Reports until 10:45, Thursday 16 October 2025
H1 ISC
elenna.capote@LIGO.ORG - posted 10:45, Thursday 16 October 2025 (87508)
Moving ETMY beam spot (again)

Since we are still not happy with our buildups, I moved the ETMY beam spot again, following the assumption that this camera was bumped on Tuesday.

Instead of considering the A2L gains or ADS, I just chose to move the spot around by hand to make the buildups better. I did so slowly in pitch and then in yaw. Overall, the final camera offsets are P: -224 and Y: -346. This offsets brought the PRG up to 49.5 and the arm powers up to 380 "kW". I also noticed that this change brought the Y arm power up slightly about the X arm power, which is how it used to be before whatever happened on Tuesday.

Once the cameras converged on these new values, I ran the A2L script. This was a large beam shift for ETMY, so I had to run it a few times to get the script to cross zero for the ETMY lines. I would run it, guess where to go next, and rerun. Sheila pointed out to me that if you scroll up in the script output, it will tell you where it thinks the zero crossing is. I was able to use this to guess the final position. I reran one more time to see the script cross zero on all dofs, confirming that the A2L gains ended up in the right spot.

As a part of this, I was able to test TJ's new version of this script, /opt/rtcds/userapps/release/isc/h1/scripts/a2l/a2l_min_multi_sdf_cleanup.py

His script now does not leave SDF diffs, since it reverts all the tramps and matrices. However, when I cntrl-Ced, only half the lines turned off. It appears that cntrlC only turns off the matrix values for pitch, but not yaw, and it still leaves the clkgains and such in place. So the cntrlC capability needs more work. To get the scrpt to revert everything properly, you still need to let it fully run.

I updated the guardian lscparams to have these new ETMY A2Ls (P: 4.89, Y: 0.78) and camera offsets. I have loaded both the ISC_LOCK and the CAMERA_SERVO guardians.

While these A2Ls suggest that the ETMY spot has not ended up in the same place as before, I do believe this is a good place that gives us good buildups, so I think this is a fine spot to be in.

First run:

Optic DOF Initial Final Diff
ETMX P 3.13 3.13 0
ETMX Y 4.85 4.9 0.05
ETMY P 6.43 6.43 0
ETMY Y 1.37 1.37 0
ITMX P -0.45 -0.45 0
ITMX Y 3.16 3.15 -0.01
ITMY P 0.19 0.2 0.01
ITMY Y -2.75 -2.74 0.01

Second try I cntrl-Ced which sort of worked.

Third try:

Optic DOF Initial Final Diff
ETMX P 3.12 3.12 0
ETMX Y 4.89 4.9 0.01
ETMY P 4.89 4.89 0
ETMY Y 0.78 0.78 0
ITMX P -0.46 -0.46 0
ITMX Y 3.15 3.16 0.01
ITMY P 0.19 0.19 0
ITMY Y -2.74 -2.74 0
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