Overv rview of f KAGRA Masatake OHASHI (ICRR) on behalf of KAGRA - PowerPoint PPT Presentation

Overv rview of f KAGRA Masatake OHASHI (ICRR) on behalf of KAGRA collaboration Overview of KAGRA 1

First of all … This talk is an index of the 10 KAGRA related talks. KAGRA related talks ・ Cryogenic system at underground site for Large-scale Cryogenic Gravitational Wave Telescope, KAGRA ・ Vibration Isolation System for the Cryogenic Mirrors in KAGRA ・ Interferometer control of KAGRA ・ Global control using a laser strainmeter for KAGRA ・ Construction and the operation of the interferometer control system and the DAQ system for KAGRA ・ Investigation of the environment influence for the underground and cryogenic gravitational wave detector, KAGRA ・ Detector Characterization for the underground-based gravitational-wave detector, KAGRA ・ Newtonian noise from the underground water ・ KAGRA Data Tiers ・ Overview of KAGRA Data Analysis Overview of KAGRA 2

General outline of f KAGRA Pro roject KAGRA is 3km L-shaped underground laser interferometer with cryogenic mirrors Project framework ・ ICRR hosts this project, and KEK and NAOJ co‐host it to construct KAGRA for gravitational wave astronomy. Univ. of Toyama supports the project. Purpose of this project ・ To understand astronomical phenomena like supernova explosion and coalescence of binary compact stars with gravitational waves Overview of KAGRA 3

Schedule of f KAGRA Pro roject Calendar year 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 Project start Tunnel Excavation 3km Michelson Interferometer iKAGRA iKAGRA First operation 3km Cryogenic Interferometer bKAGRA Final installation Commissioning and Observation Overview of KAGRA 4

Designed sensitivity of KAGRA Duty factor: > 80% Inspiral range: 153 Mpc Overview of KAGRA 5

Two key features of f KAGRA 1. KAGRA is constructed at underground site. 2. KAGRA uses cryogenic mirrors. Overview of KAGRA 6

Seismic noise in in Kamioka Mine Seismic noise is serious for GW detection. Underground site Is very quiet. So we selected underground site for KAGRA. Overview of KAGRA 7

Tunnel Excavation 3 corner stations are complicated because of tall towers for Vibration Isolation Systems. Overview of KAGRA 8

Dif ifficulty of f Underground sit ite Springwater Overview of KAGRA 9

Spring water fr from wall surfaces All surfaces were covered by waterproof sheets. It took 4 years to overcome spring water in the tunnel. Overview of KAGRA 10

Two key features of f KAGRA 1. KAGRA is constructed at underground site. 2. KAGRA uses cryogenic mirrors. Overview of KAGRA 11

Thermal noises The sensitivity of interferometer around 100Hz is ordinarily limited by thermal noises. Overview of KAGRA 12

Mirror th thermal noise Amplitude of thermal noise is proportional to ( T/Q ) 1/2 In general, Q (inverse number of magnitude of dissipation) depends on T (temperature). Sapphire Q becomes highest at low temperature. Therefore KAGRA mirrors use sapphire substrates and are cooled to around 20K. Overview of KAGRA 13

Cry ryogenic mir irror suspension system ~ 14 m Overview of KAGRA 14

Cry ryogenic payload Mirror was cooled below 20K type A Cryogenic payload with mirror Overview of KAGRA 15

In International Network for GW Observ rvation It is necessary to determine the direction of GW sources. Advanced LIGO GEO600 Hanford KAGRA Advanced LIGO Advanced Livingston Virgo LIGO-India (anticipated) Overview of KAGRA 16

Jo Joint Run Planning wit ith LI LIGO and Vir irgo KAGRA plans to join O3 in this year. Overview of KAGRA 17 KAGRA 17

Summary • In the spring of 2019, we completed the construction phase and moved on to the commissioning phase. • KAGRA plans to join O3 in this year. Overview of KAGRA 18 18