Reports until 21:47, Thursday 09 May 2024
H1 SQZ
sheila.dwyer@LIGO.ORG - posted 21:47, Thursday 09 May 2024 (77746)
pump polarization adjusted, TTFSS beatnote threshold decreased again, Squeezer seems like it should be OK

The pump ISS would not lock, it seems that the pump rejected polarization in HAM7 has been trending upward for 10days.  I adjusted the half and quarter wave plates at the input of the fiber and got the rejected power down to 23 uW, with 22mW launched into the fiber.  This probably could have been better adjusted, but each time I moved the pico I was having to wait for the PMC and SHG to relock so I decided this is good enough for tonight.

The second attached screenshot shows some trends related to the beatnote dropping.  The powers into the box all say they have been stable, and the power on the beatnote PD also seems stable,  so I'm not sure why the reported beatnote strength is falling.  The current beatnote level does seem like it's enough for the TTFSS to lock without an issue.  I've reset the lower limit to -50, and right now the beatnote strength is increasing again to -7dBm. 

It seem like if the IFO get relocked the squeezer should work, so this would be better than no squeezing for tonight.

Images attached to this report