PM1 is looking good. We've been having more struggles with this suspension the past few days but figured everything out.

The issue was that the OSEMs suddenly started moving much more and were saturating the ADC. We started seeing PM1 constantly saturating when it wasn't being damped starting this week, when the other undamped suspensions in chamber were not saturating. It seems like this started on Sunday Feb 22, 2026, 21:48 UTC (13:48 Pacific). This is when the purge air line was fixed and let back into HAM1, and when a second cover was installed on the +Y chamber door (89225). The other suspensions aren't moving anywhere near as much as PM1, but PM1 is also on the edge of the table so that might have contributed. I took spectra of PM1 and RM1 for two timespans: last week when the purge air was 'normal' and no one was in chamber, and this week when the purge air was at the new 'normal' and no one was in chamber (ndscope). You can really see the difference in how much more the OSEMs are moving for both suspensions these last few days, and comparing the two suspensions you can also see that PM1 is always noisier than RM1 (PM1, RM1). Luckily as long as we are damping PM1 it is looking good.

After we figured that out and replaced an OSEM (89285), I took some closeout transfer functions for PM1. They're looking good and comparing them to May 2025 and to a few days ago before the OSEM swap, they match up well

Settings:
- ISI DAMPED
- DAMP OFF
Data:
/ligo/svncommon/SusSVN/sus/trunk/HTTS/H1/PM1/SAGM1/Data/2026-02-26_1730_H1SUSPM1_M1_WhiteNoise_{L,P,Y}_0p02to50Hz.xml
Results:
/ligo/svncommon/SusSVN/sus/trunk/HTTS/H1/PM1/SAGM1/Results/2026-02-26_1730_H1SUSPM1_M1_ALL_TFs.pdf
r12925
Comparison:
/ligo/svncommon/SusSVN/sus/trunk/HTTS/Common/Data/allhttss_2026-02-26_PM1_May2025vsFeb2026_ALL_TFs.pdf
r12928