Summary of Phase 1 Measurements
- Summary of Phase 1 measurements for bKAGRA Phase 1 paper.
Basic configurations
- Duration
- officially (as Saito-san mentioned): Apr 28 9:00am to May 7 6:00am (GPS time: 1208908818-1209675618)
- input power [Kokeyama, Nakano]
- 0.93W at PSL output
- IMC coupling ratio is (1.20-0.72) / (1.20 - 0.25) = 51 %
- this means 0.93W * 0.51 / 10 / 2 / 2 / 10 = 1.2 mW at REFL, 0.6 mW at REFL RD PD
- power at detection RF PD
Reflection from one end mirror 0.20 mW (http://klog.icrr.u-tokyo.ac.jp/osl/?r=4876)
At dark fringe 56 +/- 10 uW (http://klog.icrr.u-tokyo.ac.jp/osl/?r=4903)
signal chain (http://klog.icrr.u-tokyo.ac.jp/osl/?r=4920)
- modulation frequency, modulation depth
16.87293 MHz (http://klog.icrr.u-tokyo.ac.jp/osl/?r=4831)
beta = 0.12 (from error signal amplitude), 0.2 (from RF power applied to EOM) (http://klog.icrr.u-tokyo.ac.jp/osl/?r=4876 , http://klog.icrr.u-tokyo.ac.jp/osl/?r=4907)
- RFPD transimpedance measurement was done with RFPD with different S/N.
- vacuum pressure [info from Y. Saito]
- Xend 3e-4 Pa (room temp)
- Xarm 7e-6 Pa
- Xfront 5e-5 Pa (room temp)
- Yend 2e-5 Pa (cryo)
- Yarm ~1e-6 Pa? (no monitors)
- Yfront 8e-5 Pa (temperature rising started on Apr 28)
IMC, BS < ~1e-4 Pa (no monitors)
suspension and coil driver configurations (difference between the final configuration in ActuatorDesign)
- BS IM and TM use high power coil drivers instead of low power.
- ETMY MN, IM and TM use high power coil drivers instead of low power.
- ETMX MN and IM V1/2 use high power coil drivers instead of low power. From May 4 or 5, IM H1/2/3,V3 also uses high power. ETMX TM used the default low power (not cryopayload version).
Michelson initial alignment
- details of slit method
- slit size ~10mm, at C chamber first, and then A chamber
Tcam and baffle PD performance (details-> Tcam paper)
- Tcam update frequency ~1sec, resolution [Inoue]
- Tcam resolution?
- successfully monitored the beam under cryo baffles/shields
Installation accuracy
- initial alignment
- Schnupp asymmetry measurement
- IMC length measurement
53.30299(2) m (http://klog.icrr.u-tokyo.ac.jp/osl/?r=4831)
Cryogenics
cooling curve (details -> CRY paper) [Hasegawa?]
- Platform, MN, IM, TM, shields
- alignment drift, height change during the cool down
- height change [Inoue]
- not much info for alignment drift. O(100)urad in yaw [Izumi]
Suspension characterization
- length actuation efficiency measurements for BS, comparison with expectations
- length actuation efficiency measurements for ETMX and Y, comparison with expectations
- seismic attenuation ratio measurements for ETMX
- TF difference between ETMX and ETMY (room temperature and cryogenic)
- vertical to length coupling, other coupling measurements
- for BS [Fujii]
Sensitivity and stability
- actuation efficiency drift [Yamamoto]
- alignment drift of suspensions
- visibility and optical gain drift
sensitivity stability, duty factor, lock duration (similar plots in https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=5177)
- duty factor
- Total: 68.65%
- 4/28: 81.66%
- 4/29: 97.00%
- 4/30: 90.36%
- 5/01: 87.09%
- 5/02: 86.88%
- 5/03: 19.97%
- 5/04: 33.58%
- 5/05: 64.18%
- 5/06: 55.36%
- Michelson was lockable if ETMX/Y angular fluctuation is less than a few urad. Earthquakes shook ETMY to O(100) urad.
- duty factor
- Noise budget
magnetic and acoustic noise from PEM injection (details -> PEM paper?)
- Earthquake in Hawaii 2018-05-04 22:32:55 (UTC)
- difference between iKAGRA and Phase-1?
- ETMY takes ~2-3 hours to damp enough for locking. ETMX takes ~1 hour.
- difference between iKAGRA and Phase-1?
calibration JGW-G1808320 JGW-G1808989
Seismic noise, arm length drift
seismic spectra stability (similar plots in https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=2971)
- differential seismic noise measured by Michelson (3-km CMRR), GIF-X (1.5-km CMRR), IMC (26.65-m CMRR)
- CMRR measurement with 3-km Michelson would be difficult
- IMC CMRR [Nakano]
- differential arm length drift, correlation between GIF-X
air pressure JGW-G1808316
Data acquisition, data transfer
- latency, speed, total amount
Data rate ~5.1MB/sec (main), ~6.6MB/sec (all) JGW-G1808320
Hardware injection test
- CBC injection(2018/4/30 Night shift)
- CW injection(2018/5/2 Night shift)