1. Cryogenic sub group 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

2. Contribution
R. TakahashiA, 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. AkutsuA, H. IshizakiA, F. E. Peña ArellanoA, T. SuzukiB, T. TomaruB,
N. KimuraB, S. KoikeB, T. KumeB, ToyodaB, MurakamiB, TerashimaB, HagiwaraB, K. TsubonoC, Y. AsoC, T. UshibaC, K. ShibataC, D. ChenD,
N. OhmaeE, K. SomiyaF, R. DeSalvoG, E. MajoranaH, L. NaticchioniH,
W. JohnsonI, A. CummingJ, R. DouglasJ, K. HaughianJ,
I. MartinJ, P. MurrayJ, G. HammondJ, S. RowanJ , G. HofmannK,
C. SchwarzK, D. HeinertK, R. NawrodtK, S. GotoL, M. TanakaL, S. IokaM,
K. NakamotoM, H. NezukaM, 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 GlasgowJ, Friedrich-Schiller-Universitaet JenaK, Jecc TorishaL,
Toshiba Keihin Product OperationsM, KAGRA collaboration

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. Contents
Introduction
Cryostat
Payload
Human resources
Summary

5. 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, Cryocooler unit, Cryostat, Cryogenic payload 5 5 5 5

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

7. 1. Introduction Outline of vibration isolation and cryostat 14 m
Cryogenic mirror 7

8. 1. Introduction Outline of cryostat Cryogenic payload Mirror S. Koike
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

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

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

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

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

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

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

15. 3. Payload 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). 15 15 15 15 15

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

17. 3. Payload 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) 17 17 17 17 17

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

19. 3. Payload 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. 19 19 19 19 19

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

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

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

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

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

25. 3. Payload 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. 25 25 25 25 25

26. 3. Payload 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. 26 26 26 26 26

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

28. 4. Human resources 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. 28 28 28 28 28

29. 4. Human resources 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 29 29 29 29 29

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

31. 5. Summary Cryostat Cryo duct Payload
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. 5. Summary Payload Fresh persons 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. Thank you for your attention !

34. Sapphire suspension
Q of square nail head 34 34 34 34 34

35. One fiber prototype 35 35 35 35 35

36. 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
The next topic is the vibration of shield. Takanori Sekiguchi calculated the vibration via heat links. Takanori assumed that vibration of heat link anchor in the radiation shield is the same as that of CLIO. But, this vibration depends on the structure of shield. So, Luca from Rome and Chen Dan will measure vibration of radiation shield of KAGRA cryostat on this autumn. Luca and Chen will measure the vertical and horizontal motion. Here, I would like to introduce Chen Dan’s activity for horizontal motion. 36

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
This is the summary. Design and discussion for ¼ cryostat is in progress. Sapphire fibers with nail head can be provided by Moltech and IMPEX. These R&D items are investigated. Other ideas for mirror suspension were proposed. Collaboration with ELiTES in progress and I hope the collaboration with university of Toyama will established near future.

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
This is the issues for development of cryogenic payload; how to assemble and install, strength, control and damping system to reduce fluctuation and instability, cooling and noise.

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 …
This is the issues for development of cryogenic payload; how to assemble and install, strength, control and damping system to reduce fluctuation and instability, cooling and noise.

40. 4. Sapphire fibers After Yusuke left …. Clamp for IMPEX fibers in Jena
Ok, we must check the quality of these fibers. Now, Takafumi Ushiba and Kazunori Shibata proceed with measurement of thermal conductivity and Q-values of sapphire fibers, respectively.

41. 4. Sapphire fibers Profile measurement in Glasgow
Ok, we must check the quality of these fibers. Now, Takafumi Ushiba and Kazunori Shibata proceed with measurement of thermal conductivity and Q-values of sapphire fibers, respectively.

42. 5. Sapphire suspension Sapphire fibers with nail heads
Q measurement in Jena
Ok, we must check the quality of these fibers. Now, Takafumi Ushiba and Kazunori Shibata proceed with measurement of thermal conductivity and Q-values of sapphire fibers, respectively.

43. Outline of vibration isolation and cryostat
Vacuum chamber
(300K)
Inner shield
(8K)
Outer shield
(80K)
Pulse tube cryocoolers
2 Pulse tube cryocoolers
OK, what is cryogenic payload ? This is the cross section of tunnel of LCGT. This tall tower is vibration isolation system. There is cryogenic payload under this vibration isolation. Cryogenic payload is in cryostat. Payload includes mirror, which is the most important part of gravitational wave detector.
2 Pulse tube cryocoolers
Baffles Cryoduct 43 43 43 43 43 43

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

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