/ligo/home/camilla.compton/Documents/sqz/templates/dtt/20250819higher_order_modes.xml screenshot attached. Elenna opened POP beamdiv.
| Type | Time (UTC) | Angle | DTT Ref | Notes |
| SQZ | 15:30:00 - 15:35:00 | (-)133 | ref 0 | |
| FDS Mid - SQZ | 15:37:00 - 15:39:00 | (-)111 | ref 1 | At 4dB ASQZ |
| FDS Mid SQZ, SRM YAW -1urad (offset -0.3) | 15:47:00 - 15:49:00 | (-)108 | ref 2 | Made better today and in 86363 |
| Mid SQZ, , SRM YAW -1urad, +8cts DHARD YAW | 15:51:30 - 15:53:30 | (-)108 | ref 3 | No change at 5 or 10kHz |
| Mid SQZ, , SRM YAW -1urad, CAM3Y -1count | 16:04:30 - 16:06:30 | (-)108 | ref 4 | Loop takes ~5 minutes to converge, buildups worse. No change at 5 or 10kHz. |
| Mid SQZ, , SRM YAW -1urad, CAM3Y +1count | 16:15:30 - 16:16:30 | (-)108 | not taken | Builds-ups same as normal. No change at 5 or 10kHz. |
| Mid SQZ, , SRM YAW -1urad, SRM PIT +2urad (offset +0.6) | 16:23:00 - 16:25:00 | (-)110 | ref 5 | Buildups worse, saw 5kHz was a little worse at 5kHz with +0.3 so went further. DHARD PIT started to grow at 1Hz. |
| Mid SQZ, , SRM YAW -1urad, SRM PIT -1urad (offset -0.3) | 16:27:00 - 16:29:00 | (-)107 | ref 6 | 5kHz better |
| Mid SQZ, SRM YAW -1urad, SRM PIT -2urad (offset -0.6) | 16:30:00 - 16:32:00 | (-)106 | ref 7 | 5kHz slightly worse |
| Mean SQZ | 16:35:00 - 16:37:00 | N/A | ref 8 |
camilla.compton/Documents/sqz/templates/dtt/20250818_SQZdata.xml and attached.| Type | Time (UTC) | SRCL Offset | Angle | DTT Ref |
| FIS SQZ | 16:42:30 - 16:45:30 | -382 | (-)124 | ref 1 |
| FIS SQZ | 16:48:30 - 16:51:30 | -200 | (-)153 | ref 2 |
| FIS SQZ | 16:58:30 - 17:01:30 | 0 | (-)224 | ref 3 |
| No SQZ | 17:02:30 - 17:05:30 | -382 | N/A | ref 0 |
Took above data at NLG of 16.0, checked and improved the NLG after data taken 76542.
| OPO Setpoint | Amplified Max | Amplified Min | UnAmp | Dark | NLG | Note |
| 80 | 0.108523 | 0.00199724 | 0.0067894 | -1.22e-5 | 16.0 | Without Optimizing Temp |
| 80 | 0.154115 | 0.00199724 | 22.7 | After Optimizing Temp |
I think we like these SRC ASC offsets, so I set up the guardian to keep them. While the overall effect is minimal, there was a small increase in the buildups that was repeatable: we switched these offsets on and off a few times as we were commissioning today and the buildups got slightly worse when they went off and slightly better when they went on. I tried to process the FIS data, and I think it shows that the overall change in the SRCL offset is minimal, but maybe someone else can confirm. Similarly, the calibration report show the fit of the sensing function is very good in the current model.
Now the guardian engages these SRC ASC offsets in the LOWNOISE_ASC state.
I have attached the results (plot one and plot two) from the FIS measurement, and the fit indicates that our current SRCL offset is fine (I think that's the correct interpretation here).
Here is a trend of the buildups and SRC ASC offsets (pitch and yaw are right on top of each other in the bottom plot). The plot shows that the buildups increase when we add these offsets and decrease when we disengage these offsets.
The calibration report is linked in this alog, and shows that the calibration model is still very good. (There are some strange errors in the report generation, but they are unrelated to this change).
Here is a more to-the-point executive summary of what these results today are indicating:
- the lower frequency mode seems to be most effected by yaw SRM offsets
- the higher frequency mode seems to be the most effected by pitch SRM offsets
- DHARD pitch and yaw offset seem to have no effect on these modes
- Y-arm yaw camera offsets (effectively a DSOFT offset) seem to have no effect on these modes
- stepping both up and down by 1 ct camera offsets also made the buildups worse
A large positive SRM pitch offset caused a growing 1 Hz oscillation in DHARD pitch as well. I'm not sure what to make of that yet, but I wanted to re-emphasize for future moves.
Since we are seeing an improvement in the buildups when adding SRM offsets, I think some of the prevalence of these modes could be related to some uncontrolled AS 72 offset which is changing the SRM alignment offset. We reran dark offsets when coming back from the vent, so the dark offset change on AS 72 could be effecting the SRM alignment in some way.