Cryogenic payload for KAGRA Kazuhiro Yamamoto Institute for

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

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. De. Salvo. 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, NAOJA, KEKB, Phys. S. UTC, Astro. S. UTD, E. UTE, S. TITF, Sannio Univ. G, INFNH, Louisiana State Univ. I , University of Glasgow. J, Friedrich-Schiller-Universitaet Jena. K, Jecc Torisha. L, Toshiba Keihin Product Operations. M, KAGRA collaboration 2

0. Abstract Although there are many topics, but here, I will explain (1)Experiments in KAGRA cryostat (2)Monolithic sapphire suspension 3

1. 2. 3. 4. 5. Contents Introduction Experiments in KAGRA cryostat Sapphire suspension Human resources Summary 4

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

1. Introduction Outline of cryostat to SAS Cryogenic payload Cryostat Stainless steel t 20 mm Diameter 2. 6 m Height ~3. 6 m M ~ 10 ton Mirror View ports M N. Kimura’s talk Cryo-coolers Pulse tube, 60 Hz 0. 9 W at 4 K (2 nd) 36 W at 50 K (1 st) 4 Low vibration cryocooler unit ai n LA SE S. Koike R be a Remote valve unit m 6

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

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

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

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

2. Experiments in KAGRA cryostat 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. 11

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

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

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

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

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

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

2. Experiments in KAGRA cryostat 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) ? 18

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

2. Experiments in KAGRA cryostat 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 20

2. Experiments in KAGRA cryostat 1/4 cryostat for perfomance test of cryogenic payload Vacuum chamber : 1. 2 m in diameter, 1. 6 m in height Delivery : 27 th of Sep. 2013 21

2. Experiments in KAGRA cryostat Experiment 2 : Measurement of shield vibration 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. 22

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

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

3. Sapphire suspension 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 25

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

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

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

3. Sapphire suspension Sapphire fibers with nail heads Mol. Tech Gmb. H (Germany) and IMPEX High. Tech Gmb. H (Germany) have already delivered ! Although the size is similar to that of KAGRA, quality check is necessary. 29

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

3. Sapphire suspension Sapphire fibers with nail heads Latest summary Moltech IMPEX Q-value 107 at 20 K Thermal Conductivity 3000 at 20 K [W/m/K] 1*106 - 6*106 5000 -9000 KAGRA requirement 5*106 5000 Although IMPEX fiber satisfies requirement (Details are in D. Chen’s poster), further investigation is necessary (polish of nail head surface …). 31

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

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

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

3. Sapphire suspension Bonding between sapphire fibers and sapphire mirror Investigation of Hydroxide Catalysis Bonding is in progress in Glasgow. (Rebecca Douglas, GWADW 2013). 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). 35

3. Sapphire suspension 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 36 as first step.

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

4. Human resources 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 38

4. Human resources ELi. TES: ET-LCGT interferometric Telescope Exchange of Scientists Grant for collaboration about cryogenic between KAGRA and ET European 7 th Framework Programme Marie Curie action (Mar. 2012 - Feb. 2016) European people can visit Japan for KAGRA. 39

4. Human resources 7 visitors supported by ELi. TES 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 40

4. Human resources 13 visitors supported by ELi. TES 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 41

4. Human resources 13 visitors supported by ELi. TES 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 42

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. 43

5. Summary Sapphire monolithic suspension Drilled test bulk was delivered on 1 st 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. 44

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

Thank you for your attention ! 46

6. Human resources 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/Doc. DB/Show. Document? docid=1420 http: //gwdoc. icrr. u-tokyo. ac. jp/cgi-bin/private/Doc. DB/Show. Document? docid=1469 (Takanori Sekiguchi (January 2013 – March 2013) Investigation for vibration isolation (Amsterdam) http: //gwdoc. icrr. u-tokyo. ac. jp/cgi-bin/Doc. DB/Show. Document? docid=1708 ) Dan Chen (September 2013 – October 2013) Investigation for sapphire fiber (Rome) 47

7. For future 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 48

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 49

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

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

4. 1/4 cryostat 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. 52

4. 1/4 cryostat Construction is in progress (Jecc Torisha). Vacuum chamber : 1. 2 m in diameter, 1. 6 m in height 53

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

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 55

3. Cryoduct Two items for cryoduct (1)300 K 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. 56

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

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

3. 1/4 cryostat Initial cooling test with liquid nitrogen (Jecc Torisha) : 30 th Aug. 2013 Delivery : 27 th of Sep. 2013 Vacuum chamber : 1. 5 hours 100 K 1. 2 m in diameter, 1. 6 m in height 59

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

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

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

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 … 63

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

2. KAGRA cryostat Cooling test of KAGRA cryostat in Toshiba 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 (2 EPo. E 1 -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/cgibin/Doc. DB/Show. Document? docid=1615 66

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

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

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

2. 1/4 cryostat Bid (for parts of 1/4 cryostat) was opened ! (Jecc Torisha) Discussion for final design is in progress. d n a y. r n a o n i i s r m i e l Pre atest v l t o n 70

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

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

4. Sapphire fibers Profile measurement in Glasgow 73

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

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

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