• KAGRA
• subgroup
• ifo
• MIF
• Minutes20250530

In-vac PD/QPD layout meeting 2025/05/30

Time: May 30, 2025 14:00-14:40

Participants: Huali Chen, Ryan Yang, Yoichi Aso, Yuta Michimura

Zoom meeting

Minutes

• REFL (Ryan)
  • In-air layout basically complete.
  • Need to update the following:
    • Remove in-vac periscope and add in-air periscope
    • Make in-air path parallel to the grid of M6 screw holes of the optical table
  • Current periscope changes the height by 92.4 mm to make the in-air beam height to be 4 inch
  • Need to start designing the vacuum tank
• AS (Ryan)
  • Included new optical layout in the CAD drawing.
  • 0.5 inch optics and 2 inch lens need to be modified to 1 inch. Use 1 inch for all.
  • Basically OK, but ORM6 interferes with a foot of OMC shroud. Need to be discussed with relevant people.
    • Slightly modify OMC REFL pick-off mirror angle, or modify OMC shroud or modify ORM6 pedestal
  • Periscope for in-vac layout in OMC tank needs to be designed.

    • Height change 210 mm -> 1 inch

  • Periscopes, beam diverters, RF QPDs, optical bench need to be designed.
• POP (Yuta)
  • Need to collect information for start designing things.

• A/I

  • Update REFL and OMC layout based on the comments today and upload the current version to JGWdoc [Ryan]
    • DONE

    • 20250530_RFQPD and RFPD Optical Layout of REFL Port_2D https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=16702

    • 20250530_OMC chamber 3D drawing https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=16705

    • Found new issue that height of ORM1 is not consistent
  • Consult with relevant people on how to deal with ORM6 and OMC shroud situation [Yuta]

    • Beam layout in the CAD drawing Sato-san provided is based on the design, but the position of the optics are based on the actual locations as installed. https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=16678

    • So, ORM6 situation should be fine.
    • As for the height of ORM1, this is due to the base of OFI. Just need to adjust the height of the pedestal.
    • Also ,ORM1 also need to be 1-inch optic (currently, it is 0.5-inch in the drawing).
  • Consult with VAC people to start designing REFL PD tank [Yuta]
  • Collect some information to start in-vac periscope design [Yuta]

    • ALIGO IO L1 IN VACUUM INPUT PERISCOPE ASSEMBLY https://dcc.ligo.org/LIGO-D1002350

    • ISC TransMon Periscope Lens Bracket https://dcc.ligo.org/LIGO-D1003296/public

  • Collect some information to start POP design [Yuta]

    • See last two pages: https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=16178

• Next meeting: TBD on the week of June 23 ?