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  * [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=11889]]   * [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=11889|Presentation slides]]

Agenda/Minutes of the VIS Meeting on 2020/8/19

2020/8/19 14:00 -

Zoom Meeting


Progress report



  • Started procurements of LVDT coils for ACCs.
  • [Miyo] Investigate the broken? coil of ETMY_IM_V3. klog14914


  • Terrence offloaded SR3 F0 actuation using the fishing rod (klog 14890).

  • As advertised in the VIS meeting on the 6th of March 2020 there's a document describing the remedying for Type- suspensions: JGW-E2011534. It's still a bit messy but it's been updated with procedures.

  • BS IP position and outer frame beams: During the review of the Type-B remedying work I began thinking about the effects of the installation of the BS outer frame beams: installation will likely change the position of the upper platform which supports the IP, thus changing the position of the IP also. I've asked Uchiyama-san if we could measure the frame upper platform displacement using dial gauges. If so we could compensate by setting a new appropriate set point for the IP.

  • Oplev box and outer frame beams: I asked Akutsu-san about the oplev box status: Mirapro is not designing anything yet. Very likely we will need to completely remove the oplev optics to install the box. The installation of the BS outer frame beams will likely require removal of the oplev receiver optics.

  • Question for Satou-san: Have we bought the cables requested for the yaw stepper motor for Type-B suspensions? They were requested on 06/03/2020 meeting where the specifications were also given.

  • Question for Takahashi-san: the geophones we used in the TAMA Type-B prototype, are we using them anywhere in KAGRA? I'm asking because the geophone noise in the prototype seemed to be smaller than the one we observe in KAGRA.

  • Question for Tanaka-san: do the stepper motor have a unique polarity? As far as I understand they do have a unique polarity. I tried to change it twice but the driver channel broke.





Towards O4

  • KAGRA is in "Upgrade phase for O4".
  • Procedure documents.
    • Type-A tower

    • Limit switches

      • Question from Fabian: I took a cursory look to the procedure and I didn't find information on how the swtiches are attached to cables or wires. Are they crimped, does crimping provide suitable mechanical support or cable clamps are needed, what wire thickness should we use in order to have appropriate mechanical support?

    • Replacement of TF blades (Draft)

    • Wire gluing in PR3 (by Shoda)
    • Type-B remedying work:
      • Description and procedures can be found in JGW-E2011534.

      • Fishing rods remedying: a summary of the situation is described in this presentation.

  • Schedule towards O4 was revised (Chart).

cf. Post Obs. task (Request), Task for O3c (Plan, Sheet), Task towards O4 (List)



  • [Terrence] New features for the suspensions, type-A and type-B, as pre-O4 upgrades.

Travel Plans

Next meeting

  • On 2020/8/28(Fri)

KAGRA/Subgroups/VIS/VISMinutes20200819 (last edited 2020-08-19 16:08:54 by RyutaroTakahashi)