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
Minutes
- 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
- MIF group agreed to move this task from IOO to MIF
- 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]
Agenda
- 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
- use 2017.10-11 to test PR-ETMY and ETMY cooling
- beam profiling plan should be compatible with vacuum plan; MIF will lead the planning
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]
Quad IQ Demodulator LSC JGW-T1605487
Quad IQ Demodulator ASC JGW-T1605488
High Power Coil Driver JGW-T1605489
RF Distribution Amplifier JGW-T1605490
Common Mode Servo Board JGW-T1605491
Frequency Doubler JGW-T1605492
- Quad IQ Demodulator heat-up issue
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]