11111 K. Yamamoto, R. Takahashi A, H. Tanaka, T. Miyamoto, K. Ono, T. Sekiguchi, Y. Sakakibara, M. Kamiizumi, E. Hirose, A. Khalaidovski, R. Kumar, T. Uchiyama, S. Miyoki, T. Akutsu A, H. Ishizaki A, T. Suzuki B, N. Kimura B, T. Tomaru B, S. Koike B, Y. Aso A, T. Ushiba C, D. Chen D, K. Somiya E, R. DeSalvo F, E. Majorana G, L. Naticchioni G, W. Johnson H, A. Cumming I, R. Douglas I, K. Haughian I, I. Martin I, P. Murray I, G. Hammond I, S. Rowan I, G. Hofmann J, C. Schwarz J, D. Heinert J, R. Nawrodt J, KAGRA collaboration ICRR.UT, NAOJ A, KEK B, Phys.S.UT C, Astro.S.UT D, S.TIT E, Sannio Univ. F, INFN G, Louisiana State Univ. H, University of Glasgow I, Friedrich-Schiller-Universitaet Jena J Development of cryogenic payload for KAGRA V 2014 September 20 The meeting of Physical Society of campus, Saga University, Saga, Saga

2 0. Abstract Although there are many topics, here, I will explain (1)Cryostat (2)Monolithic sapphire suspension

3 Contents 1.Introduction 2.Cryostat 3.Sapphire suspension 4.Summary

44 1. Introduction 444 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)

55 Outline of vibration isolation and cryostat 1. Introduction 14 m

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

7 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

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

Pulse tube cryocoolers Pulse tube cryocoolers Baffles Radiation shield Cryo duct 1. Introduction

10 2. Cryostat 10 One year ago, the cryostats were moved to the warehouse near Kamioka. 10

11 2. Cryostat 11 In this August, the first cryostat was installed at Y end ! 11 Y arm X arm Y end New Atotsu

12 2. Cryostat 12 Cryostat in warehouse 12

13 2. Cryostat 13 In front of the warehouse …. 13

14 2. Cryostat 14 In front of warehouse … 14

15 2. Cryostat 15 Mission on the midnight … 15

16 2. Cryostat 16 Cart in front of entrance of KAGRA site 16

17 2. Cryostat 17 Cryostat on the cart at KAGRA site entrance ! 17

18 2. Cryostat 18 In tunnel 18

19 2. Cryostat 19 In tunnel … 19

20 2. Cryostat 20 Y end 20

21 2. Cryostat 21 Y end 21

22 2. Cryostat 22 Y end 22

23 2. Cryostat 23 In this October, the second cryostat will be installed at X end ! 23 Y arm X arm Y end New Atotsu X end

24 2 Pulse tube cryocoolers Pulse tube cryocoolers Baffles Radiation shield Y. Sakakibara talk Cryo duct 2. Cryostat

25 Y. Sakakibara talk (Measurement of radiation through duct, evaluation of scattered light noise) Baffle Duct Baffle Cryostat Mirror Scattered light 2. Cryostat Cryo duct

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

27 3. Sapphire suspension D. Chen talk Hydroxide Catalysis Bonding

28 Current status 1.R&D for components (fiber, bonding technique …) Strength, thermal resistance, mechanical loss … Largest concern : Mechanical loss, especially, Hydroxide Catalysis Bonding We will measure soon ! 2. Prototype One fiber prototype Full size prototype 3. Sapphire suspension

29 Strength test of sapphire fibers with nail heads in Glasgow (G. Hammond, E. Majorana) Fiber suspended weight. Moreover, weight was swung or pulled. 15kg test hang Broken jointed end 3. Sapphire suspension

30 Strength test of sapphire fibers with nail heads in Glasgow (G. Hammond, E. Majorana) Fiber suspend weight. Moreover, weight was swung or pulled. G. Hammond reported in ELiTES meeting (December 2013). Safety factor derived from measurement : Broken jointed end 3. Sapphire suspension

31 HCB shear strength test at cryogenic temperature (Strength vs crystal direction) Rebecca Douglas and Karen Haughian Preliminary 3. Sapphire suspension Requirement : 1 MPa

32 3. Sapphire suspension Strength of HCB after thermal cycle (D. Chen)

33 3. Sapphire suspension Strength of HCB after thermal cycle (D. Chen)

Thermal resistance 3. Sapphire suspension 34 Paper about thermal conductivity measurement sapphire fibers with nail heads was accepted ! Thermal conductivity is enough high for KAGRA.

3. Sapphire suspension 35 Thermal resistance (HCB and indium bonding, D. Chen) Preliminary Further investigation is necessary, but, this result does not look bad …

3. Sapphire suspension 36 Mechanical dissipation Long fiber, reproducibility … Sapphire fiber with nail head (D. Chen, E. Majorana) Rome

3. Sapphire suspension 37 Mechanical loss of HCB will be measured soon. Mechanical dissipation Mechanical loss of indium (Jena) : D. Chen talk

3. Sapphire suspension 38 Thermal noise calculation (D. Chen, R. Kumar) Mechanical loss of indium looks enough small. Mechanical dissipation

3. Sapphire suspension 39 One fiber prototype (Shorter cooling time, for smaller risk of full size prototype) Assembly : October (D. Chen, H. Tanaka)

3. Sapphire suspension 40 Full size prototype Preparation for (similar size) prototype of lop-eared is in progress.

41 Cleaning up of cooled sapphire mirror 3. Sapphire suspension Cooled sapphire mirror is contaminated (gas). Warming up in short time is necessary.

42 T. Tomaru talk 3. Sapphire suspension Warming up by CO 2 laser

43 Acknowledgement 43 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 Feb. 2016) European people can visit Japan for KAGRA.

44 7. Summary Cryostat The first (second) cryostats was (will be) installed at Y (X) - end of KAGRA site on August (October). Cryo duct Heat transmittance and scattered light noise (Y. Sakakibara talk)

45 7. Summary Sapphire lop-eared monolithic suspension (D. Chen talk) R&D for components Concern : Mechanical loss, especially, Hydroxide Catalysis Bonding. We will measure soon ! Prototype (one fiber, full size) Preparation is in progress. Cleaning up of contaminated cooled sapphire mirror Warming up by CO 2 laser in short time (T. Tomaru talk)

46 Thank you for your attention !

47 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 3. Sapphire suspension

48 Latest summary of Q and thermal conductivity Moltech IMPEX KAGRA requirement Q-value *10 6 5*10 6 at 20K -6*10 6 Thermal Conductivity at 20K [W/m/K] Sapphire fibers with nail heads IMPEX fibers satisfy the KAGRA requirement. 3. Sapphire suspension

49 Bonding between sapphire fibers and sapphire mirror Diffusion bonding Hydroxide Catalysis Bonding (AdLIGO and Virgo) If fibers are broken, bonding parts must be taken apart … Candidates : Indium, Optical contact, Screws Test (in progress or near future plan) Strength test (tensile and shear) : KEK Thermal resistance : ICRR Mechanical dissipation : Jena and Glasgow (ELiTES) 3. Sapphire suspension

50 Bonding between sapphire fibers and sapphire mirror Hydroxide Catalysis Bonding 3. Sapphire suspension Rebecca reported in ELiTES meeting (Dec. 2013).

51 Bonding between sapphire fibers and sapphire mirror Hydroxide Catalysis Bonding (Rebecca Douglas[Glasgow], 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) Rebecca Douglas and Karen Haughian stayed in Japan in the last autumn. Rebecca reported in ELiTES meeting (Dec. 2013) Sapphire suspension

52 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

53 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

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 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 …

56 Metal blade spring for vertical vibration isolation Cryogenic test is in progress in Kashiwa. Q measurement of wires to suspend masses (except for mirror) is in progress (tungsten, CuBe, …) Measurement of magnetism of mass and black coating Control system Cryogenic tests are in progress. Stepping motor to adjust angle of masses : KEK Optical sensor (a candidate to monitor mass motion) : ICRR 5. Other topics

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

58 Profile measurement in Glasgow 4. Sapphire fibers

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