aLIGO LHO Logbook

H1 AOS (ISC, SEI, SUS)

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jason.oberling@LIGO.ORG - posted 08:58, Monday 21 December 2015 - last comment - 14:55, Monday 21 December 2015(24356)

Optical Lever 7 Day Trends

Attached are 7 day pitch, yaw, and sum trends of all active H1 optical levers.

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jason.oberling@LIGO.ORG - 14:55, Monday 21 December 2015 (24364)AOS, ISC, SEI, SUS

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After having some time to analyse these, I conclude the following:

Centering
- Need to keep an eye on SR3 and HAM2 pitch, these are starting to approach their linear limits (~25-30 µrad). Nothing to worry about for now, but will need a re-zeroing in the near future.
- All other active oplevs are good.
Glitching
- Can't really tell glitching from the attached trends, so I use the spectrograms posted to the DetChar summary pages (SUS Oplev overview linked, find individual oplevs under the SUS dropdown menu. HAM oplevs not on DetChar pages, only used for alignment purposes so glitching is not a critical issue for them).
- The highest rate of glitches can be found on BS, SR3, and ITMy:
  - BS: I am still adjusting the power to find the glitch-free zone I set on this new laser in the lab; planning another adjustment tomorrow (see LHO WP5667). This is the highest priority as BS oplev damping is still used during DRMI acquisition.
  - SR3: Glitching first reported by Nutsinee and Jenne here. Not a high priority as this oplev is not used for any damping, but since I will be adjusting the BS tomorrow I will adjust SR3 as well (see above linked WP).
  - ITMy: This oplev is still using an unstablized laser on the old style oplev power supply and no thermal stabilization. At this glitch rate this is my next target for laser replacement (to fulfill ECR E1500224), especially as pitch oplev damping is still used for this optic. I have seen no reports of the glitches causing issues with IFO operation.
- ETMx has the next highest rate of glitching.
  - Low priority as the oplev is not used for any damping.
- ITMx and ETMy show very occaisional glitches.
  - ITMx: Like ITMy, this oplev is still using an unstabilized laser on the old style power supply an no thermal stabilization. Barring other lasers requiring swaps due to glitches (i.e. can't fix with a simple power adjustment) this is my next target for laser replacement after ITMy (to fulfill the above linked ECR).
  - ETMy: As ETMx, low priority as no oplev damping is used here.
- PR3 oplev is showing no issues.