Reports until 09:28, Tuesday 03 September 2024
H1 SQZ
sheila.dwyer@LIGO.ORG - posted 09:28, Tuesday 03 September 2024 (79877)
SQZ not seeing RF6 MHz this morning

Sheila, Naoki, Daniel

Overnight, the OPO was scanning for about 5 hours, during which time the 6MHz demod was seeing flashes from the CLF reflected off the OPO.  This morning, we still see DC light on the diode, but no RF power on the demod channel.  There aren't any errors on the demod medm screen.

We did a manual check that we have nonlinear gain using the seed, (we can't use the guardian because of the RF6 problem), and it seems that we do have NLG, so the OPO temperature correct.

Daniel found that the CLF frequency was far off from normal (5MHz), because the boosts were on in the CLF common mode board.  Turning these off solved the issue.  We've added a check in the OPO guardian in PREP_LOCK_CLF to check if this frequency is more than 50kHz off, if so it will not return true and will give a notificiation to check the common mode board.

 

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