ISC Meeting on 2017/10/23 14:00 - 15:00
Participants: Hirose, Kohei Yamamoto, Hiro Yamamoto, Koji Arai, Somiya, Enomoto, Koji Nagano, Aso, Michimura
eZuce meeting: "KAGRA ISC Meeting" in the KEK community.
Next meeting
2017/11/6 14:00 - 15:00
Minutes
- SRM reflectivity for early phase of bKAGRA
Sensitivity calculations [Enomoto] JGW-G1707078
- Made excess noise vs input power plot necessary to achieve BNS range of 40 Mpc
- SRM reflectivity of 70% seems least demanding in terms of excess noise and input power
- A/I: redo calculation for BBH range (with estimate of event rate) [Enomoto]
- LSC noise coupling calculation on going
- UGF for auxiliary dof can be lower than 50 Hz [by Izumi]
- MICH error signal from POP instead of MICH might be better considering phase flipping [by Izumi]
- Made excess noise vs input power plot necessary to achieve BNS range of 40 Mpc
SRM surface quality [Hirose] JGW-T1707296
- MCe-level quality SRM will produce ~52 ppm (this estimate is based on surface quality without coating; coating could increase loss by x2 to x4)
- A/I: SRM loss requirement for low reflectivity SRM [Michimura,Enomoto]
- SRM metal mass [Aso]
- overall mechanical components will cost roughly ~1M JPY [Aso]
- composite mass could create unwanted resonance (at ~3 kHz in aLIGO case, with PEEK screw)
Requirements for RF AM generation [Kohei Yamamoto] JGW-G1707309
- Optickle model basically made, and checked with hand calculations
- calculations for requirements on delay line lock displacement noise, parallel EOM MZ lock displacement noise, EOM modulation phase difference, EOM imbalance on-going
- A/I: check phase noise calculations, requirements for f1 AM-PM mixed case [Kohei Yamamoto]
Agenda
bKAGRA sensitivity update [Komori] JGW-T1707038
- bKAGRA Phase 1 [Michimura]
initial alignment work starts on Oct 10; see Commissioning page
- no AS optics for Phase 1, instead use reflection REFL beam from PRM
- we have to prepare REFL optics
- height of the beam from PR/BS breadboard will be 380 mm instead of 400 mm?
bKAGRA Phase 2 schedule [Michimura] JGW-T1707079
- meeting with SEO on Sept 6
- Goal: 1 hour lock of cryogenic RSE with RF readout, probably with ASC, no sensitivity goal
- input laser power not decided
- when to swap ETM, SRM reflectivity, vacuum
- schedule adjustment between AS WFS and OMC test necessary
SRM reflectivity for early phase of bKAGRA [Enomoto] JGW-G1707078
- 50% reflectivity is better than default (85%) when input power is below ~30 W
- sensitivity with 50% SRM will be similar to that wit 85% SRM when excess noise at low frequency is x8 aLIGO O1
- therefore, 50% SRM is OK in terms of excess noise
- sensitivity for misaligning or adding extra loss with 85% SRM is worse than that for 0% SRM
- A/Is
- make a table what are necessary to reach 40 Mpc with different SRM reflectivity [Enomoto]
- check LSC (and ASC) with different SRM reflectivity and incident power [Enomoto]
- make a budget/manpower/schedule plan for SRM suspension with 2-inch mirror holder [Aso]
- since there is already a BS dummy metal mirror suspension design, making similar system for SRM should be easy
- 2-inch SRM [Michimura, Hirose]
- asking some companies for estimate
loss function estimate [Hirose] JGW-T1707296
- make an overall budget/manpower/schedule estimate to reach 40 Mpc with different SRM reflectivity [Michimura]
bKAGRA Phase 1 spare ETM quality [Hirose,Michimura] JGW-T1707281
- 60ppm scattering, 200ppm coating absorption for ETMX
- 287ppm scattering, 41ppm coating absorption for ETMY
- is this compatible with RSE?
- IMMT1 and IMMT2 transmission [Michimura, Takeda]
- IMMT2 transmission optics are too much squeezed
- IR/green steering mirrors [Michimura]
- mirrors arrived, mirror mounts and picomotor driver ordered, pedestals by Akutsu, vacuum cables by Aso
- DC QPD holder [Michimura]
beam height should be 4inch to use similar mount, with small modification of spacer (instead of 3inch in JGW-D1402607)
- RF PD, RF QPD boxes are designed for 4inch beam height
- stages are not needed for ISC DC QPD
design new ones; they can be very simple [-> Michimura?]
- calibration can be done in different ways
- put strain relief and anchors for cables to protect QPD board
- OMC and OFI [Somiya]
- look for OFI with larger aperture [Somiya]
- DC PD and DC QPD [Michimura]
- DC PD not available. Look for product with similar specs
- DC QPD available from RS
In-vacuum RF PD and RF QPD
- we need them within 1 year, considering OMC REFL and AS RF
In-vac beam-dumps
- required spec?
PSL EOM Layout re-consideration [Enomoto] (JGW-T1706748)
- Delay-line length decided to be 2.66 m (instead of 8.88 m)
- Modulation phase between f1 AM and PM is always aligned (we need this to be aligned)
Modulation index needed at each EOM is less than measured maximum index by Uehera (JGW-T1605611)
Optickle simulation by Kohei Yamamoto JGW-G1707309
- simulation on imperfections (MZ arm asymmetry, MZ lock, EOM phase difference control etc.)
- start with hand calculation, simple setups, and then to full IFO simulation
- Requirement on carrier power loss?
- Comment from Stefan Ballmer
- Similar calculation was done in LIGO in the past. Displacement noise requirement for MZ was tough (~1e-14 m/rtHz).
- Any in-air interferometer suffer from jitter and frequency noise which cannot be suppressed.
- Actuator noise modeling [Michimura,Miyamoto]
Summarized in the paper JGW-P1707051
- Needs to implement frequency noise, but FSS modeling with ALS is complicated [student!]
Discuss mirror vibration from heat link
- Meeting on July 14 [Yamada, Miyamoto, Ushiba, Michimura]
See this page for other agendas.