1. 1 Kazuhiro Yamamoto Institute for Cosmic Ray Research (ICRR) the University of Tokyo KAGRA face to face meeting University of Toyama, Toyama, Japan 1 August 2014 Cryogenic sub group

2. 2 Contribution R. Takahashi A, H. Tabaka, T. Miyamoto, K. Ono, T. Sekiguchi, Y. Sakakibara, C. Tokoku, M. Kamiizumi, U. Iwasaki, E. Hirose, A. Khalaidovski, R. Kumar, T. Uchiyama, S. Miyoki, M. Ohashi, K. Kuroda, T. Akutsu A, H. Ishizaki A, F. E. Peña Arellano A, T. Suzuki B, T. Tomaru B, N. Kimura B, S. Koike B, T. Kume B, Toyoda B, Murakami B, Terashima B, Hagiwara B, K. Tsubono C, Y. Aso C, T. Ushiba C, K. Shibata C, D. Chen D, N. Ohmae E, K. Somiya F, R. DeSalvo G, E. Majorana H, L. Naticchioni H, W. Johnson I, A. Cumming J, R. Douglas J, K. Haughian J, I. Martin J, P. Murray J, G. Hammond J, S. Rowan J, G. Hofmann K, C. Schwarz K, D. Heinert K, R. Nawrodt K, S. Goto L, M. Tanaka L, S. Ioka M, K. Nakamoto M, H. Nezuka M, KAGRA collaboration ICRR.UT, NAOJ A, KEK B, Phys.S.UT C, Astro.S.UT D, E.UT E,S.TIT F, Sannio Univ. G, INFN H, Louisiana State Univ. I, University of Glasgow J, Friedrich-Schiller-Universitaet Jena K, Jecc Torisha L, Toshiba Keihin Product Operations M, KAGRA collaboration

3. 3 0. Abstract Although there are many topics, here, I will explain recent progress and status of (1)Cryostat (2)Payload (3)Human resources. Yusuke explains cryo duct after my talk.

4. 4 Contents 1.Introduction 2.Cryostat 3.Payload 4.Human resources 5.Summary

5. 55 1. Introduction 555 3km Mozumi Y-end Sakonishi X-end Atotsu Center Vibration isolation system, Cryocooler unit, Cryostat, Cryogenic payload Schematic view of KAGRA interferometer Four mirrors of arm cavity will be cooled. Kamioka mine (Underground site)

6. 66 Outline of vibration isolation and cryostat 14 m 1. Introduction

7. 77 Cryogenic mirror Cryostat Vibration Isolation Outline of vibration isolation and cryostat 14 m 1. Introduction

8. 8 to SAS View ports Remote valve unit 4 Low vibration cryocooler unit Main LASER beam Cryostat Stainless steel t20mm Diameter 2.6m Height ~3.6m M ~ 10 ton Cryo-coolers Pulse tube, 60Hz 0.9 W at 4K (2nd) 36 W at 50K (1st) Outline of cryostat Cryogenic payload Mirror S. Koike 1. Introduction

9. 99999 2 Pulse tube cryocoolers Pulse tube cryocoolers Baffles Cryo duct(Yusuke’s talk) Outer shield (80K) Inner shield (8K) Vacuum chamber (300K) 1. Introduction

10. 10 Pulse tube cryocoolers Heat link (pure Al) Sapphire mirror (About 20K) Heat link (pure Al) Sapphire fiber 1. Introduction

11. 11 One year ago, the cryostats were moved to the warehouse near Kamioka. 11 2. Cryostat

12. 12 First cryostat will be moved to end of Y arm on the 12th-13th of August ! It will be fixed after 19th of Aug. 2. Cryostat

13. 13 Hole on radiation shield for wire from SAS. Duct to reduce radiation invasion is necessary. 13 2. Cryostat Baffles Cryo duct(Yusuke’s talk)

14. 14 Design is fixed. It is being manufactured in Mechanical Engineering Center of KEK. 2. Cryostat Ceiling of radiation shield Duct for SAS

15. 15 Main strategy of cryo payload One payload in Fiscal year 2014 (by March 2015). Design drawing Hagiwara-san (CAD operator in KEK) and Koike-san (Engineer in KEK) proceed (based on Type B payload design). 3. Payload

16. 16 Manufacturing factory We are looking for factories and found three candidates. Mechanical Engineering Center of KEK also can support. 3. Payload

17. 17 Sapphire suspension Preparation for (similar size) prototype of lop ear is in progress. We fixed design ear and cut on mirror and ask quotation. Dummy bulk (Shinkosha) 3. Payload

18. 18 Paper about thermal conductivity measurement sapphire fibers with nail heads was accepted ! 3. Payload Sapphire suspension

19. 19 Sapphire suspension Bonding technique is necessary. Two kinds of bonding (Both of them are necessary) Hydroxide Catalysis Bonding Indium Thermal resistance and mechanical dissipation must be measured. 3. Payload

20. 20 Sapphire suspension Thermal resistance of bonding (Dan, GWADW2014) Preliminary Probably, it is OK, but Dan proceeds …. 3. Payload

21. 21 Sapphire suspension Mechanical loss of indium (Dan in Jena) 3. Payload

22. 22 Sapphire suspension Mechanical loss of indium (Dan in Jena) 3. Payload Investigation is in progress …

23. 23 Sapphire suspension Dan and Rahul proceeds with calculation of thermal noise using Finite Element Method. The result is coming soon. 3. Payload

24. 24 CuBe blade spring in platform Intermediate Mass Intermediate Recoil Mass Test Mass (sapphire mirror) Platform includes CuBe spring for vertical vibration isolation. 3. Payload

25. 25 CuBe blade spring in platform Small CuBe sample to check material properties in KEK (1)Q-value (2)Temperature coefficient of Young’s modulus Fabrication for measurement was finished. We are preparing samples. 3. Payload

26. 26 CuBe blade spring in platform Large CuBe blade spring (provided by VIS group) in 1/4 cryostat in ICRR. They will be moved to KEK on the 8th of Aug. 3. Payload

27. 27 Moving mass to adjust angle of platform and intermediate mass Cryogenic test in KEK will start soon. 27 Intermediate Mass Test Mass (sapphire mirror) 3. Payload

28. 28 Fresh persons Research staff Tatsuya Kume : Lecturer (KEK) Vibration measurement, Cryo duct New a few project assistant professors (ICRR) for cryogenic payload, cryogenic mirror and so on They will start to work on the beginning of 2015 in the earliest case. 4. Human resources

29. 29 Fresh persons Graduate students (Master course) T. Miyamoto, H. Tanaka Technical staff Toyoda : Support for cryogenic experiment and Design drawing Terashima : Technician (Machining) Murakami : Technician (Welding) Hagiwara : CAD operator 4. Human resources

30. 30 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. In the first half year of 2014, 22 guests came ! 4. Human resources

31. 31 5. Summary Cryostat First and second cryostats will be installed at Y end of KAGRA site on August, respectively. Cryo duct Yusuke reports soon ! Payload One payload by March 2015 Design and search for factories are in progress. Prototype of sapphire suspension is being prepared.

32. 32 5. Summary Payload Dan Proceeds with experiment for sapphire boding techniques. KEK proceeds with various tests (CuBe spring, moving mass....) Fresh persons 1 lecturer, 2 graduate student (master course), 3 technical staffs New project assitant professors come at the January 2015.

33. 33 Thank you for your attention !

34. 34 Sapphire suspension Q of square nail head

35. 35 One fiber prototype

36. 36 Some items for future research (not perfect list) (a)Investigation material properties (Q, thermal conductivity, strength etc.) of coating, fiber and so on. (b)Sapphire bonding, Sapphire fiber clamp (c)Control and damping scheme Actuators and sensors at cryogenic temperature (d) Mechanical and thermal simulation for payload (e) Vertical spring in cryostat (f) Reduction of initial cooling time Thermal resistance of clamp.... (g) Baffles for scattered light in radiation shield (h) Assembly procedure 7. For future

37. 37 8. Summary Cryostat : Assembly is in progress. Cooling test is coming soon. Cryogenic duct : Optimum position of 5 buffles Future work : scattered light Cryocooler unit : Cooling test and vibration measurement : OK Cryogenic payload Preparation for 1/4 cryostat to check payload performance is in progress. Current main R&D topics Inital cooling time, Sapphire fiber with nail head, Coating mechanical loss, Vibration of shield

38. 38 2. Issues (1)How to assemble Details of construction, clean room …. (2)Strength Tensile strength, development of clamp, sapphire bonding … (3)Control and damping system to reduce fluctuation and instability Actuators (what and where), resonant mode (frequency and Q) and so on

39. 39 2. Issues (4)Cooling Temperature of mirror (below 20 K), initial cooling time, heat resistance of clamp … (5)Noise Thermal noise, vibration via vibration isolation system and heat links …

40. 40 After Yusuke left …. Clamp for IMPEX fibers in Jena 4. Sapphire fibers

41. 41 Profile measurement in Glasgow 4. Sapphire fibers

42. 42 Q measurement in Jena 5. Sapphire suspension Sapphire fibers with nail heads

43. 43 Outline of vibration isolation and cryostat 43 2 Pulse tube cryocoolers Pulse tube cryocoolers Baffles Cryoduct Outer shield (80K) Inner shield (8K) Vacuum chamber (300K)

44. 44 Sapphire suspension Mechanical loss of indium (Dan in Jena) Preliminary Loss angle 3. Payload

45. 45 Sapphire suspension Dan’s calculation Dan and Rahul proceeds with calculation of thermal noise using Finite Element Method. The result is coming soon. Preliminary 3. Payload