After the fiber swap mentioned yesterday, it seems that the crazy big noise (blue trace) was gone (red).
From 13:47 to 13:57 local time, I turned the laser room HEPA and A/Cs off, turned down the ante room HEPA to 55%, and make up air to 75%.
During this time the lights were ON, I and Rodica were in the ante room but otherwise things were really quiet.
Also on the plot are various noise levels from the old refcav setup. The difference between red and everything else at 1Hz is the ISI isolation.
Anyway, the red trace is the best we got today. It was glitchy and once in a while we got a big glitch, but otherwise the noise level was much better than blue. Still, the noise level was varying between red and maybe brown.
It's clear that we need a serious debugging if we want to get to the root of this, and it's not a one-day job. It seems to me that we need the corner station anyway to proceed any further, and I don't think it makes sense to block other things (including the HIFO installation) for the one arm test further.
I'll likely declare that we're done with dedicated one arm test in the morning. That doesn't mean that people cannot do one arm measurements when the arm is still available in the evenings, but we won't block installation activities during the day time.
From about 16:00 to 18:00, I turned off the laser room HEPA, turned down ante room HEPA to 55% and the make up air to 75% while leaving A/Cs on. Lights were off.
During this time, Vincent was doing his SEI measurements, but the cavity was locked for some part of this, so you can look at the length data if you want.
Later Vincent will post the details of the SEI configuration, i.e. the starting GPS time of each of the configurations, so you can tell which time to look for which configuration.