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Reports until 10:40, Friday 04 October 2024
H1 OpsInfo (SQZ)
sheila.dwyer@LIGO.ORG - posted 10:40, Friday 04 October 2024 - last comment - 08:52, Wednesday 08 January 2025(80461)
OPO temperature adjustment instructions

Because we moved the OPO crystal position yesterday, 8045, the crystal absorption will be changing for a few weeks, and we will need to adjust the temperature setting for the OPO until it settles, as Tony and I did last night. 80455.  Here are two sets of instructions, one that can be used while in observing to adjust this, and one that can be done when we loose lock or are out of observing for some other reason. 

For these first few days, please follow the out of observing instructions when relocking, if this hasn't been done in the last few hours, and please try to do it in the last few hours of the evening shift so that the temperature is close to well tuned at the start of the owl shift.

Out of observing instructions (to be done while recovering from a lockloss, can be done while ISC_LOCK is locking the IFO) (screenshot) :

In observing instructions:

Both the OPO temperature and the SQZ phase are ignored in SDF and can be adjusted while we are in observing, but it's important to log the times of any adjustments made. 

Changes made to make this easier (Thanks Corey for beta testing the instructions):

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camilla.compton@LIGO.ORG - 08:52, Wednesday 08 January 2025 (82177)

Update to the In observing instructions:

Both the OPO temperature and the SQZ phase are ignored in SDF, but it's important go out of observing for the change and to log any adjustments made. 

  • To adjust the temperature in full lock, go to the purple SQZ_SCOPE button and choose the OPO temp scope, adjust the OPO temperature to maximize CLF_REFL_RF6_ABS (the green trace). 
  • After doing this it might be necessary to adjust the SQZ PHASE, which can be adjusted in steps of 5 degrees or so.  Set this to maximize the squeezing level, which you can do by watching the DARM FDS dtt template.  It is available from the SQZ DTT purple button, or on NUC33.  It is easiest to adjust this for high frequency squeezing (around 1kHz), this should get you close to good squeezing at 100 Hz. This step isn't need anymore as the SQZ_ANG_ADJUST servo should take care of this. 
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