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Reports until 13:06, Thursday 11 June 2026
H1 PSL
ryan.short@LIGO.ORG - posted 13:06, Thursday 11 June 2026 (90594)
PSL PMC and RefCav Remote Alignment Tweak

I finally got around to doing some slight alignment tweaks this morning following the power outage and PSL recovery a bit over a week ago.

I started with the remotely-controlled picomotors upstream of the PMC to touch up its input alignment with the ISS off:

Some improvement here, but I couldn't quite get the transmitted power back up to the >104 W level it was before the outage. Perhaps amplifier pump diode currents need to be adjusted, or some more invasive alignment tweaks are needed. I then turned the ISS on and adjusted the RefSignal to bring the diffracted power percentage back up to 4% from around 3%, and proceeded with RefCav adjustments:

Again, good improvements, but the highest I've seen this signal get in recent memory is around 550 mV, so the FSS path may need a full tune-up sometime. Not completely surprising, as it's been a while since the last one.

Attaching a screenshot of the quad display after my adjustments for posterity.

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