cheryl.vorvick@LIGO.ORG - posted 23:59, Tuesday 12 December 2017 (39742)
IO work 12 Dec 2017
- the IMC is flashing and the beam is through the IO Faraday
- I had to align from the PSL twice today, due to finding the beam on the MC1 iris was off in yaw about half way through the day (plot attached)
- HAM2 tool stock has dwindled, so it took a while find a short allen key that I could use on the bottom left IM3 OSEM (clearance issues with MC3)
- there was significant fringing at times during the day, that made alignment a challenge, and this appears to be due to ground/beam tube motion
- IM3 needs a major realignment, and while this is going well, I am still working on getting the beam aligned to where it needs to be, and at the same time, getting all of the OSEMs centered enough that I can damp the optic
- I adjusted, for the first time, the pitch of IM3, and found that I could easily turn the bolt under the optic that controls the pitch
- I should not have been able to easily adjust that bolt, since that bolt has a collar that is supposed to be tightened to secure the bolt in place
- my finding today suggests that that bolt has not been secured with the collar for a while, so likely it's been loose since before O1
- chalk this up to another way the alignment of IM3 could have changed while the chamber is under vacuum, for example, during an ISI trip (shaking)
- I'll attempt to tighten the collar tomorrow without taking the baffle/Viton off of the front of the IM3 cage, but if I can't, I'll have to take the baffle and Viton off to access the locking collar
Images attached to this report
