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 * bKAGRA Phase 1 analog electronics [Michimura]
  * MIF agreed on recent electronics request to AEL

ISC Meeting on 2016/8/22 14:00 - 15:00

Participants: Michimura, Aso, Enomoto, Arai, Kambara, Moriwaki, Akutsu, Hirose, (Kawamura)

Next meeting

2016/9/5 14:00 - 15:00

back to Meetings page


  • bKAGRA Phase 1 TMS/mode measurement [Enomoto]
    • by measuring the beam radius at ETM, g-factor can be measured within precision of ~0.09; not enough
    • more precise measurement can be done using transfer function measurement with injected sidebands trough IMC (see LIGO-G080467)

      • consider using this technique
    • it takes only few minutes to adjust PR2-3 length (even in vacuum) [Aso] -> confirm with Shoda again [Michimura]

  • bKAGRA Phase 1 analog electronics [Michimura]
    • MIF agreed on recent electronics request to AEL
  • Output Optics Table [Michimura]
    • MIF group agreed to move this task from IOO to MIF
      • needs agreement from IOO group and then from SEO
    • safety issue on 2 W beam exposure in air should be discussed
  • RF generation scheme [Michimura]
    • IMC sideband frequency (JGW-T1605493)

      • MIF agreed to use f2/8*2.45 = 13.78 MHz for IMC sideband
      • needs agreement from IOO group also
    • may be IMC sideband (and ALS sidebands) should also needs to be phase locked with f1/f2/f3 to avoid "whistling noise"
      • it could be easily done with N5181A, but maybe not with VCXO(OCXO?) to be used in the future
  • NoiseBudget for green lock [Kambara]

    • fiber noise was added (see LIGO-T0900376)

    • Prometheus laser noise was updated to use spec from Coherent
      • real SHG noise is not available yet -> ask Kawabe/Izumi [Kambara]

  • Updates from MIR group [Hirose]
    • availability on reference spheres for PR mirrors will be checked this week at Caltech
    • AR aperture is 204 mm dia for sapphire mirror
      • this size is tolerable considering 35.3 mm beam radius on ITM/ETM and 2.7 sigma (1 ppm loss)
      • aperture of recoil mass should also be checked [Michiura->Tomaru]


  • bKAGRA Phase 1 optical configuration study [Michimura]
    • HOM structure / ASC check [Enomoto] (JGW-T1605362)

      • decided to move PR2/3 by 1.20 cm -> confirm with Shoda again [Michimura]

        • Shoda said 1.20 cm is OK
        • Now the question is how long does it take to adjust it again -> asking Shoda

      • even if we move by 1.20 cm, PRMI is still unstable in worst RoC error case
      • effect on WFS from RF HOMs should be [who?]
      • feedback topology and noise study should be done [Enomoto?]
      • how to measure the g-factor? PRMI cavity scan possible?
      • need to make beam profiling plan [Enomoto]
    • 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

    • beam profiling plan should be compatible with vacuum plan; MIF will lead the planning
      • not only PR2-PR3 but also IMMT1-IMMT2
    • 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? -> look for them on Aug 24 [Nakano]

      • ordered 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?]

      • one by one by hand is tough; outsource?
    • Requested to AEL; meeting with Miyakawa on Aug 24 [Michimura]
  • Output optical tables [Michimura] (OutputTables wiki)

    • Kawamura suggested to move this task from IOO to MIF

    • Is it acceptable?
  • 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? (JGW-T1605493)

  • Arm Length Stabilization plan (JGW-T1605353)

    • NoiseBudget [Kambara]

      • results agreed with Tatsumi Simulink model
      • include fiber noise (fiber setup is different from Tatsumi model)
      • include phase noise from mirror vibration for IR beat setup (it is one of the limiting noise source for aLIGO)
      • schedule and plan for the procurement of circuits should be fixed soon
        • keep in touch with AEL group

  • 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]
    • need to announce to IOO,ISC mailing list; e-mailed to Doi-san for go sign
  • Mirror absorption measurement status [Hirose]
  • Output optics status [Somiya]
    • suspensions for OMMT1/2 is same as IMMT1/2 (driver list for now: JGW-L1605334)

    • 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]

KAGRA/subgroup/ifo/MIF/Minutes20160822 (last edited 2016-08-22 16:55:11 by YutaMichimura)