We performed the lockloss investigation of 2024-09-11 16:02:02 JST (still ongoing).

memo

• The message of LOCKLOSS of ASC_LOCK was 'PRMI seems to be unlocked'.
• I checked the error and feedback signals of ASC.
  • ndscope -w '(-15, +0.2)' -t '2024-09-11 07:02:02 UTC' /users/Commissioning/templates/ndscope/ASC/DHARD_P.yml
  • There were no signals with the saturation.
• At ~10s before the lockloss, the FM8 of DHARD_P, CHARD_P, DSOFT_P was turned on.
  • After that, K1:LSC-POP_PDA2_RF90_I_NORM_MON started the oscillation and the amplitude decreased. The oscillation frequency is ~0.71 Hz as seen Fig.
• From my eye, there are no strange point related to Xarm (Fig)
• At ~1s before the lockloss, K1:LSC-AS_PDA1_DC_OUT increased three times and K1:LSC-REFL_PDA1_DC_OUT_DQ decreased, as seen Fig. At almost same time, the laser power in trans started the decrease.