Status of KAGRA Cryogenics II Kazuhiro Yamamoto, Kieran Craig, Takaaki Kajita, Takahiro Miyamoto, Hiroki Tanaka, Ayako HagiwaraA, Nobuhiro KimuraA, Rahul KumarA, Toshikazu SuzukiA, Takayuki TomaruA, Ayako UedaA, Takafumi UshibaB, Junko KasuyaC, Suguru TakadaD, Sadakazu HainoE, Yuki InoueE, Ettore MajoranaF, Helios VoccaG, KAGRA Cryogenics Subgroup ICRR, AKEK, BPhys.S.UT, CTITEC, DNIFS, EAcademia Sinica, FINFN Rome, GINFN Perugia 2016 September 22 The meeting of Physical Society of Japan @Kihana campus, University of Miyazaki, Miyazaki, Miyazaki 1 1 1 1

0. Abstract Here, I explain Current status of (1) Cryostats at site (2) Cryogenic payload 2

Contents Introduction Cryostats at site Cryogenic payload Summary 3

1. Introduction Schematic view of KAGRA interferometer Four mirrors of arm cavity will be cooled. 3km 3km Mozumi Y-end Sakonishi X-end Kamioka mine (Underground site) Atotsu Center Vibration isolation system (Type A), Cryocooler unit, Cryostat, Cryogenic payload 4 4 4 4 4 4 4 4

Vibration isolation system Vacuum ducts along laser beam 1. Introduction Outline of vibration isolation and cryostat Design drawing with tunnel and cross section 2nd floor A. Hagiwara Vibration isolation system (room temperature) 14 m Shaft Clean booth Vacuum ducts along laser beam Cryostat (Here the mirror is) 5 5 5

1. Introduction Schematic view of cryo-payload Sapphire suspension Pulse tube cryocoolers Pulse tube cryocoolers Sapphire fiber Cryo-payload Sapphire mirror (About 20K)

1. Introduction Schematic view of cryo-payload Sapphire suspension Pulse tube cryocoolers Pulse tube cryocoolers Cryo duct

2. Cryostats at site We must conduct cooling test of all cryostats by March 2017. So far, at both ends, missions for assembly and connection were over. Leak check is current main mission at both ends. Mission for two cryostats in center room will be started on November.

2. Cryostats at site So far, at both ends, missions as below were over. Installation of duct shield and 80K cryocooler units A. Hagiwara Cryostat (Here the mirror is)

2. Cryostats at site So far, at both ends, missions as below were over. Installation of duct shield and 80K cryocooler units

2. Cryostats at site So far, at both ends, missions as below were over. (2) Connection 4K cryocoolers unit to each cryostats to SAS Outline of cryostat 4 Low vibration cryocooler unit Remote valve unit S. Koike 11

2. Cryostats at site So far, at both ends, missions as below were over. (2) Connection 4K cryocoolers unit to each cryostats to SAS

2. Cryostats at site So far, at both ends, missions as below were over. (3) Connection of 900 cross duct A. Hagiwara Cryostat (Here the mirror is) 13

2. Cryostats at site So far, at both ends, missions as below were over. (3) Connection of 900 cross duct 14

2. Cryostats at site So far, at both ends, missions as below were over. (3) Connection of 900 cross duct 15

3. Cryogenic payload Outline of vibration isolation and cryostat Pulse tube cryocoolers Pulse tube cryocoolers Cryo-payload 16 16 16 16 16 16 16

3. Cryogenic payload Outline of vibration isolation and cryostat Platform Recoil mass for Marionette Recoil mass for intermediate mass Recoil mass for mirror A. Hagiwara 17 17

3. Cryogenic payload The first cryogenic payload has already been delivered and assembled ! Performance test (adjustment and control system, measurement of transfer function) is in progress or being prepared. 18 18 18 18 18 18 18 18 18

3. Cryogenic payload Outline of cryogenic payload Mirror chain Platform Recoil mass chain Marionette Intermediate mass Thermal noise caused by recoil mass chain is small. Sapphire Mirror http://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=2106 19 19 19 19 19 19 19

3. Cryogenic payload Outline of cryogenic payload GAS filer Platform for vertical vibration isolation (Mirror chain is suspended) Platform Marionette Intermediate mass Sapphire Mirror 20 20 20 20 20 20 20

3. Cryogenic payload Outline of cryogenic payload Platform Alignment adjustment system Platform Marionette Simple system for high Q-value of sapphire suspension Intermediate mass Sapphire Mirror 21 21 21 21 21 21 21

3. Cryogenic payload Outline of cryogenic payload Platform Sensor and actuator (for control and damping) Marionette Intermediate mass Sapphire Mirror 22 22 22 22 22 22 22

3. Cryogenic payload Sapphire lop-eared suspension “Sapphire monolithic lop-eared suspension” One of the most important parts of KAGRA : Main sapphire mirrors are included. All parts are made from sapphire. 23

3. Cryogenic payload Blade spring Fiber with nail head on both ends Sapphire lop-eared suspension Blade spring (compensation of fiber length difference) Fiber with nail head on both ends Flat cut Nail head of fiber Mirror Ear A. Hagiwara

3. Cryogenic payload Sapphire lop-eared suspension Indium bonding on both nail heads of fiber When fibers are broken, they can be removed ! Hydroxide Catalysis Bonding between ear and mirror

3. Cryogenic payload We expect that all of main parts of cryogenic payload will be delivered by March 2017 as schedule. Two sapphire mirrors for end stations (End Test Mass) will be delivered for assembly of cryogenic payload on February 2017. September- December 2017 : Installation at both end stations We must strongly proceed with prototype test and development. 26 26 26 26 26 26 26 26

3. Cryogenic payload Current hot topics (presentations in this session) Design of control system for cryogenic payload T. Miyamoto’s talk 27 27 27 27 27 27 27 27

3. Cryogenic payload Current hot topics (presentations in this session) R. Kumar’s talk 28 28 28 28 28 28 28 28

3. Cryogenic payload Current hot topics (presentations in this session) Assembly sapphire suspension (Bonding between ears and mirror) K. Craig’s talk (K. Yamamoto presents on behalf of him) 29 29 29 29 29 29 29 29

3. Cryogenic payload Current hot topics (presentations in this session) Heat load test with simplified (one fiber) prototype Sapphire blade spring H. Tanaka’s talk Sapphire fiber 6kg sapphire mass (1/4 of KAGRA mirror) D. Chen 30 30 30 30 30 30 30 30

3. Cryogenic payload Current hot topics (presentations in this session) Measurement of Q-values of sapphire blade spring T. Ushiba’s talk 31 31 31 31 31 31 31 31

4. Summary Cryostats at site Cooling test of all four cryostats by March 2017 Assembly and connection at both ends were over. Leak test at both ends is in progress. Cryogenic payload Procurement of main parts by March 2017 Installation at both ends on September-December 2017 We must strongly proceed ! Hottest topics will be presented by next 5 speakers. 32

Thank you for your attention ! 33

Backup 34

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3. Cryogenic payload Outline of cryostat Cryogenic payload Mirror to SAS Cryogenic payload Cryostat Stainless steel t20mm Diameter 2.6m Height ~3.6m M ~ 10 ton Mirror View ports 4 Low vibration cryocooler unit Cryo-coolers Pulse tube, 60Hz 0.9 W at 4K (2nd) 36 W at 50K (1st) Main LASER beam Remote valve unit S. Koike

3. Cryogenic payload Outline of vibration isolation and cryostat Heat link (pure Al) Heat link (pure Al) Pulse tube cryocoolers Pulse tube cryocoolers Cryo-payload 37 37 37 37 37 37 37

3. Cryogenic payload Design A. Hagiwara proceeds with Without recoil chain Design A. Hagiwara proceeds with CAD design drawings. Almost all parts except for platform were designed. Design is based on discussion with Vibration Isolation subgroup of KAGRA. Marionette Platform Intermediate mass Mirror A. Hagiwara 38 38

3. Cryogenic payload Prototype test of cryogenic payload Two differences from actual one Platform does NOT include GAS filter. Mirror and fibers are NOT made from sapphire, but metal. 39

3. Cryogenic payload Prototype test of cryogenic payload Without recoil chain Prototype test of cryogenic payload Marionette, Intermediate mass, Dummy mirror, Recoil mass For (dummy mirror) has already been delivered. Marionette Intermediate mass Dummy Mirror (and recoil mass) A. Hagiwara 40 40

Acknowledgement ELiTES: ET-LCGT interferometric Telescope Exchange of Scientists Grant for collaboration about cryogenic between KAGRA and ET European 7th Framework Programme Marie Curie action (Mar. 2012 - Feb. 2016) European people can visit Japan for KAGRA. 41 41 41

2. Sapphire suspension All sapphire parts for full size prototype have already been delivered (IMPEX and Shinkosha). Sapphire cylinder with flat cuts as dummy mirror Fibers with nail head Blade spring Ears 42 42 42 42 42 42 42 42

2. Sapphire suspension One fiber prototype 6kg mass (copper) (1/4 of KAGRA mirror) Sapphire blade spring Nail head of sapphire fiber Support frame 43

2. Sapphire suspension One fiber prototype Sapphire blade spring Dummy Cu wire Sapphire mass D. Chen, J. Komma, H. Tanaka, Y. Liu

2. Sapphire suspension One fiber prototype Now, it is in cryostat and first (primitive) cooling test is in progress. 45