= Small meeting on interferometer alignment 2021/03/01 =
Participants: Masayuki Nakano, Yoichi Aso, Yuta Michimura

Zoom meeting: https://zoom.us/j/5045179604

== Minutes ==
 * Start with summarizing the current situation
  * There are some documents by Uchiyama-san such as https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=11544
  * '''A/I:''' Make a hand-writing note [Nakano]
   * Done -> https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=12594
   * In SAL (semi-auto alignment), beam centering are done by eyes (Tcam).
   * Good PRMI alignment and good Yarm alignment might not be compatible. Initially, Yarm alignment was done after Xarm alignment, and then proceeded to PRMI alignment. But somehow, MICH was not in good alignment (AS fringe was dirty). So, SAL procedure was changed to Xarm -> PRMI -> Yarm.
   * [NOTE ADDED ON MARCH 17] IMMT1 was not used for alignment since oplev values were not reliable due to ambient light. 
  * '''A/I:''' Make some slides based on the note [Michimura]
 * Simulation necessary on initial alignment scheme?
  * Maybe not since SAL uses simple cavity configurations for the alignment
  * Might be necessary if we have to balance between beam centering and maximization of intra-cavity power
 * Dithering necessary for steering mirrors at the back of PR2 and SR2?
 * Simulation necessary to simulate controls using WFS, dithering (BPC), and oplev signals.
  * Denationalization of PRC/SRC alignment?
  * Anyone available for the simulation?

 * Other notes:
  * '''A/I:''' Share commissioning paper with Michimura [Nakano]
  * '''A/I:''' Fix steering mirror at the back of PR2 in https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=12593 [Nakano]
  * '''A/I:''' Calculate Xarm and Yarm round-trip loss using POS s-pol and p-pol in past data [Nakano] 
  * '''A/I:''' Summarize the current situation of optical tables [Michimura->Akutsu, Kenta?]

 * Info from Kokeyama-san
  * IFO ASC summary https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=11687
  * IMC ASC
   * http://klog.icrr.u-tokyo.ac.jp/osl/?r=13824
   * http://klog.icrr.u-tokyo.ac.jp/osl/?r=13916