ISC Meeting on 2016/9/5 14:00 - 15:00

Participants: Michimura, Enomoto, Arai, Aso, Haino, Miyakawa

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Minutes

• bKAGRA Phase 1 optical configuration study [Michimura]

  • ASC sensing matrix for (JGW-T1605362) was updated to reflect PR2-PR3 length decision [Enomoto]

  • summary of Phase 1 study [Michimura] (JGW-T1605595)

    • MIF agreed with this goal
• Output optical tables [Michimura]
  • need to check noise performance and transimpedance RF PDs and RF QPDs
    • RF PDs could have higher noise (~5 mA?) than aLIGO ones (~2 mA?) because of the modification done
  • we also have to modify RF PD to
    • fix DC path
    • solve single supply issue (RF PDs easily break when accidentally supplied with single)
    • fix plugs so that Dsub 9pin cable fixes better
• RF generation scheme [Michimura]

  • ALS sideband frequencies JGW-T1605626

    • MIF agreed with 32 MHz for ALSX, 33 MHz for ALSY plan
• Aperture of sapphire test mass
  • Recoil mass aperture is 191 mm at min for HR side, 188 mm at min for AR(coil) side
    • requiring diffraction loss of 10 ppm, 2.4 sigma aperture is needed
    • considering 35.3 mm beam radius on ITM/ETM, 188 mm is tolerable for diffraction loss
    • from order estimate, scattering noise should also be OK

      • <10 ppm scattering from recoil mass is roughly same as few ppm scattering from mirror surface

  • what is the baffle aperture?
• bKAGRA optical layout around PRC
  • POY clipping issue will be solved by modifying PR3 optical bench suspension [Shoda]
  • budget for baffles around POY and POP were shifted to next FY [SEO]
    • so we don't need precise layout CAD around POY and POP for now

Agenda

• bKAGRA Phase 1 optical configuration study [Michimura]

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

    • decided to move PR2/3 by 1.20 cm
      • this is possible even in vacuum [Shoda confirmed]
      • adjustment takes only few minutes

    • precise TMS measurement can be done using transfer function measurement with injected sidebands trough IMC (see LIGO-G080467)

      • consider using this technique
      • cryopayload installation finish on Feb 2, 2018 and cool down start on Feb 19
      • could be tough to do TMS tuning considering schedule
    • effect on WFS from RF HOMs should be simulated [who?]
    • feedback topology and noise study should be done [who?]
  • check if reference spheres for PR mirrors are available at Caltech [Hirose]
    • 9.0m (CC), 11.5m (CC), 6.5m (CC), 5.0m (CC), 34m (CX), 36m (CX) were available
    • PR2/SR2 is -3.0764m/-2.9872m and PR3/SR3 is 24.9165m. Maybe 5.0m TS can be used for PR2/SR2.
    • what about PR3/SR3, PRM/SRM?
  • check if IMC length stability and others are compatible with 3-km PRMI [Michimura]

  • summary of Phase 1 study [Michimura] (JGW-T1605595)

• 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
  • according to CRYp current schedule;
    • Nov 1, 2017: ETMY CRYp installation done
    • Nov 21, 2017: ETMY cool down starts
    • Feb 2, 2018: ETMX CRYp installation done
    • Feb 19, 2018: ETMY cool down starts
  • we need more time for PR-ETMY cavity

    • negotiate with CRYp to fix ETMY cooling schedule

  • initial alignment plan including green is taken cared by MIF [confirmed with Kawamura, Moriwaki on Aug 30]

• 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

    • Nakano found front/rear panels -> Mozumi office loft

    • 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

    • ordered cables and connectors to assemble one chassis by hand [Kokeyama,Michimura]

    • 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)
    • asked AEL to make RF amplifier interface board (which is also used for Frequency Doubler) [Michimura]

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

    • one by one by hand is tough; outsource?
  • Electronics request meeting with Miyakawa/Kamiizumi on Aug 24
    • 4 chasses of Quad IQ Demodulator ASC by July 2017 might be tough, but all the others are OK
    • Quad IQ Demodulator ASC is not so high priority anyway (compared with coil drivers for VIS)
    • Rear panels of RF Distribution Amplifier will be updated for RF monitor
    • we might have to help them with ordering RF components
    • photos of the assembled chassis are helpful for AEL

      • does anyone have a photo of Frequeny Doubler? LIGO-D1002178

• Output optical tables [Michimura] (OutputTables wiki)

  • Kawamura suggested to move this task from IOO to MIF

  • vacuum optics to extract beams for each port (except for REFL and AS DC) and related beam shutters will also be MIF task
  • MIF and IOO agreed, waiting for SEO to agree
• 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

  • MIF and IOO agreed to use 13.78 MHz　(~= f2/8*2.45) for IMC sideband (JGW-T1605493)

    • sent email to Uehara; he is already tuning the resonance close to this value
  • may be IMC sideband (and ALS sidebands) should also needs to be phase locked with f1/f2/f3 to avoid "whistling noise"

  • how to decide ALS sideband frequencies? JGW-T1605626

• 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

• Aperture of sapphire test mass
  • 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)
  • Recoil mass aperture is 191 mm at min for HR side, 188 mm at min for AR(coil) side
    • is this OK?
    • what is the requirement for the recoil mass miscentering with respect to test mass center?
• 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]