Reports until 06:42, Friday 15 December 2017
H1 IOO (IOO)
Link
cheryl.vorvick@LIGO.ORG -
posted 06:42, Friday 15 December 2017
(39774)
IO work 14 Dec 2017
IMC flashing
recovery of IM1 to IM2 beam path was not possible
the reflected beam from IM1 is not centered on two apertures that have historically been centered, and the beam is noticeably miscentered on IM2
moving IM1 within it's cage did not correct the beam path
IM1 recentered (as close as possible to it's alignment at install in 2012) within it's cage did not correct the beam path
verified beams on MC1, MC2, MC3, and MC3 Trans irises
verified MC3 iris placement, measured to be 0.2mm off in Y direction from my images (iris base and ruler)
options for cause:
IM1 placement (explored, doesn't correct)
IM1 changes with the bolt torque were 300urad and less,
alog 38808
beam path is wrong (current evidence shows the irises and beam are aligned as they were when IMC was last flashed)
HAM3 refloated/rebalanced (this is the first time flashing the IMC since HAM3 was refloated/rebalanced)
Hugh's
alog 39453
indicates some change in alignment of HAM3
I looked at the HAM3 ISI CPS changes, Nov. 14th (last flashing before HAM rebalanced) to now and see some changes
for reference, at the beginning of the vent, the beam from the IMC made it through the IMs and IO faraday, with no IM alignment biases