KAGRA Logbook

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AOS (Baffles & Beam dumps)

kouseki.miyo - 13:11 Friday 09 February 2018 (4152)

Some angle shifting during our work

Simon, Miyo

Today"s work was to estimate pitch, yaw, roll of tilting using laser leveler. I think Simon report later.

Although I shook WAB large touching my finger while we measure angle, fortunately, there are no big differences in pitch and yaw.
PIT change at most 300 rad, which is equal to 0.02 degree. This tilting is less than 1degree required by WAB design simon told me. On the other hand, YAW is much less.
Good. Yokatta-yokatta.

Anyway, linear range is about +/- 200 according to klog:4147, so beam should be centered or expand beam radius.
I think beam radius should be wider.

Images attached to this report

Comments to this report:

simon.zeidler - 15:55 Friday 09 February 2018 (4156)

Basically, it wouldn't be a big problem to set a lens in front of the QPD to widen the beam. However, we then have to set the QPD-stage a little bit further away from the viewport to get more space.

Another option would be to use a different collimator which has a shorter collimating range.