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Time: Nov 20, 2024 10:00-10:30 Time: Jan 23, 2025 14:00-15:00
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   * We can also mount disc+piezo+mirror on a picomotor mirror mount to realize both actuation with one steering mirror
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  * Check if OMC REFL in-air is necessary [Michimura]   * Check if OMC REFL RF QPD in-air is necessary [Michimura]
   * May be not. Beacon WFS is used only after locking OMC (before handing over to DC readout). LIGO is also not using OMC REFL in-air (they only have in-vac OMC REFL DC QPDs; [[https://dcc.ligo.org/LIGO-T1000264/public|LIGO-T1000264]])

In-vac PD/QPD layout meeting 2025/01/23

Time: Jan 23, 2025 14:00-15:00

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

Zoom meeting

Minutes

  • Huali showed the layout idea for AS RF and OMC REFL, with squeezing injection optics.
    • Add periscope to reduce the height approx. 210 mm -> 4 inch) and use smaller pedestals (footprint for 210-mm-high mirror is dia. 78 mm; see JGW-D1503916).

    • Add existing AS RF in-air and OMC REFL in-air paths in the layout and see if all of them can co-exist.
    • Try to simplify the layout by removing some of the steering mirrors to avoid scattered light from steering mirrors as much as possible.
    • We can also add some extension plate to extend the table
    • Do we really need two steering mirrors (one for piezo and one for picomotor) before each QPD?
      • We can also mount disc+piezo+mirror on a picomotor mirror mount to realize both actuation with one steering mirror
  • A/I

    • Check if OMC REFL RF QPD in-air is necessary [Michimura]
      • May be not. Beacon WFS is used only after locking OMC (before handing over to DC readout). LIGO is also not using OMC REFL in-air (they only have in-vac OMC REFL DC QPDs; LIGO-T1000264)

    • Check what LIGO is doing for RF QPD centering (only picomotors?) [Michimura]
      • REFL WFS: Two tip-tilts before WFS sled, two picomotor mirrors on WFS sled LIGO-D1000313

      • AS WFS: Two tip-tilts (OM1, OM2) before WFS sled, two picomotor mirrors on WFS sled LIGO-D1000342 LIGO-T1200410

    • Upload the slides to JGWdoc, and present the current status at the ISC meeting on Jan 27 from 15:00 JST [Huali]
  • Next meeting: TBD

KAGRA/subgroup/ifo/MIF/Minutes20250123 (last edited 2025-02-28 15:18:23 by YutaMichimura)