[Ma]

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

[Ma, Pooyan, Tyler]

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

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

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

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.

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

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=

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.

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 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.

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.

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.

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

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.

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.

Slides

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.

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

[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

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).

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

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