sheila.dwyer@LIGO.ORG - posted 12:01, Thursday 25 May 2017 - last comment - 13:32, Thursday 25 May 2017(36424)
recycling gain too low for carm offset reduction
Jenne, Sheila, Ed
We think that the problems we are having in the later steps of the CARM offset reduction are caused by a bad alignment and low recycling gain which causes the CARM offset to be incorrect as the guardian goes through the reduction sequence. (Similar to situation descripbed in alog 29082).
We have a few reasons to suspect that the beam has shifted in the PSL, (36412 36408) and after lunch plan to enter the PSL to align onto the reference irisises, and to bring the IM4 spot back to its pre-vent postiion (P=-0.38, Y=-.27) -0.27
The IM4 trans QPD spot position was -0.38 pitch, and +0.27 yaw. The -0.27 was a mis-type in the previous alog.