KAGRA Logbook

OBS (Summary)

hirotaka.yuzurihara - 16:00 Monday 29 May 2023 (25429)

Operation Shift Summary

Operators name: Ikeda, Yuzurihara

Shift Time: 8-16 (JST)Summary:Check Items:
VAC,CRY,TEMP There was no problem

Timeline

8:00 observation from previous shift time
13:21 lockloss (this is the longest lock during O4a : 21.6 hours)
14:23 For one hour, LSC_LOCK guardian can’t lock the interferometer. It stops at LOCKING_OMC_FOR_PRFPMI. We started the alignment of OMMT2T QPD and OMC according to the manual.
14:37 OMC alignment done. During the record of the good oplev values, we faced the error on the INITIAL_ALIGNMENT guardian. (I attach the error message. The channel name to record good oplev value is incorrect.) On the slack and zoom, we communicated with the developer and solved it by YamaT-san.
15:23 new guardian code was loaded.
15:24 requested observation state to LSC_LOCK guardian
15:43 reached observation state
16:00 still in observation

Non-image files attached to this report

error_message.txt

Comments to this report:

takafumi.ushiba - 17:33 Monday 29 May 2023 (25431)

I checked why OMC cannot be locked and found that GRY was locked with TEM10 at that time (fig1).
Since SR3 moves a lot due to ADS if GRY is locked with TEM10, it might cause the misalignment to OMC, which results OMC lock difficult.

To avoid this situation, I set a threshould for relocking with TEM00 in LOCKING_ALS state in ARM.py.
This threshould should be slightly lower than the maximum TRY signals with TEM00 and slightly higher than the maximum TRY signals with TEM10.
Current threshould worked well for a while but probably it doesn't distingish TEM00 and TEM10 completely.
So, if we slightly increase the threshould for GRY, this OMC lock trouble might be avoided.

Since I have no time to check how much TRY signals at that time, I have no idea how much increase is sufficient and not too much.
So, if someone will check the values when GRY was locked with TEM10 and when GRY was locked with TEM00 before the TEM10 lock, it is very helpful to decide new threshould.

Images attached to this comment

hirotaka.yuzurihara - 9:05 Tuesday 30 May 2023 (25434)

I did the quick check of GRY when TEM00 and TEM01.

5/29 13:30 TEM01 [image] [ndscope]

5/29 15:50 TEM00 [image] [ndscope]

I added the current threshould (0.55) for GreenY.

Images attached to this comment

25434_1685404640_Screenshot from 2023-05-30 08-57-13.png

25434_1685404794_Screenshot from 2023-05-30 08-58-55.png

tomotada.akutsu - 9:05 Tuesday 30 May 2023 (25435)

Maybe we can have discussion what if increasing the threshold very slightly...