= In-vac PD/QPD layout meeting 2025/09/12 =
Time: September 12, 2025 14:15-15:15

Participants: Huali Chen, Ryan Yang, Ray-Kuang Lee, Yoichi Aso, Yuta Michimura

Zoom meeting

== Minutes ==
 * POP design (Ryan)
  * Redesigned the layout based on q-parameters qx and qy estimated from the green beam.
  * But need to be double-checked with Aso-san's Main interferometer parameters.

 * OMC chamber (Ryan)
  * Updated to add RF QPD base plates, periscopes (now too big), beam diverter, and fast beam shutter (OFI moved by 40.299 mm in +Y direction).
   * https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=16705

 * In-vac periscope (Ryan)
  * Did the resonant frequency analysis of the first design using Inventor FEM.
   * https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=16873
   * Fixed-height periscope and adjustable-height periscope had similar resonant frequencies, which seems to be strange.
   * It could be due to the complex structure of the periscope (mirror mounts, screws)
   * It would be better first to check the resonant frequencies parts by parts.
  * Due to limited space, let's design a periscope with 2 inch mirrors fixed plates fixed on a rectangular structure.

 * '''A/I'''
  * Consult with VAC people to start designing REFL/POP PD tank [Yuta]
  * Design a new periscope with 2 inch mirrors fixed on plates (not mirror mounts) on a rectangular structure. [Ryan]
   * Check the resonant frequencies with FEM [Ryan]
  * Update POP layout based on q-parameters from Aso-san [Ryan]
   * POP at PR2 AR is qx=-1.1801+0.02671i, qy=-1.1812+0.02674i
   * POP forward at PR2 AR is qx=-6.7646+0.80946i, qy=-6.7780+0.81116i
  * Add in-air green, POP and POP forward layout [Ryan]
  * Create cable list (RF QPDs, picomotors, PZTs, beam shutter, beam diverter) for OMC chamber to see their weight for designing OMC vibration isolation table [Yuta; by the end of September?]

 * Next meeting: TBD