betsy.weaver@LIGO.ORG - posted 21:55, Tuesday 15 May 2012 - last comment - 13:11, Wednesday 16 May 2012(2870)
BSC8 Chamber Closeout
(Betsy, Travis) After Richard/Filiberto fixed the broken ITMy L2 OSEM signal (swapping a board), and we confirmed that actuation was evident on the appropriate channels, we went in and finished the last items in BSC8: - Set M0 and R0 Left and Right Top Stage BOSEMs, and M0 PUM and EMTy barrel EQ stops, to account for buoyancy. - Took photos. - Removed all tools, stools and did once-over on chamber "cubbies" looking for hidden treasures. - N2 blowoff of optics (still see surface particulate on surfaces of the 10-20 particles/sq. in. level. Blowing did little to reduce this number. Hmmph. (Note, the FC had been removed early last week and the optic surfaces have been exposed since while unexpected diagnostics took place the last few days.) -Set witness plates. We're hoping Garcia can collect a final L2 TF set in the morning, but we see no reason not to shut the door to this chamber.
The "making sure actuation was on the appropriate channels" was not completely confirmed - a quick DTT test in the control room merely showed we could create a sine wave on a channel and readout a signal from the auxiliary ("_*VOLTMON_*") channels. The attached plot shows we can drive in one OSEM but see better coherence in another OSEM (but not completely coherent). This does not confirm that we are driving the pins that correspond to the MEDM channel names. The MEDMs may be correct in driving the correct pin outs, but the response signal could possibly be crossed. To summarize: Yes, there is the ability drive channels and see a response, but whether that corresponds to reality (the wiring diagram D1001725) is not completely confirmed as of today.