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.

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.

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.

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.

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

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.

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.