Elli, Nutsinee
Following LHO alog17941 (PSL accelerometer detected 1Hz glitches) and LLO alog17844 (1Hz peak seen in a magnetometer). Elli left the HWSX camera on from the night of May 16th until the morning of May 18th. I have compared and attached the spectrum from two lock stretches where the HWSX camera was turned on (May 17th 12:00:00 UTC) and off (May 15th 12:00:00 UTC). There's no evidence of HWS camera at the corner station coupled into DARM at ~45 Mpc.
The concern I believe is that this 1Hz comb may be the cause of the 1Hz signal that was seen on the AOM's of the CO2 laser systems see LLO alog 16873. This is not the most pressing issue at this point in time I am of the understanding because the AOMS are not currently used for intensity stabilization of the CO2 lasers, but it is something that is wanted in the near future.
The HWS in the corner station do not cause a 1 Hz feature in the spectrum, they cause glitches once per second. It's not easy to recognize in a spectrum, but very clear in a spectrogram with 1/4 sec FFTs and overlap of 0.9; see Josh's alog. Attached are two spectrograms of the ITMX GS13, the first from the time with the HWS off and the second with it on. The glitches are clear. The third attachment is DARM, where there's no evidence of the glitches.
