[Yuzurihara, Ishikawa]
During the lockloss investigation of 2024/10/08 - 2024/11/22, we found an average of 1~2 times transient noise of the PRM(K1:VIS-PRM_TM_WIT_P_DQ, K1:VIS-PRM_TM_WIT_Y_DQ) at a few seconds (about 2s, 3s, 6s …) before the lockloss. We can see a similar transient at PRM coil signals (K1:VIS-PRM_TM_COILOUTF_H1_OUT16, K1:VIS-PRM_TM_COILOUTF_H3_OUT16). We also checked the QPD signals, but this transient noise appeared only in K1:VIS-PRM_TM_OPLEV_TILT_SEG1_OUT_DQ. The SEG1 seems to have the trouble.
We are not sure that this transient noise causes lock loss because this transient noise appeared very frequently. We will check the behavior of the PRCL error and feedback signals when the transient noise appears.The detailed plots can be seen in JGWdoc.