1. 1 Kazuhiro Yamamoto Institute for Cosmic Ray Research (ICRR) the University of Tokyo Einstein Telescope Meeting 2013 Albert Einstein Institut Hannover, Hannover, Germany 22 October 2013 Cryogenic payload for KAGRA

2. 2 Contribution R. Takahashi, 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, N. Kimura B, S. Koike B, T. Kume 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.D. 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, but here, I will explain (1)Experiments in KAGRA cryostat (2)Monolithic sapphire suspension

4. 4 Contents 1.Introduction 2.Experiments in KAGRA cryostat 3. Sapphire suspension 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 (K. Kuroda’s talk) Four mirrors of arm cavity will be cooled. Kamioka mine (Underground site)

6. 6 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 1. Introduction S. Koike N. Kimura’s talk

7. Outline of vibration isolation and cryostat 77777 Pulse tube cryocoolers Heat link (pure Al or Cu) Sapphire mirror (About 20K) Heat link (pure Al or Cu) Sapphire fiber 1. Introduction

8. 8 Main topics Experiments in KAGRA cryostat Initial cooling time Measurement of radiation vibration Sapphire monolithic suspension Key component of KAGRA 1. Introduction

9. KAGRA cryostats have already been assembled ! at Toshiba Keihin Product Operations 9 2. Experiments in KAGRA cryostat

10. Cooling test : Can cryostats be cooled well ? Cooling test for all four KAGRA cryostats January 2013 – April 2013 Cooling test for the 3rd cryostat July 2013 – August 2013 10 2. Experiments in KAGRA cryostat

11. 11 Experiments in cooling test of KAGRA cryostat Experiment 1 : Initial cooling time of cryogenic payload This initial cooling time should be short. Experiment 2 : Measurement of shield vibration This vibration causes motion of mirrors and scattered light noise. Dan Chen presents poster in this meeting. 2. Experiments in KAGRA cryostat

12. 12 At beginning of initial cooling, heat transfer is dominated by radiation. Initial cooling time of cryogenic payload is about 2 months (if no tricks). Diamond Like Carbon (DLC) coating (or SolBlack) (High emissivity, Large radiation) on shields and payload (except for mirror) Experiment 1 : Initial cooling time 2. Experiments in KAGRA cryostat

13. 13 Yusuke Sakakibara’s calculation Experiment 1 : Initial cooling time about 20 days This calculation must be checked experimentally. 2. Experiments in KAGRA cryostat

14. 14 Experiment 1 : Initial cooling time Dummy payload was suspended in KAGRA cryostat. Half size Hollow masses (~5 kg) DLC coating Sapphire bulk as dummy mirror S. Koike (100 mm in diameter) Evaluation of emissivity 2. Experiments in KAGRA cryostat

15. Experiment 1 : Initial cooling time 15 Dummy payload 15 2. Experiments in KAGRA cryostat

16. 16 Experiment 1 : Initial cooling time First experiment (Spring 2013) without heat link Time [day] Payload was cooled by only radiation. Calculated result is consistent with experimental one. 2. Experiments in KAGRA cryostat

17. 17 Experiment 1 : Initial cooling time Second experiment (Summer 2013) with Cu heat link Time [day] Payload was cooled by radiation (above 150 K) and heat conduction in heat link (below 150 K). 2. Experiments in KAGRA cryostat

18. 18 Experiment 1 : Initial cooling time Second experiment (Summer 2013) with Cu heat link Problem (1) : One cryocooler temperature is 20 K (below 8 K in normal operation). Problem (2) : Thermal resistance of copper heat link is a few times larger than our expectation. Themal resistance on the both ends (solderless terminal) ? Size effect (this heat link many consists of thin wires) ? 2. Experiments in KAGRA cryostat

19. 19 Experiment 1 : Initial cooling time Second experiment (Summer 2013) with Cu heat link Themal resistance on the both ends (solderless terminal) ? Size effect (this heat link many consists of thin wires) ? 2. Experiments in KAGRA cryostat

20. 20 Experiment 1 : Initial cooling time After second experiment (Summer 2013) with Cu heat link... Plan (1)Dummy payload cooling test in 1/4 cryostat This 1/4 cryostat is to test performance of KAGRA cryogenic payload (2)Measurement of thermal conductivity (or resistance) of heat link itself 2. Experiments in KAGRA cryostat

21. 21 1/4 cryostat for perfomance test of cryogenic payload Vacuum chamber : 1.2 m in diameter, 1.6 m in height Delivery : 27th of Sep. 2013 2. Experiments in KAGRA cryostat

22. 22 Vibration of shield could be problems. Vibration via heat links, Scattered light We must measure the vibration of shield. This measurement is at cryogenic temperature and in vacuum. Luca Naticchioni (Rome) and Dan Chen (ICRR) will measure vertical and horizontal vibration of radiation shield of KAGRA, respectively. Dan Chen presents poster in this meeting. Experiment 2 : Measurement of shield vibration 2. Experiments in KAGRA cryostat

23. 23 Experiment 2 : Measurement of shield vibration Dan Chen (horizontal motion) Analysis for sensitivity is in progress. After cooling down 10K 2. Experiments in KAGRA cryostat

24. 24 Experiment 2 : Measurement of shield vibration Luca Naticchioni (vertical motion) Analysis for sensitivity is in progress. After cooling down 10K 2. Experiments in KAGRA cryostat

25. 25 3. Sapphire suspension 25 Sapphire monolithic suspension Sapphire mirror is suspended by sapphire fibers. Key component of KAGRA We need (a)Drilled sapphire mirror (b)Sapphire fibers with nail heads (c)Bonding between bulk and fibers

26. 26 3. Sapphire suspension 26 Drilled sapphire bulk We ordered Shinkosha (test sample). KAGRA mirrors : 220 mm in diameter

27. 27 3. Sapphire suspension 27 Drilled sapphire bulk We ordered Shinkosha (test sample). It was delivered on the 1 st of October. Second sample is being made.

28. 28 3. Sapphire suspension 28 Test sample (T. Uchiyama) Sapphire fibers with nail heads are necessary to suspend mirrors.

29. 29 MolTech GmbH (Germany) and IMPEX HighTech GmbH (Germany) have already delivered ! 3. Sapphire suspension Sapphire fibers with nail heads Although the size is similar to that of KAGRA, quality check is necessary.

30. 3. Sapphire suspension 30 Sapphire fibers with nail heads Quality check under collaboration with ET (ELiTES) Q-value Measurement in Glasgow, Jena, Rome and Tokyo Thermal conductivity Measurement in Jena, Rome and Tokyo Strength Measurement in Glasgow

31. 31 Latest summary 3. Sapphire suspension Moltech IMPEX KAGRA requirement Q-value 10 7 1*10 6 5*10 6 at 20K - 6*10 6 Thermal Conductivity 3000 5000 5000 at 20K [W/m/K] -9000 Although IMPEX fiber satisfies requirement (Details are in D. Chen’s poster), further investigation is necessary (polish of nail head surface …). Sapphire fibers with nail heads

32. 32 3. Sapphire suspension Thermal conductivity of four IMPEX fibers Enough high conductivity Aleksandr Khalaidovski Ronny Nawrodt

33. 33 3. Sapphire suspension Decay motion of IMPEX fibers D. Chen’s poster Half day measurement

34. 3. Sapphire suspension Strength test Test for sapphire fibers and blades is in progress (Glasgow). Bending strength 268 MPa Alan V. Cumming’ talk

35. 35 3. Sapphire suspension 35 Bonding between sapphire fibers and sapphire mirror Investigation of Hydroxide Catalysis Bonding is in progress in Glasgow. (Rebecca Douglas, GWADW2013). Strength (about 60 MPa) measured by her is 10 times larger than those of previous papers. T. Suzuki et al., Journal of Physics; Conference Series 32(2006)309. A. Dari et al., Classical and Quantum Gravity 27(2010)045010. Other measurement (thermal resistance and so on) are necessary. Rebecca Douglas and Karen Haughian will stay in Japan (November).

36. 36 3. Sapphire suspension 36 Assembled sapphire monolithic suspension Performance of assembled monolithic sapphire pendulum must be checked. Before that, sapphire bulk is suspended by sapphire fibers using indium as thermal and mechanical contact (some kinds of “glue” instead of bonding) between sapphire bulk and fibers. We will investigate performance and obtain expertise for the monolithic pendulum test as first step.

37. 37 3. Sapphire suspension 37 Assembled sapphire monolithic suspension A.Khalaidovski designed the frame for this first step. This frame was delivered. Experiment will be started soon.

38. 38 4. Human resources 38 3 fresh persons from Europe Dr. Aleksandr Khalaidovski from Hannover, June 2013-May 2014 Sapphire monolithic suspension (Dr. Fabián Erasmo Peña Arellano from Birmingham, May 2013 – April 2016 Cryogenic sensor) Dr. Rahul Kumar from Glasgow, September 2013 – August 2014 Simulation and development of payload

39. 39 4. Human resources 39 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.

40. 40 4. Human resources 40 7 visitors supported by ELiTES in the first three quaters of 2013 Christian Schwarz, Gerd Hofmann, Ronny Nawrodt (Jena) Automatic systems to measure Q-values and thermal conductivity of sapphire fibers Luca Naticchioni, Maurizio Perci, Ettore Majorana (Rome) Measurement of KAGRA radiation shield at cryogenic temperature Kieran Craig (Glasgow) Measurement of coating mechanical dissipation

41. 41 4. Human resources 41 13 visitors supported by ELiTES in the last quater of 2013 Gerd Hofmann, Julius Komma, Ronny Nawrodt (Jena) Cryogenic experiment Silvio Savoia, Massimo Moccia, Adele Fusco, Innovenzo Pinto (Sannio) Cryogenic experiment, Coating Rebecca Douglas, Karen Haughian (Glasgow) Sapphire bonding

42. 42 4. Human resources 42 13 visitors supported by ELiTES in the last quater of 2013 Joris Van Heijningen, Kazuhiro Agatsuma (NIKHEF) Vibration isolation system Gerald Bergmann, Manuela Hanke (Hannover) Cryogenic payload and so on

43. 43 5. Summary KAGRA cryostat Experiment : Initial cooling time of payload Radiation shield vibration Initial cooling time of payload (1) DLC coating reduces initial cooling time as our calculation. (2) Thermal resistance of Cu heat link is a few times lareger than our expectation. Investigation is in progress. Radiation shield vibration We measured. Analysis is in progress.

44. 44 5. Summary Sapphire monolithic suspension Drilled test bulk was delivered on 1st of October. Experiments for sapphire fiber and sapphire bonding are in progress but the results are promising. Thermal conductivity and Q-value of IMPEX fibers are larger than KAGRA reuqirement. We are preparing the first step experiment of monolithic sapphire suspension.

45. 45 5. Summary Human resources Three brilliant fresh persons came from Europe. Strong support from ELiTES In the first three quaters of 2013 : 7 visitors In the last quater of 2013 : 13 visitors

46. 46 Thank you for your attention !

47. 47 6. Human resources 47 Japanese graduate students visited (or will visit) Europe. Yusuke Sakakibara (October 2012 – December 2012) Investigation for coating and sapphire fibers (Glasgow and Jena) ET meeting, Hannover, December 2012 http://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=1420 http://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=1469 (Takanori Sekiguchi (January 2013 – March 2013) Investigation for vibration isolation (Amsterdam) http://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/DocDB/ShowDocument?docid=1708 ) Dan Chen (September 2013 – October 2013) Investigation for sapphire fiber (Rome)

48. 48 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

49. 49 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

50. 50 Construction is in progress (Jecc Torisha). Support frame inside radiation shield

51. 51 8. Summary ELiTES has already started and supports the development of KAGRA cryogenic system. If you want to join our mission, let us know.

52. 52 Cryogenic payload is not a simple system. We need cryostat to test cryogenic payload performance. KAGRA cryostat is not appropriate for test. Cleanness must be kept 1/4 cryostat was delivered in Kashiwa campus. 1/4 means number of cryocooler, not size. It will be delivered on the end of September. 4. 1/4 cryostat

53. 53 Construction is in progress (Jecc Torisha). Vacuum chamber : 1.2 m in diameter, 1.6 m in height 4. 1/4 cryostat

54. 54 Construction is in progress (Jecc Torisha). Radiation shield

55. 55 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

56. 56 Two items for cryoduct (1)300K radiation though this cryo duct must be small. (2)Scattered light noise by this duct should be small. Not only scattered light itself but also vibration of cryo duct should be small. Preparation for experiment is in progress. Yusuke Sakakibara will explain details later. 3. Cryoduct

57. Three of cryostats were move to a warehouse near Kamioka on the 27 th and 28 th of July. 57 2. KAGRA cryostat

58. 58 Test 1 : Initial cooling time The result (2 weeks) is similar to our expectation. There is no large unexpected heat invasion and resistance. 2. KAGRA cryostat Cooling test of KAGRA cryostat in Toshiba

59. 59 Initial cooling test with liquid nitrogen (Jecc Torisha) : 30th Aug. 2013 Delivery : 27th of Sep. 2013 Vacuum chamber : 1.2 m in diameter, 1.6 m in height 3. 1/4 cryostat 1.5hours 100K

60. Three of cryostats were move to a warehouse near Kamioka on the 27 th and 28 th of July. 60 2. KAGRA cryostat

61. 61 Outline of vibration isolation and cryostat 61 2 Pulse tube cryocoolers Pulse tube cryocoolers Baffles Cryoduct Outer shield (80K) Inner shield (8K) Vacuum chamber (300K)

62. Three cryostats were move to a warehouse near Kamioka on the 27 th and 28 th of July. 62 2. KAGRA cryostat

63. 63 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 …

64. 64 Test 2 : Heat load test How much is temperature with extra heat load ? We can derive extra heat load from temperature. Examples for extra heat load Scattered light by mirror Heat absorption in mirror 300 K radiation through holes for main beam 64 Cooling test in Toshiba

65. 65 Cooling test in Toshiba 65 Test 2 : Heat load test 65 Pulse tube cryocoolers Heater and thermometer Sapphire mirror

66. 66 Cooling test of KAGRA cryostat in Toshiba 66 Test 1 : Initial cooling time of ratidation shield How long does it take to cool shield ? Test 2 : Heat load test How much is temperature with extra heat load? C. Tokoku et al., Proceedings of CEC/ICMC 2013 (2EPoE1-03) K. Yamamoto et al., Opening a new era for the astrophysics: The future detectors of gravitational waves (19 April 2013) http://gwdoc.icrr.u-tokyo.ac.jp/cgi- bin/DocDB/ShowDocument?docid=1615 2. KAGRA cryostat

67. Cooling test in Toshiba 67 Test 2 : Heat load test 67 2 W 5 W 10 W 0 W Scatted power is 5 W when scattered loss on the mirror surface is 10 ppm.

68. Cooling test in Toshiba 68 Test 2 : Heat load test 68 Pulse tube cryocoolers Heater and thermometer Sapphire mirror

69. Cooling test in Toshiba 69 Test 2 : Heat load test 69 4 W 10 W 0 W According to our design, temperature should be below 8 K when heat absorption in mirror is 1 W.

70. 70 2. 1/4 cryostat Bid (for parts of 1/4 cryostat) was opened ! (Jecc Torisha) Discussion for final design is in progress. Preliminary and not latest version.

71. 71 Cryogenic mirror Cryostat Vibration Isolation Outline of vibration isolation and cryostat 1. Introduction 14 m

72. 72 After Yusuke left …. Clamp for IMPEX fibers in Jena 4. Sapphire fibers

73. 73 Profile measurement in Glasgow 4. Sapphire fibers

74. 74 Q measurement in Jena 5. Sapphire suspension Sapphire fibers with nail heads

75. 75 Thermal conductivity measurement in Jena 5. Sapphire suspension Sapphire fibers with nail heads

76. 76 Latest summary 5. Sapphire suspension Crystal axis Ribbon ? Sapphire fibers with nail heads