ISC Meeting on 2016/8/8 14:00 - 15:00

eZuce:

Participants:

Agenda

• bKAGRA Phase 1 optical configuration study [Michimura]

  • HOM structure / ASC check [Enomoto] (JGW-T1605362)

    • we found mistake in the HOM structure check code
      • PR2-PR3 length re-calculation ongoing

      • check if we can move xxx cm [Shoda->ATC]

    • Comments
      • Feedback topology. Change which mirror to feedback depending on the frequency?
      • Using DC signals for TMs may not be good from the view point of noise.
      • How to measure the precise distance between PR2-PR3?
      • How to de-couple the distance error and ROC errors?
  • check if reference spheres for PR mirrors are available at Caltech [Hirose]
  • check if IMC length stability and others are compatible with 3-km PRMI [Michimura]

• bKAGRA Phase 1 initial alignment / commissioning plan [Michimura]: JGW-T1605274

  • discussed at Extended Chief Meeting on July 4 (JGW-G1605352)

    • beam profiling plan should be compatible with vacuum plan; MIF will lead the planning
    • how to extract AS beam should be fixed by MIF
    • CRYp agreed on installing ETMY earlier by two months (ETMY CRYp: 2017.8-9, ETMX CRYp: 2017.12-2018.1)
      • use 2017.10-11 to test PR-ETMY and ETMY cooling

        • negotiate with CRYp to fix ETMY cooling schedule

• bKAGRA Phase 1 analog electronics (Analog Electronics for ISC) [Michimura]

  • Quad IQ Demodulator heat-up issue
    • 1st stage amp is heating up

    • we have to decide if we need 1st stage amp or not

  • remake of Quad IQ Demodulator LSC to ASC [Michimura->Niigata students?; by 2016.10]

    • MIF will take care istead of AEL
    • mass production will be taken care by AEL

    • 4-way splitter (Mini-Circuits ZFSC-4-1-S+) arrived at Kamioka -> Mozumi office loft

  • RF Distribution Amplifier [Michimura->Niigata students?; by 2016.10]

    • we will omit RF monitor for now, and add them later

    • where did front/rear panels go?

    • in the process of ordering RF amp (Wenzel LNBA-11-23-CK-100-15)

    • 8-way splitter (Mini-Circuits ZCSC-8-1+), coupler (Mini-Circuits ZX30-20-4) arrived at Kamioka -> Mozumi office loft

    • basically copy of LIGO-D1000124, but we will omit Interface for the first stage

    • ask LIGO people for necessity of RF monitor [Michimura]
      • RF monitor was used in aLIGO for noise hunting and IFO health check (input from Izumi)

    • we have to request AEL to make interface board

  • RF Patch Panel modification [Michimura->Niigata students?]

• RF generation scheme [Michimura]
  • f1 = 3/8*f2, f3 = 10/8*f2
  • we need 2*f1, 2*f2, f3-f1, f3-f2 as well
  • use harmonics generator (x2, x3, x6, x8, x10, x16 for f2/8 = 5.62698725 MHz (FSR for IMC))
    • seeking for vendors

  • sideband frequency for IMC? (should be determined before EOM production; by the end of 2016.8)

    • f2/8*2.45 = 13.78 MHz for IMC anti-resonance?

• Arm Length Stabilization plan (JGW-T1605353)

  • ALS Meeting on July 27 (Minutes page)

• bKAGRA optical layout around PRC
  • POY clipping issue will be solved by modifying PR3 optical bench suspension [Shoda]
  • we need layout CAD for POY pickoff mirror, POP pickoff mirror to design baffles

    • possibility of buying baffles next FY? -> ask SEO [Aso]

    • ask SEO to hire a person dedicated for optical CAD
    • layout CAD will be prepared by each subgroup for the time being
• iKAGRA post-run calibration mystery [Aso]
  • mysterious LPF was from saturation

  • write an elog about this conclusion [Aso]

• Requirement for the noise of watchdogs for coil drivers [Aso]

  • recent result show dR < 1e-7 Ohm/rtHz, so it may meet the requirement

  • slow (~20 min) drift at dR ~ 5e-4 Ohm -> this should be negligible

• Viewport quality for GV between SRM and OMMT [Akutsu]
  • aLIGO case: SRM-OFI-viewport, KAGRA case: SRM-viewport-OMMT-OFI
  • aLIGO viewport is always closed

  • if we need super quality viewport, we have to decide soon

• BS baffle could make contract defect? (LIGO-T1000090)

  • ask Akutsu and Hiro
  • BS has 370 mm dia and beam at BS is 2*36 mm dia. So, it should be in principle OK. But recoil mass aperture should be considered.
• bKAGRA ISC cabling [Michimura/Doi]
  • Doi-san said he will help.
• Mirror absorption measurement status [Hirose]
• Output optics status [Somiya]

  • suspensions for OMMT1/2 is same as IMMT1/2, ask Takahashi-san to add drivers to his list: JGW-L1605193

  • we have to make vacuum compatible PD/QPD for OMC by 2018.3
  • beam shutter: prototype done, AR coating and driver circuit design not yet

  • OMC suspension requirement cross check [Somiya]

• Magnetic noise, actuator noise calculation for cryogenic payload [Michimura]

  • Ask Tomaru about the parameters and actuator design, range

• Task list update (TaskList) [Michimura]

Next meeting

2016/8/8 14:00 - 15:00

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