This morning Peter wanted to measure the NPRO noise when both FSS and ISS were unlocked but he ran out of time to give IFO to commissioners, so all his measurements from the morning was FSS locked. We agreed that we need to disable FSS and measure PMC mixer instead of FSS FAST.
Later I and Sheila quickly disabled FSS and ISS and measured PSL-PWR_NPRO as well as PMC mixer. (When FSS is locked PMC mixer doesn't show anything, as expected.)
In the attached, red and blue are when FSS and IFF were off, green and brown are when FSS was off but ISS was on. (Don't pay much attention to the difference between red and green or between blue and brown, the oscillation was slowly getting smaller as we measure.)
Important message here is that the noise is there both in frequency and in amplitude without ISS nor FSS.
[Jenne, using CoreyA's workstation]
Just out of curiosity, I looked at the equivalent channels at LLO since I'm here. They don't see this noise symptom. In both panels, red is H1 and blue is L1. Top panel is a few days ago (so I could use NDS2), bottom panel is last August before the 70W amplifier install. The NPRO wasn't changed, so it's certainly curious that we have this new feature. My mistake. We do have a new NPRO.
