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]

  • http://klog.icrr.u-tokyo.ac.jp/osl/?r=4377

  • 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

  • http://klog.icrr.u-tokyo.ac.jp/osl/?r=3848

• 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

  • https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=7659

• Schunupp asymmetry measurement

  • http://klog.icrr.u-tokyo.ac.jp/osl/?r=4949

  • http://klog.icrr.u-tokyo.ac.jp/osl/?r=4960

• 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]

  • http://klog.icrr.u-tokyo.ac.jp/osl/?r=4176

Suspension characterization

• length actuation efficiency measurements for BS, comparison with expectations

  • http://klog.icrr.u-tokyo.ac.jp/osl/?r=4811

  • http://klog.icrr.u-tokyo.ac.jp/osl/?r=4909

• length actuation efficiency measurements for ETMX and Y, comparison with expectations

  • http://klog.icrr.u-tokyo.ac.jp/osl/?r=4898

  • http://klog.icrr.u-tokyo.ac.jp/osl/?r=4899

  • http://klog.icrr.u-tokyo.ac.jp/osl/?r=4919

  • http://klog.icrr.u-tokyo.ac.jp/osl/?r=4925

• seismic attenuation ratio measurements for ETMY and Y

  • http://klog.icrr.u-tokyo.ac.jp/osl/?r=4927

• 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

  • http://klog.icrr.u-tokyo.ac.jp/osl/?r=4775

• 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.
• Noise budget

  • http://klog.icrr.u-tokyo.ac.jp/osl/?r=4834

  • http://klog.icrr.u-tokyo.ac.jp/osl/?r=4910

  • http://klog.icrr.u-tokyo.ac.jp/osl/?r=4944

• magnetic and acoustic noise from PEM injection (details -> PEM paper?)

  • http://klog.icrr.u-tokyo.ac.jp/osl/?r=4891

  • http://klog.icrr.u-tokyo.ac.jp/osl/?r=4933

  • http://klog.icrr.u-tokyo.ac.jp/osl/?r=4871

  • http://klog.icrr.u-tokyo.ac.jp/osl/?r=4940

  • http://klog.icrr.u-tokyo.ac.jp/osl/?r=4954

• 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.

  • http://klog.icrr.u-tokyo.ac.jp/osl/?r=4948

  • http://klog.icrr.u-tokyo.ac.jp/osl/?r=4955

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)

  • http://klog.icrr.u-tokyo.ac.jp/osl/?r=4942

• 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

Data acquisition, data transfer

• latency, speed, total amount

Hardware injection test

• CBC injection(2018/4/30 Night shift)
• CW injection(2018/5/2 Night shift)

  • CW Injection