Mon Jul 1 15:19:42 2024, Cynthia , Update, Interferometer Simulations, O4 and O5 mirror cavity scans with thermal effect
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Thu May 15 12:03:41 2025, Xuesi Ma, Infrastructure, Electronics, Notice
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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. |
Tue Apr 11 13:15:40 2023, Cao, Infrastructure, Clean & Bake, Nitrogen gas tank replaced
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The nitrogen gas tank has been replaced with a new unit. The new tank is ultra pure nitrogen (>99.9% nitrogen).
The new tank has been placed and secured to the rack where the old one is; cap is removed and regulator is reinstalled onto the new tank. |
Fri Feb 10 16:34:45 2023, Huy Tuong Cao, Infrastructure, Clean & Bake, Nitrogen gas tank ready to use
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Cao,
Today I fixed the final bit related to the nitrogen gas tank, which is to apply sealing tape to M-NPT connector of the hose to prevent
leakage (file: AirGunSealed.jpg)
After application of the tape, no audible leak can be heard from connection between the hose and the air gun.
The general operating procedure for the gas tank is as following:
- Turn the regulator (blue handle) anti-clockwise still it's loose
- Turn the valve on nitrogen as tank anti-clockwise, immediately the RHS meter of the regulator would jump to approx 2000 psi. This is the standard pressure for high pressure gas tank
- Turn the regulator clock-wise slowly until the pressure one the LHS meter face reads approx 60 psi. This is sufficient for drying parts with. At this point, the flow pressure still should register zero
- Press the trigger on the air gun, a high pressure air flow should come out and the flow meter should increase
- When finished, close the gas tank valve, turn the regulator anti-clockwise, then press the air gun trigger to release gas left in the hose/gun
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Fri Jul 26 17:25:42 2024, Jon, Infrastructure, Computers, New workstation ws4 installed in 1129
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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. |
Thu Jun 20 18:01:11 2024, Jon, Infrastructure, Computers, New workstation ws3 in 1129
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I have repurposed a spare Intel NUC to serve as the first of two planned workstations in 1129. Today I set it up with a fresh installation of Debian 12.5, assigned it the static IP address 192.168.1.15, and installed the LIGO CDS workstation packages. It is assigned the host name ws3.
Temporarily, the mouse is borrowed from ws1 in 1119. We need to order another mouse as well as a 25-ft Ethernet cable for connecting the workstation to the 1129 switch, via the ceiling. |
Wed Jun 26 15:33:41 2024, Jon, Infrastructure, Computers, New workstation ws3 in 1129
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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).
Quote: |
I have repurposed a spare Intel NUC to serve as the first of two planned workstations in 1129. Today I set it up with a fresh installation of Debian 12.5, assigned it the static IP address 192.168.1.15, and installed the LIGO CDS workstation packages. It is assigned the host name ws3.
Temporarily, the mouse is borrowed from ws1 in 1119. We need to order another mouse as well as a 25-ft Ethernet cable for connecting the workstation to the 1129 switch, via the ceiling. |
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Wed Aug 9 11:32:56 2023, Jon, Infrastructure, General, New power cables
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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. |
Fri Apr 25 19:18:10 2025, Luke , Update, Scripts/Programs, New optimization plots 
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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. |
Sun May 11 19:36:42 2025, Luke , Update, Scripts/Programs, New optimization plots
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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. |
Tue Jun 27 15:18:26 2023, Pamella, Update, FLIR, New data collection 
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Yesterday, I did a new data collection. I could get a better data in this time and I realized than I need use some angle on the reflector for got a better shot. I need do that because the FLIR camera just is able to get the triangle shape for complete if I keep exactly in same line for center point on the camera but for the data now I need move the refletor to go up and go down. So wasn't working very well if I keep the reflector without angle.
Now I am using the refletor with a angle. In the more high part I turn the mask for look the table and in the lower part I turn the mask to look up. I attached a photo below for this configuration.
Also the processes to get the data was the same than I using last time, the only diference is now I just moved the pillar after get data for high position and lower position for the same reference point on the triangle shape.
Note: In most data it is impossible to keep the same parameter for current, voltage and temperature. Most have a small variation but not a big difference. For example: I got the temperature in the first position 46.8 °C and in the second position I got 47.1 °C, it's just an example. It's just so we know that we don't have the exact same parameters all the time. In my opinion this is not a problem because it is just a small variation.
- 09:35 am: Turned on the device (current on). I wanted for 30 minutes before start get data.
- 10:05 am: Started taking snap on position one (Reference point: -0.10, 0.050). Parameters:0.11A,1.7V,46.8°C
- I took four snap on the same position for compare after on data analyzes. I just wanted one minute break between the snaps. I did the same for every position.
- 10:15 am: Started taking snap on position two (Reference point:-0.10,-0.050 ). Parameters: 0.11A,1.7V,47.1° C
- 10:22 am: Started taking snap on position three (Reference point:0.00 ,0.050). Parameters: 0.11A,1.6V,48.1°C
- 10:26 am: Started taking snap on position four (Reference point: 0.00,-0.050). Parameters:0.11A,1.6V,48 °C
- 10:32 am: Started taking snap on position five (Reference point: 0.05,-0.050). Parameters:0.11A, 1.6V, 48°C
- 10:37 am: Started taking snap on position six (Reference point: 0.05,0.050). Parameters: 0.11A,1.7V,47.6 °C
- We can see in the photos attached below every position also I am working in the analyzes.
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Tue Jun 13 21:33:46 2023, Pamella, Update, General, New cabinet for PPI
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[Pamella and Dr.Richardson]
Dr. Richardson installed the new cabinet outside the room for the PPI equipments, and then I wiped all surfaces inside and outside of the new cabinet.
Dr.Richardson and I have finished organizing the PPI within the new cabinet. Also we have new supplies of gloves, and will likely have more supplies for other PPIs soon. |
Fri Jul 14 16:49:42 2023, Pamella, Update, FLIR, New bridge and calibration data
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[Pamella]
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. |
Mon May 13 14:48:27 2024, Aiden, Update, VAC, New Vacuum Chamber Design
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I created a new model for the vacuum chamber based on the ideas from last week's meeting.
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 |
Mon Jul 8 17:01:45 2024, Shane, Update, CDS, New CyMAC internal layout
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[Jon, Shane]
Internal layout of CyMAC has been updated (labeled image attached) to accommodate the replacement of the two ribbon cables. Looking down on the chassis from the front, and going from left to right, the new placement is as follows: BIO card, DAC adapter board, ADC adapter board, DAC card, ADC card. NOTE: As part of ADC-DAC loopback testing, we're disconnecting from the FROSTI readout chassis and using the cables to connect directly from ADC input channels to DAC output channels . Initial testing confirmed functionalility of all 32 ADC input channels and the first 8 DAC output channels. |
Tue May 30 14:51:27 2023, Pamella, Update, FLIR, New 3D mask - Bigger triangles shapes. 
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[Pamella]
Change the 3D mask
- Started removing the old mask in the reflector.
- Started cutting the new aluminum lid for the new 3D mask and assembling in the 3D mask.
- Started doing the new cable connections for the light.
- Started testing the resistance in the new cable connections. The multimeter show us 14.2 Ω.
- Started attaching the mask with the light and the thermometer sensor.
- Started assembling the 3D mask in the reflector.
- Started the initial tests.
- 2:00 pm: Started testing the new mask. Parameters: 1.4 V 0.1A and 27 C
- 2:38 pm: Started taking snap. Final parameters:1.4 V 0.1A and Temperature: 39.9 C
- Started doing some adjustments in the triangles shapes for the futures tests.
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Tue Jul 29 11:27:57 2025, Liu, Update, Interferometer Simulations, Multi-ring FROSTI optimization for A#  
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Tue Aug 12 12:16:21 2025, Liu, Update, Interferometer Simulations, Multi-ring FROSTI optimization for A#
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Multi-ring FROSTI optimization for A# with static polishing |
Tue Jul 25 15:35:14 2023, Shane, Update, Electronics, More chassis moved
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Finished basic assembly of binary input and output chassis today, and moved one to top shelf of work bench. The other is in corner of work bench (image attached). They are delicate, so please do not move them or place anything on top of them. |
Wed May 3 19:03:47 2023, Julian,Pamella and Cao, Physics, VAC, Modify vacuum asssembly and install RGA
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[Pamella, Julian, Cao]
Today we started re-configuring the vacuum chamber components.
Particle count
- 10:45 am : Starting the particle count in the clean room.
- 11:13 am : Finished the particle count in the clean room.
- Zone 3 :
- 0.3 u: 2535
- 0.5 u: 1413
- 1.0 u: 789
- Zone 4 :
- 0.3 u: 457
- 0.5 u: 290
- 1.0 u: 207
Starting the reconfiguration.
- 11:21 am: Started removing up-to-air valve
- 11:30 am: Finished removing up-to-air valve.
- 11:33 am: Started removing calibrated Ar Leak and the elbow.
- 11:35 am: Finished removing calibrated Ar Leak and started assembling the up-to-air valve.
- 11:47 am: Finished assembling up-to-air valve.
- 11:48 am: Started removing magnetron gauge.
- 11:55 am: Finished removing magnetron gauge.
- 11:57 am: Started installing the elbow and calibrated Ar Leak and started removing the RGA probe
- 12:13 pm: Finished installing the elbow and calibrated Ar Leak.
- 12:20 pm: Break for lunch.
- 01:25 pm: Come back from lunch break.
- 01:30 pm: Started removing RGA line.
- 01:39 pm: Finished removing RGA line.
- 01:39 pm: Started removing gate valve [RGA line] and finished removing gate valve.
- 02:00 pm: Started installing gate valve in the new position.
- 02:08 pm: Fished installing gate valve [RGA line].
- 02:09 pm: Checked the screws in the elbow to gate valve. [RGA line].
- 02:28 pm: Finished checking the screws in the elbow to gate valve [RGA line].
- 02:29 pm: Started installing RGA line.
- 02:39 pm: Finished installing RGA line.
- 02:50 pm: Started installing magnetron gauge.(In this part we assembled gauge with the used gasket)
- 03:02 pm: Finished installing magnetron gauge.
- 03:04 pm: Started installing RGA probe [RGA line].
- 03:13 pm: Finished installing RGA probe [RGA line].
- 03:15 pm: Connected the cables to the magnetron gauge.
- 03:20 pm: Started the testing in the vacuum chamber.
- 04:30 pm: Started installing the RGA 200 and connected the cables (power cable and DB9 cable).
- 04:52 pm: Finished installing the RGA 200 and connected the cables (power cable and DB9 cable).
- 04:53 pm: Started testing the RGA connections. Logrus is able to recognize and connect to RGA unit. We are leaving the turbo pump on for a few hours before checking back for pressure readouts.
- 05:00 pm : Starting the particle count in the clean room.
- Zone 3 :
- 0.3 u: 2244
- 0.5 u: 997
- 1.0 u: 207
- Zone 4 :
- 0.3 u: 2993
- 0.5 u: 1579
- 1.0 u: 498
- 05:30 pm : Finished the particle count in the clean room.
- 05:34 pm: Test pressure readout from the gauges.
- Channel 1 : 1.06E-5 mbar
- Channel 2 :8.89E-6 mbar
- Channel 3 :5.0E-4 mbar
- 05:59 pm: Test pressure readout from the gauges.
- Channel 1: 9.09E-6 mbar
- Channel 2: 7.75E-6 mbar
- Channel 3: 5.0E-4 mbar
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Wed May 31 16:18:41 2023, Aiden, Summary, General, Mock FROSTI
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Finished assembly on the Mock FROSTI so it is ready for the fit test at LIGO lab. |
Mon Jul 8 12:26:10 2024, Michael, Update, Interferometer Simulations, Minimizing Astigmatic Effects in the SRC of LIGO
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This is the first look and analysis of the effects of astigmatism in the aLIGO optical layout which can lead to mode mismatch and therefore increased losses into higher order modes. Specifically I am currently looking at measuring the effect of changing the radii of curvature of the SRC mirrors https://docs.google.com/presentation/d/1qhIehqyNukg4g8S2fqfQZz83yr9aB76tEa6fn2J-TrM/edit?usp=sharing |
Tue Jul 29 11:45:19 2025, Maple, Update, TCS, Meeting update
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Sat Feb 24 08:53:38 2024, Jon, Infrastructure, Computers, Matlab upgraded to 2023b on Chimay
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I upgraded Matlab on chimay to the latest stable release, 2023b. From some quick tests, it appears to be in working order. Let me know of any issues. |
Thu Jan 2 17:52:58 2025, Luis, Update, VAC, MR Testing Continuation  
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[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.
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Mon Dec 16 21:32:21 2024, Luis, Update, VAC, MR Testing
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[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. |
Sun Dec 22 20:43:35 2024, Luis, Update, VAC, MR Testing 
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[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.
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Tue Nov 5 09:56:04 2024, Luis Martin, Update, Clean & Bake, MR Bake
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[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.
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Mon Feb 19 14:40:21 2024, Shane, Update, CDS, MEDM screen for FROSTI temp readouts 
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Here's the latest draft of the MEDM screen for the FROSTI heating elements' temperature readouts. Note that the MEDM screen isn't actually this grainy, this just happens to be a photo of the lab monitor's screen off a phone. |
Thu Feb 29 17:16:48 2024, Shane, Update, CDS, MEDM screen for FROSTI T/P readouts
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Here's the latest draft of the MEDM screen for the FROSTI temp and power readouts, now with a button linking to the c1msc file display. Size/color/label are all changeable, if adjustment is needed. Checked in execute mode as well, and it's working correctly. Also noticed that the MEDM file name has been changed to FROSTI.adl, which I'm noting here for future reference. Still in medm_sandbox directory. |
Wed Jun 11 16:33:45 2025, Pooyan, Update, Computers, Luke's ray tracing hosting
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- 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.
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Wed Feb 21 23:15:07 2024, Michael, Update, Interferometer Simulations, Long Shoelaces 1 Layout Created in Gtrace and Fixed Ghosting in Beamsplitter  
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I have created the long shoelaces 1 layout for cosmic explorer using gtrace, a slight modification from the shoelaces 1 layout design. I also modified the simulation code slightly to remove ghosting effects in the beamsplitter. Originally the python code specified that the HR and AR sides of the beamsplitter both have the same transmission/reflection. I modified this to the ideal case of: Refl_AR = 0, Trans_AR = 1. I have attached two images below to show the before and after effect of this modification. |
Tue Feb 6 22:40:25 2024, Michael, Update, Scripts/Programs, Long Crab 1 Design Created In Gtrace 
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Worked on and completed the python code for the simulation of the Long Crab 1 layout for Cosmic Explorer basing off of Pooyan's original work with the Crab 1 layout. From here I'll look into creating the shoelaces layouts. |
Wed Nov 20 12:31:24 2024, Luis, Update, VAC, Leak test RGA Scan after vacuum repairs
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[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:
Connection |
Leak rate (torr) |
Reducing Cross - TP Left |
4.5e-9 (lowish) |
Reducing Cross - TP Right |
6.0e-9 (lowish) |
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Tue Nov 19 17:10:34 2024, Luke , Update, VAC, Leak check  
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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" |
Wed Oct 23 11:48:06 2024, Luis Martin, Update, VAC, Leak Test Results
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[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.
Connection |
Leak rate (torr) |
Tee - RGA |
9.4e-12 (very low) |
Tee - Cal leak |
1.58e-11 (very low) |
Tee - ZLR (2.75"-4.5") |
7.32e-12 (very low) |
ZLR (2.75"-4.5") - Reducing Cross |
6.9e-11 (low) |
Cross - Elbow |
2.34e-11 (very low) |
Elbow - Pressure sensor |
1.96e-11 (very low) |
Cross - Turbo pump (small) |
1.91e-9 (lowish) |
Cross - Gate valve |
1.66e-10 (very low) |
Gate valve - Port |
7.41e-10 (low) |
Port - ZLR (6.0"-8") |
2.93e-10 (low) |
ZLR (6.0"-8") - Turbo pump (large) |
6.15e-11 (very low) |
Port - Pressure sensor |
2.0e-11 (very low) |
Port - Up to air valve |
1.42e-11 (very low) |
Port - Blank |
1.27e-11 (very low) |
Port - Feed through port |
4.59e-12 (very low) |
Lid - Curtain side |
3.09e-11 (very low) |
Lid - Wall side |
4.26e-11 (very low) |
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Mon Nov 20 20:45:16 2023, Aiden, Update, VAC, Leak Test
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[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. |
Tue Jun 6 16:15:09 2023, Peter, Update, VLC Update, Launch Optics for Visible Light Cavity 
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I assembled the first few components of the launch optics for the visible light cavity. Below is an image of the current table configuration, and the image is how the cavity will be oriented on the table. |
Fri Feb 23 15:01:48 2024, Shane, Update, CDS, Latest draft of MEDM screen for FROSTI readouts 
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Here's the latest draft of the MEDM screen for the FrOSTI temp and power readouts. Also, debugged the text readout boxes so they're now correctly reading out the live temperature and power values. |
Mon Dec 23 14:33:36 2024, Tyler, Update, TCS, Latest RIN Measurement Results   
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Attached below are the measurements I took from the FROSTI from 12/18-12/22. |
Tue Apr 4 09:53:37 2023, Peter, Update, VLC Update, Laser intensity/polarization drift measurements
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The set up for the next round of beam characterization measurements has begun. The beam is initially passing through a half waveplate, is split at a polarizing beam splitter, and then stirring mirrors are used to properly aim the beam into photodiodes (not yet installed). This is the current configuration of the set up. |
Thu Apr 6 10:20:43 2023, Peter, Update, VLC Update, Laser intensity/polarization drift measurements
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More optical components were added to the optical set up for laser intensity / polarization drift measurements. Both lenses and both PDs were added to the configuration, as seen in the image below. The beam is already well aligned into the center of both of PDs, and focused nicely by the lens.
Both PD's take BNC connecting cables, and the Red Pitaya takes SMA connecting cables. Since we are currently without a BNC to SMA cable, and we do not want to cut, strip, and crimp what we have, then measurement process cannot proceed until we get the cables. |
Fri Apr 28 11:21:01 2023, Peter, Update, VLC Update, Laser intensity/polarization drift measurements
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The Digi-key cables have arrived, and I have began implementing them in the intensity drift measurements.
There was a slight problem initially in connecting the SMA to BNC cables from the photodiode to the red pitaya, since the red pitaya was way on the other side of the lab. Cao and I connected the red pitaya to a new ethernet cable that extended far enough for the red pitaya to sit comfortably on the breadboard with the optics.
Right now the PDAs are not connected to the red pitaya. I have connected them to the oscilloscope in order to read out how much voltage they produce upon incidence of 532nm laser light. This was done in order to make sure that they do not surpass the limit of the red pitaya (+-1V). I have not acquired a value for the readout voltage of the PDAs since I had to go to class. I will gather this preliminary data soon. |
Mon May 22 16:43:28 2023, Peter, Update, VLC Electronics, Laser intensity/polarization drift measurements  
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In order to fully analyze the polarization data taken last Thursday, I needed to convert the signal output (which is in volts) to power (units of watts). I used the power meter to accomplish this. Keeping the exact same configuration of PD's and beam splitting, opened the red pitaya's oscilloscope package. I then took the power meter, and held it in front of the PD to measure the amount of Watts at each PD. I then wrote down the corresponding voltage being seen in the red pitaya. I took 5 sets of measurements for each PD to get experimental accuracy. I then used a simple y = mx + b fit to find out the constant m that converts the input wattage into voltage. For the s polarization, the conversion factor is 0.83. For the p polarization, the conversion factor is 1.12. I then used this data to plot polarization angle as a function of time, and the relative intensity drift as a function of time. The plots are shown below. The physical meaning of the polarization angle is shown in the unit circle diagram below, in which P is the total power. |
Wed May 24 14:28:26 2023, Peter, Update, VLC Electronics, Laser intensity/polarization drift measurements   
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I went in and took polarization drift data for 16 hours. The run started at 6:08pm and finished at 9:15am the next day. The four plots below are the same plots shown for the 2 hour collection and previous trials, except they extend to 16 hours. The only one that is different is the Power vs. Time graph. This is a graph of the actual incoming power of the laser (as opposed to the signal voltage that the PDA's output into the red pitaya). This was done using the calibration factors of the respective PDA's and as we can see, since there is a difference in the calibration factors between detectors, there is a difference in the power that's coupled into S and P polarization. |
Sat Feb 4 17:01:03 2023, Peter, Update, VLC Electronics, Laser Data 
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Peter and Ryan took laser beam data. Configuration: 100mm focal length lens is ~100mm from lens. 150mm focal length lens is ~200mm from first lens. Beam waist is ~420mm from second lens.
Beam waist is very small still. Had to input large amounts of error in data collection. Took width data successively at points near waist and at >= Rayleigh range. Plots are shown below.
Key points:
Took a while to figure out optimum configuration for lenses to be placed so that an accessible beam waist could be obtained.
Beam waist is still very small. May need to do an ABCD calculation to see if there is anything bigger that can be obtained. |
Wed Mar 8 18:35:52 2023, Pamella, Update, , Lab cleaning
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Today Pamella finished cleaning of the cleanroom, starting with the HEPA vacuuming, mopping and clearing all floor with IPA wipes.
Also Pamella and Julian finished cleaning of lab floor, starting with the HEPA vacuuming and mopping.
Shane and Pamella wiped down every surfaces of the laser table, computer table and the table with the vacuum pieces inside the cleanroom.
Shane, Peter, Tayler, Pamella and Julian then wiped down every surface of the laser table outside the cleanroom. We wiped the main tabletop as well as the legs and all parts for the table. We wiped the computer desk, the boxes, the cabinets and every part outside the cleanroom. For now we finished the lab cleaning. |
Tue Apr 11 17:56:15 2023, Pamella, Update, General, Lab cleaning
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Today Pamella and Julian finished cleaning of the cleanroom, starting with the HEPA vacuuming, mopping and clearing all floor with IPA wipes. Also we wiped down some surfaces of the blue table, computer table and the top of chamber. |
Mon Jul 7 17:44:04 2025, Tyler, Update, General, Lab Organization  
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[Tyler, Pooyan, Ma, Cece, Luke, Luis, Christina, Maple]
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. |
Wed Nov 8 17:55:49 2023, Jon, Update, General, Lab Clean-Up Day 1
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[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. |
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