Status of the Largescale Cryogenic Gravitational Wave Telescope

Status of the Large-scale Cryogenic Gravitational Wave Telescope Project KAGRA Kazuhiro Yamamoto on behalf of KAGRA collaboration Department of Physics, University of Toyama 2017 September 13 The meeting of Physical Society of Japan @Mine campus, Utsunomiya University, Utsunomiya, Tochigi 1

Gravitational wave 1916 : A. Einstein predicted gravitational wave (General relativity) A. Einstein(Wikipedia) 2015 : LIGO detected gravitational wave directly. LIGO open science center 2

In last two years What happened so far ? Observation period O 1 : 2015 Sep 12 - 2016 Jan 19 O 2 : 2016 Nov 30 - 2017 Aug 25 Three events (binary black hole coalescences) Physical Review Letters 116(2016)061102. Physical Review Letters 116(2016)241103. Physical Review Letters 118(2017)221101. Virgo joins O 2 (2017 Aug 1 - 25) LIGO and Virgo have one year break for improving. 3

After O 2 LIGO Scientific Collaboration News 25 August 2017 -- The Virgo and LIGO Scientific Collaborations have been observing since November 30, 2016 in the second Advanced Detector Observing Run ‘O 2’ , searching for gravitational-wave signals, first with the two LIGO detectors, then with both LIGO and Virgo instruments operating together since August 1, 2017. Some promising gravitationalwave candidates have been identified in data from both LIGO and Virgo during our preliminary analysis, and we have shared what we currently know with astronomical observing partners. We are working hard to assure that the candidates are valid gravitational-wave events, and it will require time to establish the level of confidence needed to bring any results to the scientific community and the greater public. We will let you know as soon we have information ready to share. http: //www. ligo. org/news. php 4

Next step (1)Better sensitivity : Plans for 3 rd generation (10 times better sensitivity than current 2 nd generation) (2)Many other detectors for finer direction resolution KAGRA : 2 nd generation detector in Japan (Kamioka) Unique key features : Underground site with small seismic motion Cooled mirror and its suspension to reduce thermal noise -> 3 rd generation adopts these idea. 5

KAGRA timeline Phase 2 300 K Phase 1 6

感度の進展予想 Based on Living Reviews in Relativity 19, 1 (2016) year 7 2026 2025 2024 2023 2022 2021 2020 2019 2018 2017 2014 100 2016 1000 LIGO Voyager(米) どのように世界一を目指すか ？ e どのようにいち早く d ra g 重力波観測に加わるか？ up KAGRA+? design Ad. V+? O 3 design a. LIGO(米) O 2 design O 1 O 3 Ad. V(欧) O 2 KAGRA(日) 2015 BNS inspiral range [Mpc] Y. Michimura 13 a. S 35 2 • KAGRAはどのように感度を上げていくか？ 7

Vibration isolation and cryostat Design drawing with tunnel and cross section 2 nd floor A. Hagiwara 14 m Shaft Clean booth Vacuum ducts along laser beam Cryostat 8

Vibration isolation and cryostat A. Hagiwara Vibration isolation system (room temperature) Cryogenic payload (Mirror is on bottom side of payload) 9

Vibration isolation and cryostat Finally, we installed this vibration isolation and cryogenic payload (almost same as practical one) at one end station. A. Hagiwara Vibration isolation system (room temperature) Cryogenic payload (Mirror is on bottom side of payload) 10

Vibration isolation and cryostat Cryogenic payload Mirror and payload was cooled down (12 K, initial cooling time is 23 days). A part of vibration isolation 11

Cryogenic payload Performance test T. Miyamoto 13 p. U 34 4 Vibration measurement T. Ochi 13 p. U 34 2 Heat link T. Yamada 13 p. U 34 3 Mirror 12

Sapphire mirror Mirror contamination (residual gas) K. Hasegawa 13 p. U 34 5 Absorption in mirror M. Manuel 14 a. U 11 11 Ears bonding to suspend mirror T. Ushiba 13 p. U 34 1 13

161207_SAITO Vibration isolation BRT Type-A system ETM - Cryogenic test mass Sapphire, 23 kg, 20 K - Tall seismic isolator IP + GASF + Payload Y-arm b. KAGRA phase-I (- Mar 2018) R. Takahashi 13 a. S 35 3 ITM MC PRM Type-C system - Mode cleaner Silica, 0. 5 kg, 290 K - Stack + Payload BS BRT IO A. Shoda 13 a. S 35 5 Type-Bp payload ITM ETM Type-B system SRM OMMT OMC Test mass and Core optics (BS, FM, . . ) Silica, 10 kg, 290 K - Seismic isolator Table + GASF + Type-B Payload - X-arm - Core optics (BS, SRM, …) Silica, 10 kg, 290 K - IP + GASF + Payload - Stack for aux. optics M. Barton 13 a. S 35 4 14

Current status of VIS Type-A Y-End: Installed. Cooling test of the cryogenic payload is on going. X-End: Installation work is on going. Setting the Filter 1 stage now. Type-B BS test hanging was finished. Real BS installation is on going. Type-Bp PR 2 & PR 3 have been installed. PRM installation is on going. BS payload with assembly frame. Installation of PR 2. Bottom filter and dummy payload 15 in Y-end.

Vibration isolation and ground motion Crackling noise in vibration isolation system M. Kirii 13 p. U 34 12 Compensation of slow motion of ground K. Miyo 13 a. S 35 6 16

Component of interferometer 161207_SAITO BRT ETM Y-arm Intensity stabilization Green lock University of Toyama Transmission monitor system T. Akutsu on behalf of T. Morozumi 13 a. S 35 7 ITM MC PRM BS X-arm BRT IO ITM SRM OMMT OMC ETM Output mode cleaner J. Kasuya 13 a. S 35 8 17

Intensity stabilization University of Toyama Achieved noise reduction 30 d. B @ 30 Hz 35 d. B @ 100 Hz

Intensity stabilization University of Toyama

Green lock PDH 40 Mhz PLL PD EOM SHG Laser 2 Optical fiber AOM PD PR 2 BS Laser 1 University of Toyama PR 3 X-Armcavity

Green lock Experiment of PLL system University of Toyama Beatnote Frequency divider Beatnote is locked at 129 MHz

Component of interferometer 161207_SAITO BRT ETM Y-arm Intensity stabilization Green lock University of Toyama Transmission monitor system T. Akutsu on behalf of T. Morozumi 13 a. S 35 7 ITM MC PRM BS X-arm BRT IO ITM SRM OMMT OMC ETM Output mode cleaner J. Kasuya 13 a. S 35 8 22

Transmission monitor system T. Akutsu on behalf of T. Morozumi 13 a. S 35 7 23

Component of interferometer 161207_SAITO BRT ETM Y-arm Intensity stabilization Green lock University of Toyama Transmission monitor system T. Akutsu on behalf of T. Morozumi 13 a. S 35 7 ITM MC PRM BS X-arm BRT IO ITM SRM OMMT OMC ETM Output mode cleaner J. Kasuya 13 a. S 35 8 24

Calibration is always crucial point in experiments ! Calibration of gravitational wave detector : < 1% Photo calibrator shakes mirror for calibration. (Back action (momentum) of reflected light). Overview Y. Inoue 13 a. S 35 11 26

Power modulation Bin-Hua. Hsieh. 13 a. S 35 12 Camera (beam spot) T. Shishido 13 a. S 35 13 27

Calibration How to calibrate with calibrator ? Signal injection test T. Yokozawa 13 a. S 35 11 Calibration in i. KAGRA T. Yamamoto 13 a. S 35 10 28

Data transfer

Data analysis Test run Data analysis is in progress. 300 K 31

Binary coalescence search and correlation analysis M. Sasai 15 a. U 31 2 Noise characterization H. Yuzurihara 15 a. U 31 1

Summary Gravitational wave was detected. We need more detectors for astronomy : KAGRA b. KAGRA phase 1 : by March 2018 Cryogenic Michelson interferometer operation We strongly proceed with preparation, installation, development, and investigation. Details of KAGRA are presented today. Some talks will be tomorrow or the day after tomorrow. 33

Thank you for your attention ! 34