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 * Flat ETM for bKAGRA Phase 1? {*}

ISC Meeting on 2017/1/30 14:00 - 15:00

Participants:

Next meeting

2017/2/13 14:00 - 15:00

back to Meetings page

Agenda

  • Flat ETM for bKAGRA Phase 1? {*}

  • bKAGRA Phase 1 optical configuration study [Michimura]

    • summary: JGW-T1605595

    • ASC [Enomoto]

      • noise study by NoiseBudget [Enomoto]

        • Enomoto volunteered to do ASC NoiseBudget; meeting on Sept 27

          • trouble on number of licenses and library links, but finally able to run example model
      • effect on WFS from RF HOMs [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]

  • bKAGRA Phase 1 initial alignment / commissioning plan [Michimura]: JGW-T1605595

    • procedure summarized in JGW-T1605692 {*}

      • presented at Chief Meeting on Sept 26

      • TMS BRT alignment could be tough because of faint transmitted beam after ETM installation (~0.25uW)

        • use green?
          • BS transmission for green is S:99.40% P:97.85% at 45 deg
          • 100 mW green beam from PR gives ~0.12 mW at ETMY transmission

      • check optical layout [Michimura->Aso]

    • check if ETM transmitted beam can go through when ETM is not installed [Michimura] {*}

      • ETM transmitted beam can reach EXT/EYT when no wedge (5.6 mm shifted from the center of EXT/EYT)
      • EXT/EYT tanks/ducts are installed considering ETM wedge effect

    • wide/narrow angle baffles for Phase 1? [Akutsu] {*}

      • talk with Uchiyama & Saito on Sept 27-28?

        • as for NAB: install if possible, but maybe without suspension
        • as for WAB: try WAB with suspension at EXC, maybe no installaton at EYC
        • first priority is cryopayloads and evacuation/cool-down

    • camera to see ETM HR surface [Akutsu, Inoue, Kokeyama] {*}

      • CAL report (JGW-G1605737)

      • wide angle baffle modification is needed to see the ETM edge
    • how to extract AS beam should be fixed by MIF

      • extract SR2 reflected beam at SR3 chamber (decided at the meeting on Sept 13) {*}

      • Layout around SRs (JGW-T1605967)

    • IMMT1-IMMT2 beam collimation plan not yet [MIF]
    • green alignment plan not yet [MIF]

    • TMS possible without ITM? [Akutsu->Michimura]

      • check q-parameter at TMS witouht ITM

  • 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

    • Quad IQ Demodulator LSC to ASC

      • 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 JGW-D1504460

      • we will omit RF monitor for now, and add them later
      • front/rear panels, RF amps, 8-way splitters, couplers, cables and connectors at Mozumi office loft
    • RF Frequency Doubler

      • what's the frequency? [Kamiizumi->Michimura] {*}

        • thought used for 2*f1,2*f2, but aLIGO uses them for ALS

    • Requested Universal Whitening Filter with DC Power to AEL (JGW-T1605839) {*}

  • RF PDs and RF QPDs
    • RF PD / RF QPD noise and transimpedance characterization
      • we need permanent test bench
    • RF PD modification [who?]
      • 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 Cables

  • Output optical tables [Michimura] (OutputTables wiki)

    • vacuum optics to extract beams for each port (except for REFL and AS DC) and related beam shutters will also be MIF task
    • EXT/EYT tables
      • table height fixed; they will be put on mortar surface
      • isolation floor cutting and mortar application plan sent to Mirapro
      • installation on Mar 2017, along with installation of EXT/EYT chambers?
    • POS and AS tables
      • table height fixed; POS will be on concrete surface, AS will be on mortar surface

  • Arm Length Stabilization plan (JGW-T1605353)

    • NoiseBudget [Kambara]

      • results agreed with Tatsumi Simulink model
      • include fiber noise (fiber setup is different from Tatsumi model)

        • fiber length? how to do the wiring? {*}

        • ask LIGO people how they are fixing the cables {*}

          • no special vibration / heat treatment [from Kawabe]
      • 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

      • local oscillator phase noise (calculation method) {*}

        • discuss with Aso and redo calculation
  • Magnetic noise, actuator noise calculation for cryogenic payload

    • magnetic noise JGW-T1504459 [Shimoda]

    • actuator noise and range calculation on going [Miyamoto(JGW-G1605746), Okutomi] {*}

      • TM actuator efficiency should be less than 1.5 mN/A from noise point of view
      • if 1.5 mN/A, RMS velocity should be smallter than 0.04 um/sec
        • simulation on-going [Okutomi]

  • Requirement on actuator range for IMMT [Ohishi] {*}

    • magnet size: 2 mm dia, 5 mm long
    • coil turns: 39?
    • this gives 4 times larger efficiency than the IMC coil efficiency
    • IMMT resonant frequencies: pitch ~1.8 Hz, yaw ~1.5 Hz

    • this gives 50/sqrt(2) mm * (1.4e-3 N/A * 4) * 4 magnets * 1/80 A/V / 9.6e-4 kg*m2　 / (2*pi*1.8 Hz)2 = 8e-5 rad/V efficiency in pitch

    • is this enough?
      • IMC mirror (Type-C + stack) drift in yaw was less than 1 mrad/month, pitch was much less [Nakano]
      • iKAGRA ETM (Type-C w/o stack) drift was ???
  • 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)

    • MIF agreed to use 32 MHz and 33 MHz for ALS sidebands JGW-T1605626

    • may be IMC sideband (and ALS sidebands) should also needs to be phase locked with f1/f2/f3 to avoid "whistling noise"

    • in case of KAGRA, we don't need Frequency Doubler or Frequency Divide By Two for ALS {*}

      • is this true?
  • 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
      • budget for baffles around POY and POP were shifted to next FY [SEO]
  • 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]
    • announced to IOO mailing list
    • need to update the cabling diagram
  • 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 is TMS-like plate spring and single pendulum [Somiya]

  • Task list update (TaskList) [Michimura]

KAGRA/subgroup/ifo/MIF/Minutes20170130 (last edited 2017-01-23 11:02:34 by YutaMichimura)