= ISC Meeting on 2016/9/5 14:00 - 15:00 =
Participants: Michimura, Enomoto, Arai, Aso, Haino, Miyakawa
=== Next meeting ===
2016/9/20 14:00 - 15:00
[[LCGT/subgroup/ifo/ISC/Meetings|back to Meetings page]]
== Minutes ==
* bKAGRA Phase 1 optical configuration study [Michimura]
* ASC sensing matrix for [[http://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=5362|JGW-T1605362]] was updated to reflect PR2-PR3 length decision [Enomoto]
* summary of Phase 1 study [Michimura] ([[http://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=5595|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
* beam shutter engineering could be very tough
* RF generation scheme [Michimura]
* ALS sideband frequencies [[http://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=5626|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
* exp(-2*(188/2/35.3)^2) = 0.7 ppm scattering from recoil mass is smaller than 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] ([[http://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=5362|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 [[https://dcc.ligo.org/LIGO-G080467|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] ([[http://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=5595|JGW-T1605595]])
* bKAGRA Phase 1 initial alignment / commissioning plan [Michimura]: [[http://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/DocDB/ShowDocument?docid=5274|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 ([[KAGRA/Subgroups/MIF/AEL|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 [[https://dcc.ligo.org/LIGO-D1000124/public|LIGO-D1000124]], but we will omit [[https://dcc.ligo.org/LIGO-D1000064/public|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? [[https://dcc.ligo.org/LIGO-D1002178/public|LIGO-D1002178]]
* Output optical tables [Michimura] ([[KAGRA/Subgroups/IOO/OutputTables|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 ([[http://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=5493|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? [[http://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=5626|JGW-T1605626]]
* Arm Length Stabilization plan ([[http://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=5353|JGW-T1605353]])
* Noise``Budget [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? ([[https://dcc.ligo.org/LIGO-T1000090|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: [[http://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=5334|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 ([[KAGRA/Subgroups/MIF/TaskList|TaskList]]) [Michimura]