LOG-IN
Displaying report 1-1 of 1.
IOO (IMC)
Print this report.
masayuki.nakano - 00:44, Wednesday 07 November 2018 (6874)Get code to link to this report
Comment to Lock-loss investigation of the IMC (Click here to view original report: 6856)

[Yutaro, Masayuki]

We found that the IMC and RefCav lock-loss happens every 1 hour with the error of a couple of minutes. Fig. 1 plot shows the IMC-TRANS (REFL) and the REFCAV-TRANS (REFL) for the 1 day-long.

The reason why we did not realize that the lock-loss events are periodic is that each event is very short. Therefore, we cannot see several events on the striptool or the Epics channel, and the guardian cannot realize those events. Fig.2  is the 1-sec plot of the test points with the full data.

We could not come up with the idea what cause these periodic events. So, if anyone has the idea, please let me know.


Fig.1 1-day trend of the TRANS and the REFL signals

 

Fig.2 Lock-loss event.

 

Buy the way,

I found that the TFP on the IMC REFL table was not fixed well. Also, the mirror mount for the TFP was not installed in the proper direction. The transmitted light is close to crip at the mount. I fix it, and I expected that is the reason for the lock-loss.

Images attached to this comment
6874_20181106163457_screenshotfrom20181106234148.png 6874_20181106163857_screenshotfrom20181107003637.png