I performed the lockloss investigation of 2024/10/29 2024-10-29 08:38:10 JST. Although the main causes of the lockloss was not identified, I put some findings on the data around the lockloss time.
Details
- By checking the timeseries using ndscope, there was the transient on K1:VIS-SR2_TM_WIT_{P,Y}_DQ at the -40 s before the lockloss. (Fig)
- I checked the whitened spectrogram of oplev signals. We can see the coincident transient on oplevs for SR2, SR3, ITMY,ETMY, ITMX, and ETMX. (Fig) There was no transient on oplevs for BS, PR2, PR3, and PRM.
- Note that these transients were difficult to see by eyescan. (Fig)
- At the same time, we can see the coincident transient on error signals for ASC (K1:ASC-{D,C}HARD_{P,Y}_IN1_DQ) and the feedback signals (K1:ASC-{D,C}HARD_{P,Y}_OUT_DQ).
- At the almost coincident time (a bit later?), we can see the drift on K1:OMC-TRANS_DC_SUM_OUT_DQ . (Fig)
- From ~10 second before the lockloss, we can see the small drift on K1:ASC-DHARD_P_IN1_DQ, K1:ASC-DSOFT_P_IN1_DQ and relevant QPD signals. (Fig) I'm not sure this is related to the transient signal.
- Related to scattered light
