[Kokeyama, Ushiba]
Since transmitted light power of PRFPMI is much larger than that of FPMI, TMSX QPD and camera is satulated.
So, we reduce the laser power at the QPD and camera by putting 98% reflection beam splitter in front of them.
Detailed beam path will be posted by Kokeyama-san with some pictures.
Now, sum out of QPD is below 100 with X-arm locking without power recycling.
So, it will not be satulated when PRFPMI is locked.
The attached pic+drawing shows the modified TMSX layout.
It is also posted as https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=11437 linked from the in-air detection top page.
By the way, we noticed that the bottom part of the TMSX IR beam is very slightly clipped :( We tried to identify where, and the clipping seemed to happen in the in-vac part.
Sorry so much. Hmm...
Does it become apparant thanks to PRFPMI??
Anyway I'd like to try whether slight moves of the TMS-VIS (from MEDM) would help such clipping or not.
According to Nakano-kun, the clipping has been known for long time. It was seen only when the power is enough low and the image was not saturated.
