Jennie W, Sheila D
I compared our optical gain and power-recycling gain between this afternoon once we were thermalised at 22:42:59 UTC and a thermalised time just before the vent on April 1st at 07:34:01 UTC.
Our optical gain looks like it has decreased by around 1% and our PRG from 52 to 50 W/W.
This might make it worth tweaking our OMC alignment to improve optical gain, but the the PRG hasn't changed much so its maybe not worth trying to improve this before the run starts by tweaking camera servo offsets.
We should be careful with the PRG comparison- I am not sure the change in the PRG is "real" because before the vent, we had not updated the PRG calibration to account for reduced power on IM4 trans that occurred after the O4a/O4b break. However, I did update the PRG calibration last week to account for it. It could still be correct; one reason why I didn't update the PRG calibration before was because it seemed "good enough", but I'm not sure if it's good enough to a few percent to make this kind of comparison.