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Reports until 15:36, Thursday 15 August 2019
H1 PSL
jason.oberling@LIGO.ORG - posted 15:36, Thursday 15 August 2019 (51304)
Checked PSL, Changed ISS Ref Signal

As part of the ongoing investigation in H1 locking issues I took a look at the PSL.  I noticed two things:

1) After a lockloss and the resulting disabling of the ISS Second Loop, the Inner Loop Percentage Diffraction was very low, <1%.  This was causing the ISS Inner Loop to in turn oscillate, unlock, relock, and repeat.  I changed the ISS Ref Signal from -2.05 V to -2.02 V.  This brought the Percentage Diffraction back to ~2.4%; we want it between 2% and 3%.  I accepted this change in both the safe.snap and OBSERVE.snap SDF files.  This had no effect on the locking behavior of H1.  *add red herring pic here*

2) As noted previously, the FSS RefCav transmission is low (TPD is ~2.2 V).  I was unable to improve it much during this last Tuesday maintenance; was hoping that some more stable weather would improve it, as the TPD took a dive late last week and over the weekend as the storm system moved through.  So far the TPD is holding steady at ~2.2V, so an enclosure incursion will likely be necessary to recover back to our usual RefCav transmission levels.

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