Reports until 16:47, Friday 13 January 2023
H1 TCS (ISC)
camilla.compton@LIGO.ORG - posted 16:47, Friday 13 January 2023 - last comment - 14:37, Thursday 19 January 2023(66801)
ITMX and ETMX ring heater changes tonight from 8pm.
At 8pm tonight, I'll have a script turn ITMX RH up from 0W to 0.44W/segment and ETMX down from 0.44W/segment to 0W.  Using 'python3 /tcs/common/scripts/power_adj_scripts/ring_heater_on.py ITMX -s 1357704018 -p 0.4'.
Keeping total amount of power in X-arm the same in the hope of avoiding ringing up PIs. 

Tomorrow morning Sheila will log-in and check if we are locked / able to lock with these settings. If not she will turn them back to the nominal (ITMX at 0W, ETMX at 0.44W/seg) as Robert has tests Saturday PM that need a locked IFO. Thank you Sheila! 

Comments related to this report
camilla.compton@LIGO.ORG - 10:31, Tuesday 17 January 2023 (66830)
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We have left the ring heaters in the ITMX at 0.44W/seg, ETMX at 0W settings as the IFO seemed happy and locking over the weekend.

  • We expected "each Hartmann sensor to see a negative thermal lens forming with the characteristic overshoot in the spherical power followed by a relaxation down to a steady-state value after 24-30 hours (LLO15213)". We saw this in plot and longer timescale plot. We stayed locked for 12 hours after the change so will need to compare locks before and after the change to really understand:
    • Overall for locks after and before change, PR_GAIN, KAPPA_C and circulating powers are lower though circulating powers are more similar - plot
  • Both circulating powers dropped, the Y-arm circulating power dropped most (strange as X-arm RH was adjusted?) - plot
  • RF18 dropped nearly 10% then mostly recovers over the next 12 hours - plot
Images attached to this comment
camilla.compton@LIGO.ORG - 12:54, Thursday 19 January 2023 (66887)
Link

Attaching ndscope plots where circulating powers are visible.

Images attached to this comment
daniel.brown@LIGO.ORG - 14:37, Thursday 19 January 2023 (66893)
Link

Attached are the demodulated frequency injection lines from this RH test and several days of locks afterwards. This RH change made the 25 and 4500 Hz coupling worse  but did improve the 201Hz. Although around 200Hz there is quite a lot of  structure in the frequency noise coupling so unsure how much weight should be put on the 200Hz demodulation line as we could just be seeing this zero feature more around.

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