise like Dr. Richardson suggested. I was testing today and we can see the first pic before the start heater source turns on, the second pic is at 120.2 C (0.31A) with the heater on and the last pic is after the heater source cooled back down to room temperature. Just in the second pic, we have a strong spot on the top, so it looks like a non-ideal diffusion.

Took another set of RGA data after the second bake has cooled down to 27 degC.

Just by visual comparison to the other graphs, the HC levels of the chamber has gone down further. I will soon overlay the data for an easier comparison.

I also reinstalled the full range gauge above the RGA line. It is still adjusting itself downwards so I will have to check again to get an accurate measurement of the pressure.

• Today I was able to plot a graph for the isolation point on the center of the heater. I got data from six different positions on the screen (I shifted the all coordinates). I extracted the data for the center point and plot the Gaussian with this extracted data for temperature. I attached the all plots below
• Also I took a snap using the black wall and with the heater at 120.1 C (0.30 A) try to have less noise but we can see this is not very good. At this temperature, we have noise on the top and I don't understand why because the heater is not in this location. I attached a snap below.

cleaning cleanroom and particle count

• 1:10 pm: started particle count
  • Zone 3:
    0.3 u: 2535
    0.5 u: 207
    1.0 u: 41
• Zone 4:
  0.3 u: 789
  0.5 u: 41
  1.0 u: 0
• 1:30 pm: began surface check and wipedown
• 1:41 pm: started vacuuming the floor
• 1:55 pm: finished vacuuming the floor
• 1:57 pm: started mopping the floor
• 2:01 pm: finished mopping the floor
• 2:02 pm: started cleaning the buckets
• 2:08 pm: started mopping with IPA wipes
• 2:17 pm: finished mopping with IPA wipes
• 2:18 pm: changed sticky floor mats
• 2:19 pm: started particle count
  • Zone 3:
    0.3 u: 3990
    0.5 u: 1080
    1.0 u: 374
• Zone 4:
  0.3 u: 540
  0.5 u: 207
  1.0 u: 0

• I was able to plot the first graph for a result between the six different positions on the screen, for now we can see the behavior of the heater temperature in a Gaussian graph with combination data between the six files.
• To do: Tyler gave me some ideas today to improve the plot. So I'm going to change the code to have insulation on the values for just the heater ("insulation") and I'm going to plot after this insulation data as well I'm going to get more data and compare with more data for the same position.
• I was using the data than I got last week and I shared on Elog (151) and we can see on this quote

• I collected data to plot a calibration with the heater. I took measurements with current and temperature (the thermocouple - thermometer) to compare with the FLIR measurements.
• I made a plot with this data and we can see how temperature vs current behaves. Note: This data I measured manually.

• I noticed that these measurements have some issues with the weather on different days. We can see in the photo attached below how different the temperatures are on different days, I took the data with the same procedure every day, but we can see the differences between them.
• To Do: I will do a new data collection using FLIR and thermocouple at the same time to plot comparison between both.

• Today I tried get data the heater with the black screen but doesn't looks possible have just one "energy" point straight to FLIR camera. Tyler and I tried different current and temperatures but keep very bad data. I attached a snap below.
• I attached a photo about the new setup below. The FLIR is in the most close point possible/safety with the heater. The heater is very close to the black wall but is not touch the screen so is safety.

The insulation on the lid of the vacuum chamber has some discoloration and it may be wise to place a sensor closer to this spot in future bakes.

Started to cool down the chamber today. Final temperature readings of the chamber were 146C and 91C for the body and cross respectively.

General information about the lab facility.

1. Changed sticky floor mats, because close to entrance the cleanroom, both sticky floor had a many died ants on top.
2. The light on top of the internet cable bridge is burned out.. I just saw this today but I am not sure if was like this before.
3. The ant bait traps seem very efficient and right now only a few ants are running around in the lab, most are dead in the bait traps, so probably in a day or two we can change those bait traps.

Aiden 3D printed a new bridge for the heater and I installed the new bridge yesterday.

I started collecting data to plot a calibration with the heater. I'm doing measurements with current and the thermocouple (thermometer) to compare with FLIR measurements and have a good calibration.

Checked on the vacuum system and it looks like it will either need to be increased in temperature or baked for a longer time. The main body is at 146C while the cross is at 91C.

In response to reports that ants have been observed in the lab, I placed five ant bait traps around the room today. Each is sitting on the floor on top of a piece of aluminum foil, in areas unlikely to be inadvertently stepped on. They contain liquid which will spill out if picked up, so please take care not to disturb them.

Update: After seeing the strong response to the first set, I redistributed them to the hottest spots and added one more trap.

Checked on the vacuum system today to change the PID controls back to their default values in order to try and get the temperature of the cross in front of the turbo pump higher. Currently it is sitting at 90 degC before changing the controls. While the main body is at 146 degC.

Will update again tomorrow on new equilibrium with the default PID settings.

Checked on the system today.

The flange on the turbo pump has reached an equilibrium temperature of 87 degC when set at 150 degC. While the main body of the chamber has reached an equilibrium temperature of 142 degC.

The temperature of the flange connecting to the turbo pump after reaching equilibrium is 74 degC. This means that it is safe to proceed with raising the temperature from 120 degC to 150 degC.

Raised the set temperature of the chamber from 120 degC to 150 degC in 15 deg steps.

Cao suggested using the project without the reflector and mask because in this case we probably got good images around the screen. So I started this yesterday and today I started to get some data to see the stabilization position and check how the parameters fluctuated. I was looking and taking snaps for an hour and a half. I'll repeat this one more time to make sure we have enough data to do analysis.

To do: The next step is to start collecting data by moving the camera FLIR and covering all six positions on the screen (2x3). Also Aiden is on hand to help and is going to make a new 3D print bridge to have good heater support.

I attached a image for the new configuration below and a snap data.

Pressure Measured Before Removing Gauge 2.31 E-7 Torr.

Went in and turned on the heating tape in increments of 30 degC until 120 degC was reached. I will let it equilibrate over night and then asses whether or not the chamber can be raised to 150 degC without having the flange to the turbo pump reach over 120 degC as it is not recommended for that flange to be any hotter.

If it can safely be raised to 150 degC, then only 2 days of baking is necessary. If 120 degC is the bake temperature, a week will be needed.

cleaning cleanroom and particle count

• 12:00 pm: started particle count
  • Zone 3:
    0.3 u: 2826
    0.5 u: 457
    1.0 u: 166
  • Zone 4:
    0.3 u: 457
    0.5 u: 83
    1.0 u: 41
• 12:17 pm: began surface check and wipedown. NOTE: found a few ants crawling up the metal table frame and on the desk
• 12:29 pm: started vacuuming the floor
• 12:45 pm: Finished vacuuming the floor
• 12:46 pm: Started mopping the floor
• 12:52 pm: Finished mopping the floor
• 12:55 pm: Started cleaning the buckets
• 1:02 pm: Started mopping with IPA wipes
• 1:11 pm: Finished mopping with IPA wipes
• 1:12 pm: Changed sticky floor mats
• 1:14 pm: started particle count
  • Zone 3:
    0.3 u: 2577
    0.5 u: 457
    1.0 u: 166
  • Zone 4:
    0.3 u: 457
    0.5 u: 41
    1.0 u: 0

Cao and Aiden put the RGA back on to the chamber and measured the outgassing rate after the chamber has cooled down from its first bake. The figure attached shows the RGA measurements with the Argon leak open.

Also put the Full Range Gauge #2 [RGA line] back onto the system to measure the pressure and got a reading of 2.78 E-7 Torr. We believe it is actually lower as the chamber temp is still at 28 degC rather than the 24 it was previously measured at. The gauge also may have needed more time to equilibrate.

• I was able to work on the python code to do analysis on the FLIR-Reflector data.
• I could plot images of total area (Tyler help me on that) with csv file and also could have isolation area for triangles. I have attached examples below. Just for now the images are of different data, so there are some differences in the shapes.
• I'm working on getting a complete analysis code to work with the different positions of the triangles and to be able to do out the statistical analysis.
• Also we keeping have problem to get good data if when we move the camera or the reflector on horizontal or vertical position. I am working a some ideas for that.

To access and control the Red Pitaya using Python locally on a machine within the local network, one should follow these steps:

1. Start the SCPI server. This is achieved by first log onto the Red Piatay page

   rp-xxxxxx.local/ 

2. Go to Development >> SCPI server and turn the server on. (Note : The server is currently running)
3. Communication with Red Piataya is done through PyVista, install PyVista with:

    sudo pip3 install pyvisa pyvisa-py 

   This has been installed on Chimay. Ensure that you have pip3 install, if not, you can install it using:

    sudo apt-install python3 pip 

4. To start talking to the RedPitaya, ensure you have the scipt

    redpitaya_scpi.py 

   in your local folder. This is the standard class that you will import to your code to establish connection with the Red Pitaya. This code can be found in directory

    ~/RedPiatya 
    or this link
   

After leaving the the chamber to bake at 120 deg C from Thursday 3:41 pm. Today I started to cool the chamber down to room temperature at 11:30 am (total bake duration: 91 hours 49 minutes). Ideally, this process should be ramped down slowly, approx. 6 degree per hour. However we had no ramping function with out controller. The only method to tune this cool/ heat rate is to tune the PID parameters, which are:

1. Pb : Proportional band, this quantity is inversely proportional to the P-gain
2. ti : Integral time. Increasing integral time makes the output response slower to error, thus the opposite effect of increasing integration gain
3. td : Differential time

1. Pb : 50
2. ti : 100 s
3. td : 25 s

1. Pb : 200
2. ti : 800 s

Today, I was able to make some adjustments to the FLIR camera angle, suggested by Dr. Richardson, and we got small possible movements keeping the same pattern in the shapes of the triangles. I have attached photos below. I was able to move left and right as well as up and down and it worked in four points that I marked on the table.

The only problem is that it only worked on a part of the screen, if I try to place it farther to the right or to the left, we are back to the same problem as yesterday.

[Pamella]

Updates: Problems with the emission intensity and python code.
• Yesterday I was working on get data from FLIR reflector but unfortunately we got some problems:

1. I realized than if I move the reflector a to left or right the screen doesn't get data very well(I attached a photo below). This is a problem because our idea is have the same type of emission every part on screen. Tyler and I worked to tried fix that but don't had success.
2. Dr. Richardson gave me the idea to move the FLIR camera to left or right (The same happens if I move up and down) and keep the refletor on the same position every time but unfortunately we got the same problem, the screen doesn't get data very well(I attached a photo below). Now I am working to tried fix that.

• Also I was able to work on the code to isolate the triangle shape for analyzes, I attached the image for that below.

Summary : We resolved problems with heaters tripping power and were able to proceed with chamber baking

1. Circuit connection adjustment

After yesterday elog 137, today we resolved most of these issues. After Jon contacted Facilities, the LP3B 6 circuit was reset and the cleanroom filter & light panels resumed to work as normal.

Regarding the connection of the heaters. we made the following adjustments:

• High-temperature controller powering lid + upper volume heater: connect to LP3B 8 circuit (clean room sides, 2 outlets)
• High-temperature controller powering bottom + lower volume heater : connect to LP3B 4 circuit (workstation side, 2 outlets)

2. Replacement of vacuum nipple insulation

We had also received new insulation pieces from Worbo today to replace the existing insulation with the new ones (see images). These cover the 2 4" tubes (for 6" flanges ) and the 4 1.5" tubes (for 2.75" flanges). The new insulations fit perfectly on these tubes. I also placed all insulation taken off from the last elog back onto the chamber ( these are insulations for the pumps and RGA lines).

3. Baking

• Starting set point: 40 deg C
• Step increase: 10 deg C up to 80 deg C, 5 deg C from 80 deg to 120 deg C
• At each step, the temperature readouts show approx. 2.1 deg C overshooting, wait to settle back to approx 1.5 deg C overshoot before increase the set point again

The temperature of the chamber reached as stable 120 deg C without any power issues at 3:45 pm. I waited another 15 minutes to verify its stability and the official baking duration started at 4:00 pm Jun 29 2023. Since we are baking at 120 deg C instead of the standard 150 deg C for Aluminium, the duration for the bake will be over three days until Monday morning, upon which we will slowly ramp down the the temperature.

With the new change in wiring configuration described in elog 136, we tried to power up the heaters for baking the vacuum chamber again.

1. Evidence of smoke originating from CoolSkin insulation

We then removed most of the CoolSkin insulation on the Pump and RGA lines ( apart from the one around the flexible bypass line connecting the two ) (see image Pumpline_afterRemoveInsul and RGAline_afterRemoeInsul) . Upon removal of the insulation, we noticed that the insulating foam melted onto the heating tape (see image MeltedInsulation1 and MeltedInsulation2). This is the first indication that the smoke had most likely coming from the insulating foam itself

Once we started baking, upon reaching 80 degree range. We observed no smoke at the location that we removed the insulation. However, We observed smoked coming from underneath the insulation around the flexible pipe, and not from the velcro areas.

2. The heaters still trip our power

TL;DR:

Full version:

20 June 23:

• Turn off heater (short term testing) Close valves to RGA line and main volume. Pressure (Torr) readout:
  • Gauge 1 (main volume): 3.43E-6
  • Gauge 2 (RGA line): 2.61E-6
  • Gauge 2 (pump line): 3.8E-4
• Turn off turbo pump, let vacuum line vent
• Connect high temperature control unit to main power, power up, set setpoints:
  • Temperature setpoint: 150 deg C
  • High temperature setpoint (to switch off) : 175 deg C
  • Hysteresis: 10 dec C
• change setpoint of PID control unit to 150 dec C, with high alarm set at 165 deg C
• Connect power output of high temperature control units to PID temperature control units, ensuring both are off
• Turn off scroll pump
• Replace Pirani gauge in front of turbo pump with blanks (see image)
• Pump the vacuum line back down
• Open up valves and wait until pressure of full system drop back down to 1E-6
• Install the high temperature controller thermocouples onto the chamber (see images):
  • One thermocouple is installed on the other side of the cross before the turbo pump
  • One thermocouple is installed on the main volume next to the PID controller RTD
• Attempt to remove electronic box and magnetic shield of full range gauges:
  • Electronic box is easily removed with an Allen key
  • Magnetic shield cannot be removed since the gap between the vacuum flange and the gauge bolt is too short for a spanner to go in. This is mainly due to the bolt washers are in the way (see images)
  • To remove the magnetic shield, the main volume has to be vented and the gauges need to be readjusted.
• Attempt to power heaters (but only heat to 80 deg C):
• Leaving the gauges intact, the high temperature controller + PID controller are turned on to test heating the chamber
• At this point, both of the high temperature controllers are connected to the same power strip (Vacuum chamber end of the table)
• After heating up to 65-70 deg C range, the powers turned off on both controllers + the lights on one end of the table
• Upon inspection, the power strip has turned itself off, I don't know what the model of the power strip but we should check its current limit
• For a quick test, I connect one of the two heater controlling system to the power board on the work desk while leaving the other running off the same power strip: The heaters appeared to be function ok and able to reach 80 deg C, at which point I turned it off and left for the day

21 June 23:

The goals of today was to remove the electronic boxes and magnetic shields on full range gauges to enable high temperature bakeout

• Upon returning to the lab, the gauges readout of vacuum pressures were:
  • Gauge 1 (main volume): 3.31E-7
  • Gauge 2 (RGA line): 3.40E-7
• Venting the both main volume and RGA line
• Remove the two full range gauges from their flanges
• Electronic boxes and magnetic shields were removed according to the gauge manuals (see images)
• Mount the gauges (with only its probing volume) back onto their respective flanges, ensuring that the flange washers do not block access to the magnetic shield screws
• Only remount magnetic shield + electronic box for one gauge (gauge 2: RGA line) for monitoring chamber pressure
• Turn on scroll pump and let the chamber pump down
• Rearrange heater controller connections while waiting for pumping down:
  1. Controllers for bottom + pump & RGA line heaters remain the same: connected to power strip on vacuum end of the table
  2. Controllers for lid + upper chamber main volume: connected to power strip on clean&bake end of the table
• Once the pressure readout by gauge 2 reached 3 Torr, the turbo pump was turned on and left to run for 45 minutes
• Upon returning to the lab, pressure on gauge 2 read 5E-6 Torr and was still decreasing
• Disconnect the ethernet cable to gauge 2, remove its electronic box and magnetic shield
• Turn on heater controller units and let them drive the heaters to get up 150 deg C
• At 95 degree range, I could see smoke at some locations, mainly the RGA and pump lines where the insulation do not fit properly and the velcros are likely to be overheated
• Upon reaching 90 degree range (measured by sensors), the powers turned off on both sides of table (including heaters, lights and scroll pump)
  • Turn off both heaters controllers and unplug them from power strip. Attempt to switch the power strip back on but nothing happened
  • It is now not the power strips problem and must be further down the line from outside the tent, most likely the power supply that these strips connected to: What is the power supply model + current limit?
• The heater controllers left unplugged, I temporarily plugged scroll pump to the desk power strip so it can still run