Status of Geophysics Interferometer KIW3@Academia Sinica, 1 - PowerPoint PPT Presentation

Status of Geophysics Interferometer KIW3@Academia Sinica, 1 Kouseki Miyo Mar 21, 2017 * Earthquake Research Institute ** Disaster Prevention Research Institute Institute for Cosmic Ray Research *A.Araya, *A.Takamori, **W.Morii, M.Ohashi

Contents 2 • Introduction • Subsystem • Optical system • Vacuum system • DAQ system • Observation results • Baseline monitor for KAGRA • Plan for Crustal motion compensation system • Summary

3000 m KAGRA KAGRA has a long baseline strain meter named “GIF” Introduction • Installed X arm only fixed mirror Michelson Interferometer using a • two 1500 m antisymmetric • used to provide baseline monitor for 500 m • used for geophysical observation • GIF is … 3 Y arm X arm 1000 m 1500 m We can observe the crustal motion very precisely.

4 Subsystem/ • Subsystem • Main Interferometer • Input & Output optics • Laser • Vacuum system • DAQ system Main Interferometer Vacuum system DAQ Input/Output optics Laser

5 circular - polarized • Strain signal is displayed as a 1500 １ λ/2 -ΔL +ΔL 1500 m Laser Stabilied PBS PD s - polarized GIF/ Main Interferometer p - polarized sin cos 1/4WP 1/2WP End Reflector BS Front Reflector -ΔL ＋ΔL cos sin rotation in left figure Δstrain = 2π ΔL

6 GIF/ Input & Output optics From A. Takamori Slide in ELiTES 5th meeting

7 GIF/ Laser From A. Takamori Slide in ELiTES 5th meeting

8 GIF/ Vacuum System From A. Takamori Slide in ELiTES 5th meeting

9 using unwrap function kHz for tracking rotate • Data sampling rate is 50 Basically, measurement range is not limited. Wide range measurement. ② Obtain rotate angle using arctan function ③ ① Fitting ellipse Obtain continuous strain data 
 GIF/ Convert to Strain Time [sec] Strain Angle Time [sec] PD 2 PD 1 PD 1 PD 2 motion certainly.

10 Strain 
 • DAQ is designed converting time ). ( 1 minutes delay due to a • Strain data is almost realtime data outside of KAGRA. • Client user can get the strain control. • PXI is for ADC and laser Outside mine Client user Converter NAS GIF/ DAQ Server Strage 
 LAN PXI Y arm X arm 1000 m 1500 m 500 m 3000 m • We are taking the strain data from last August. independently from KAGRA

11 Observation result/ Dec 5, 4:30 - Dec 4, 08:30 Strain 1.3e-7 7.33 hour Time DAQ monitor Solomon Islands M7.8 Solomon Islands M6.9 2016-12-09 19:10:06 UTC 2016-12-08 17:38:46 UTC 4000 km 11 • We could observe strain signal which contains earthquake.

12 model (GOTIC2) which • We are evaluating the underground information e.g. • GIF observed local place effect. 2006 ) mountain. ( Takemoto et al. located on same KAGRA 100 m laser strainmeter • This effect was evaluated by ( × 0.9 ). includes under ground effect consistents with theoretical Result/ Comparison of Theoretical model • Measured strain signal 1e-7 Time [hour] GOTIC2×0.9 GOTIC2 Measurement 時間 [hour] Strain 12 inhomogeneous, shape of the tunnel.

13 Observation result/ Sensitivity • Lowest back ground, especially around 1-10 mHz Frequency [Hz] Strain [1/√Hz] GIF Earth 
 Tide microseismic

14 Baseline Monitor for KAGRA • The same as GW detector, GIF’s sensitivity is getting worse above a few Hz. ( ~ 7 Hz ). • Fortunately, We can directly measure 
 microseismic ( ~ 0.1 Hz < 7 Hz ) which is the biggest reason of GW detector instability. • GIF also measure lower frequency crustal motion. Seismometer can’t measure below mHz. • Because GIF can measure low frequency and directly unlike seismometer, GIF data is a good baseline monitor for KAGRA.

15 Baseline Monitor/ Crustal Motion Compensation • Feedforward CARM and DARM which converted from the X and Y arm crustal motion signal to wide range actuator e.g. LVDT at Type-A. • However, we have only X arm. • First, We compensate only CARM. • We can calculate CARM using coupling matrix of KAGRA mountain (Takemoto et al. 2006)

16 Apl Activate Crustal Motion Compensation System Design Control Scheme Commissioning Complete baseline monitor for KAGRA Prepare KAGRA DAQ Make Program for realtime phase converter Build Compensation system Non-Realtime Observation Restart Observation suppressing air fluctuation Some adjustment for 2017 Baseline Monitor/ Plan Apl 2020 Apl 2019 Apl 2018 Observation Phase-3（ Commissioning ） KAGRA schedule Phase-1（ Cryo Michelson ） Phase-2（ Full configuration ） Now

17 • GIF is a baseline monitor for KAGRA • We installed X arm. We are observing crustal motion • We are planning the crustal motion compensate system Summary