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Reports until 00:41, Wednesday 29 June 2016
H1 ISC (CDS, PSL)
sheila.dwyer@LIGO.ORG - posted 00:41, Wednesday 29 June 2016 - last comment - 19:41, Wednesday 29 June 2016(28045)
trying to improve recycling gain

Marie, Sheila, Kiwamu, Lisa, Stefan

We tried a few things to improve the recycling gain tonight. We  believe that the problem is with something in our PRC.  We can see that the green power transmitted through the X arm stays stable as we power up, we think this means the optics are stable.  When we move the soft offsets to improve the recycling gain we change the X arm alignment to follow something in the vertex.

As TJ noted, since the computer problems earlier we are having trouble relocking the PSL after locklosses, with noise eater, PMC and FSS and ISS problems.  It seems like trying to lock the FSS causes the noise eater to oscillate again after it has been reset. 

Comments related to this report
kiwamu.izumi@LIGO.ORG - 12:12, Wednesday 29 June 2016 (28058)

Jeff K, Stefan, Peter, Kiwamu

We kept having the same issues with the PSL in this morning as reported by Sheila in the above entry. We now think that it is all fixed. Here are what we have done for fixing the issues.

  • At the begining, no issues were found and in fact Jeff was able to lock at 40 W. Then the lock was broken due to the angular instability and we started having the issues.
  • First of all, we noticed the noise eator oscillating. Peter went to the floor and fixed it.
  • Having trouble engaging the FSS, we noticed that the FSS common gain was too high by 6 dB. We set the common gain back to 14.
    • The Observe snapshot said it should be 20.4 dB, but the safe snapshot said it should be 14. We set the observe to 14 dB.
    • The gain seemed to have been set to 20.4 dB after the maintenance yesterday.
  • Then having trouble engaging the ISS, we noticed that the PMC gain was too high by 6 dB too. We set this back to 16 dB.
    • This also seemed to have been set to 22 dB after the maintenance yesterday.
    • After this reset, the ISS seems to work well.
jeffrey.kissel@LIGO.ORG - 19:41, Wednesday 29 June 2016 (28071)
Not that all of the settings that Kiwamu describes were not found by the SDF system because I'd mistakenly set the SDF system to look at the OBSERVE.snap record instead of the SAFE.snap record after maintenance yesterday. The OBSERVE.snap was out of date, having not been updated since O1 and/or the HPO turn-on. Both the safe and OBSERVE.snaps have not been updated. 

Another case of the difficulty of maintaining several .snap files per front-end model...
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