Reports until 14:13, Thursday 04 December 2014
H1 ISC
keita.kawabe@LIGO.ORG - posted 14:13, Thursday 04 December 2014 - last comment - 16:01, Thursday 11 December 2014(15446)
4 DOF green WFS works, at first for X arm

As proposed, WFSA (hard sensor) is fed back to the ITMX and WFSB (soft sensor) to the TMSX.

In the attached, you can see that even when I made a terrible kick such that the transmission dropped below 50%, it eventually came back on its own.

Short lock losses don't kick the WFS out of range, and as of now it is maintaining green transmission between 1.15 and 1.18 for 30 min.

ITMX beam position control (fed back to ETMX) is not implemented yet, but should be easier than WFSs themselves.

Eventually we might be able to change the scheme such that hard is fed back to hard, soft to soft, and then ITM beam position to TMS, but I'm doing it this way as it is easier.

Before doing camera, however, I'll move to Y arm.

Images attached to this report
Comments related to this report
sheila.dwyer@LIGO.ORG - 16:01, Thursday 11 December 2014 (15564)

The X arm green WFS are running again this afternoon, and they did bring the cavity to a high build up.  I reduced the gain from 0.5 to 0.25 because it oscillated when I first turned it on.  I've edited the guardian to turn this on and off.