1. Status of KAGRA Cryogenics III
Installation and cooling of cryogenic mirror payload on KAGRA site
Kazuhiro Yamamoto, Yuki InoueAB, Ayako UedaA,
Takafumi UshibaC,Toshiro OchiC, Nobuhiro KimuraA, Rahul KumarA, Toshikazu SuzukiC, Suguru TakadaD, Hiroki TanakaC, Shinichi TerashimaA,
Takayuki TomaruA, Yoshikazu NamaiA, Ayako HagiwaraA,
Kunihiko HasegawaC, Masashi FukunagaC, Helios VoccaE,
Takahiro MiyamotoC, Isao MurakamiA, Tomohiro YamadaC,
Takaharu ShishidoA, Toshiya Yoshioka,Takashi UchiyamaC, Takaaki KajitaC, Shinji MiyokiC
Department of Physics University of Toyama, AKEK, BAcademia Sinica, CICRR, DNIFS, EINFN Perugia
2018 March 22
The meeting of Physical Society of Japan
@Noda campus, Tokyo University of Science, Noda, Chiba 1 1 1 1

2. KAGRA Cryogenics subGroup
Members in Japan
Takayuki TOMARU
Chief
KEK, Assoc. Prof.
Nobuhiro KIMURA
Cryostat sub-chief
KEK, Assoc. Prof.
Kazuhiro YAMAMOTO
Sapphire sub-chief
UToyama, Assoc. Prof.
Takafumi USHIBA
Cryo-Payload sub-chief
ICRR, PD
Toshikazu SUZUKI
Cryostat, Payload
KEK, Prof.
Rahul KUMAR
Simulation, Payload
KEK, PD
Suguru TAKADA
Cryogenics
NIFS, Assist. Prof.
Members from Taiwan
Members in Italy
Helios VOCCA
HCB, Perugia U,
Assist. Prof.
Yuki INOUE
Cryogenic Payload
AS, PD

3. Technicians No Photo Shinichi TERASHIMA Yoshikazu. NAMAI Ayako UEDA
Machining
KEK, Technical Staff
Yoshikazu. NAMAI
Welding, KEK
Technical Staff
Ayako UEDA
Exp. Assistant, KEK
Technical Staff
Ayako HAGIWARA
CAD
KEK, Technical Staff
No Photo
Isao MURAKAMI
Machining
KEK, Technical Staff

4. Students Hiroki TANAKA Takahiro MIYAMOTO Kunihiko HASEGAWA
Cryo-Payload, Q
ICRR, D2
Takahiro MIYAMOTO
Cryo-Payload
ICRR, D2
Kunihiko HASEGAWA
Cryo-Payload
ICRR, D1
Tomohiro YAMADA
Cryo-Payload
ICRR, M2
Toshiro OCHI
Cryo-Payload
ICRR, M2
Masashi FUKUNAGA
Cryo-Payload
ICRR, M1
Takaharu SHISHIDO
Cryo-Payload
KEK, M1

5. 0. Abstract Here, I explain (1) Progress and future plan at KAGRA site
(2) Investigation items
in cryogenic payload
(Details are presented in this session) 5

6. Items in cryogenic payload Future plan Summary
Contents
Introduction
Progress at site
Items in cryogenic payload
Future plan
Summary 6

7. 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 (Type A), Cryocooler unit, Cryostat, Cryogenic payload 7 7 7 7 7 7 7 7

8. Vibration isolation system Vacuum ducts along laser beam
1. Introduction
Outline of vibration isolation and cryostat
Design drawing with tunnel and cross section
2nd floor
A. Hagiwara
Vibration isolation system
(room temperature)
14 m
K. Okutomi
22pK402 4
Shaft
Clean booth
Vacuum ducts along laser beam
Cryostat
(Here the mirror is) 8 8 8

9. 1. Introduction Schematic view of cryo-payload Heat link Sapphire
mirror

10. 1. Introduction Connection between mirror and fibers is crucial point.
Schematic view of sapphire suspension
Connection between mirror and fibers is crucial point.
KAGRA adopts sapphire ears for this connection.
Connection between mirror and ears must be strong.
Hydroxide Catalysis Bonding (HCB) is adopted. This bonding is based on chemical reaction.
Sapphire
fibers
Sapphire
mirror 10 10 10 10 10 10 10 10 10 10 10

11. 1. Introduction Connection between mirror and fibers is crucial point.
Schematic view of sapphire suspension
Connection between mirror and fibers is crucial point.
KAGRA adopts sapphire ears for this connection.
Connection between mirror and ears must be strong.
Hydroxide Catalysis Bonding (HCB) is adopted. This bonding is based on chemical reaction.
Sapphire
fibers
Sapphire
mirror 11 11 11 11 11 11 11 11 11 11 11

12. 1. Introduction Sapphire mirror 22cm 15cm 23kg
（Density is 4 times larger than that of water） 12 12 12 12 12 12 12 12

13. 2. Progress at site
2018 spring：Test run of cryogenic simple Michelson interferometer(with 2 sapphire mirrors）
Y end
Extra mirror
It is cooled down !
ETM
X end Installation of practical mirror is in progress.
3km MC
PRM
ETM BS IO
3km 13 13 13 13 13 13 13 13 13 13 13

14. 2. Progress at site
Cryogenic payload with extra sapphire mirror was installed (suspended by Type A at Y end) at end of November 2017.

15. 2. Progress at site
Cryogenic payload with extra sapphire mirror was installed (suspended by Type A at Y end) at end of November 2017.

16. 2. Progress at site
This cryogenic payload (at Y end) was cooled down at middle of March 2017.
7th of February
14th of March

17. 2. Progress at site
Direction of this cooled sapphire mirror (at Y end) was adjusted. Reflected light arrives at photo detector.
ETM IO MC BS
PRM
3km
Light reflected by ETM arrives !

18. 2. Progress at site
Resonances of cryogenic payload of this cooled sapphire mirror (at Y end) should be suppressed (damping).
Yaw motion sapphire mirror
is most serious problem.
Amplitude of yaw motion : 10 mrad
Requirement : 1 mrad
Yaw motion

19. 2. Progress at site HCB for ears in clean room at University of Toyama
September and October 2017
Two extra mirrors
-> One of them was installed
at Y end.
January 2018
First practical mirror !
-> Installation is being in progress
at X end.
HCB for ears

20. 2. Progress at site

21. 2. Progress at site
First practical sapphire mirror was transported to KAGRA site on 9th of March 2018.
On 8th of March, this mirror in clean room in University of Toyama was shown to mass media.
Almost all main newspapers and televisions came.
Sapphire mirror

22. 3. Items in cryogenic payload
Schematic view of cryo-payload
Sapphire
mirror is contaminated by residual gas.
Power recycling to reduce shot noise (quantum fluctuation of phase of laser) could not effective.

23. 3. Items in cryogenic payload
Change of power recycling gain in 1 year operation
K. Hasegawa 22pK402 8

24. 3. Items in cryogenic payload
Schematic view of cryo-payload

25. 3. Items in cryogenic payload
Outline of cryogenic payload
Platform
Sensor and actuator (for control and damping)
Marionette
Intermediate mass
Sapphire Mirror 25 25 25 25 25 25 25

26. 3. Items in cryogenic payload
Outline of cryogenic payload
Platform
Coil magnet actuator
Fluctuation of magnetic fields can shake mirrors.
Marionette
Intermediate mass
Sapphire Mirror
Coils
Magnets 26 26 26 26 26 26 26

27. 3. Items in cryogenic payload
In order to evaluate magnetic field noise, magnetic moment of magnets are measured.
H. Tanaka
22pK402 9 27 27 27 27 27 27 27

28. 3. Items in cryogenic payload
Outline of cryogenic payload
Relative optical displacement sensor
Efficiency of sensor depends on temperature.
Platform
Marionette
Intermediate mass
Sapphire Mirror 28 28 28 28 28 28 28

29. 3. Items in cryogenic payload
Calibration of optical displacement sensor at low and room temperature
M. Fukunaga
22pK402 10 29 29 29 29 29 29 29

30. 3. Items in cryogenic payload
Schematic view of cryo-payload
Heat link
Heat path to cool down
It also transmits
vibration ! 30

31. 3. Items in cryogenic payload
Measurement of thermal conductivity of heat links
Calculation of vibration transmitted by heat links
T. Yamada
22pK402 11 31

32. 3. Items in cryogenic payload
Schematic view of cryo-payload
Vibration
Vibration can contaminate output of KAGRA detector via
(1)Heat link
(2)Scattered light
Radiation shield 32

33. 3. Items in cryogenic payload
Vibration measurement
T. Ochi
22pK402 12 33

34. 4. Future plan
2018 spring：Test run of cryogenic simple Michelson interferometer(with 2 sapphire mirrors）
ETM
3km MC
PRM
ETM BS IO
3km 34 34 34 34 34 34 34 34 34 34 34 34 34 34 34 34 34 34 34 34 34 34 34

35. 4. Future plan
2018 spring：Test run of cryogenic simple Michelson interferometer(with 2 sapphire mirrors）
Test run : 23 April 2018 –
Measurement items of Cryogenic subgroup
3km Michelson interferometer has highest sensitivity at site.
Michelson interferometer can be calibrated well.
Mechanical response (transfer function) of cryogenic payload
Calibration of local (relative displacement) sensor
Injection test (vibration, magnetic field) 35 35 35 35 35 35 35 35 35 35 35

36. 4. Future plan After test run on spring 2018
Other three practical mirrors will be installed by spring of 2019.
-> Adjustment and so on.
-> Observation with LIGO and Virgo (O3)
ETM
Extra mirror will be replaced with practical one.
Y-arm
ITM MC
PRM
ETM BS
X-arm IO
ITM 36 36 36 36 36 36 36 36 36 36 36

37. 5. Summary Progress at site
One extra mirror was installed and cooled down at Y end.
One practical mirror is being installed at X end.
Future plan at site
On spring of 2018
Test run of cryogenic simple Michelson interferometer
with two sapphire mirrors.
By spring of 2019
All four practical sapphire mirrors will be installed.
Investigation items of cryogenic payload
Details will be presented by next 5 speakers. 37

38. Thank you for your attention !38

39. Backup 39

40. 2. Cryostats at site
We must conduct cooling test of all cryostats by March 2017.
So far, at both ends, missions for assembly and connection were over.
Leak check is current main mission at both ends.
Mission for two cryostats in center room will be started on November.

41. 2. Cryostats at site
So far, at both ends, missions as below were over.
(2) Connection 4K cryocoolers unit to each cryostats
to SAS
Outline of cryostat
4 Low vibration
cryocooler unit
Remote
valve unit
S. Koike 41

42. 3. Cryogenic payload Outline of vibration isolation and cryostat
Pulse tube cryocoolers
Pulse tube cryocoolers
Cryo-payload 42 42 42 42 42 42 42

43. 3. Cryogenic payload Outline of vibration isolation and cryostat
Platform
Recoil mass for Marionette
Recoil mass for intermediate mass
Recoil mass for mirror
A. Hagiwara 43 43

44. 3. Cryogenic payload Outline of cryogenic payload Mirror chain
Platform
Recoil mass chain
Marionette
Intermediate mass
Thermal noise caused by recoil mass chain is small.
Sapphire Mirror 44 44 44 44 44 44 44

45. 3. Cryogenic payload Outline of cryogenic payload GAS filer Platform
for vertical
vibration isolation
(Mirror chain is
suspended)
Platform
Marionette
Intermediate mass
Sapphire Mirror 45 45 45 45 45 45 45

46. 3. Cryogenic payload Outline of cryogenic payload Platform
Alignment adjustment system
Platform
Marionette
Simple system for
high Q-value of sapphire suspension
Intermediate mass
Sapphire Mirror 46 46 46 46 46 46 46

47. 3. Cryogenic payload Outline of cryogenic payload Platform
Sensor and actuator (for control and damping)
Marionette
Intermediate mass
Sapphire Mirror 47 47 47 47 47 47 47

48. 3. Cryogenic payload Sapphire lop-eared suspension
“Sapphire monolithic
lop-eared suspension”
One of the most important
parts of KAGRA :
Main sapphire mirrors
are included.
All parts are made
from sapphire. 48

49. 3. Cryogenic payload Blade spring Fiber with nail head on both ends
Sapphire lop-eared suspension
Blade spring
(compensation of fiber length difference)
Fiber with nail head on both ends
Flat cut
Nail head of fiber
Mirror
Ear
A. Hagiwara

50. 3. Cryogenic payload Sapphire lop-eared suspension
Indium bonding on both nail heads of fiber
When fibers are broken, they can be removed !
Hydroxide Catalysis Bonding
between ear and mirror

51. 3. Cryogenic payload
Current hot topics (presentations in this session)
R. Kumar’s talk 51 51 51 51 51 51 51 51

52. 3. Cryogenic payload
Current hot topics (presentations in this session)
Assembly sapphire suspension
(Bonding between ears and mirror)
K. Craig’s talk
(K. Yamamoto presents on behalf of him) 52 52 52 52 52 52 52 52

53. 53

54. 3. Cryogenic payload Outline of cryostat Cryogenic payload Mirror
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

55. 3. Cryogenic payload Outline of vibration isolation and cryostat
Heat link (pure Al)
Heat link (pure Al)
Pulse tube cryocoolers
Pulse tube cryocoolers
Cryo-payload 55 55 55 55 55 55 55

56. 3. Cryogenic payload Design A. Hagiwara proceeds with
Without recoil chain
Design
A. Hagiwara proceeds with
CAD design drawings. Almost
all parts except for platform
were designed.
Design is based
on discussion
with Vibration Isolation
subgroup of KAGRA.
Marionette
Platform
Intermediate mass
Mirror
A. Hagiwara 56 56

57. 3. Cryogenic payload Prototype test of cryogenic payload
Two differences from actual one
Platform does NOT include
GAS filter.
Mirror and fibers are NOT made from sapphire, but metal. 57

58. 3. Cryogenic payload Prototype test of cryogenic payload
Without recoil chain
Prototype test of cryogenic payload
Marionette, Intermediate mass,
Dummy mirror, Recoil mass
For (dummy mirror) has already
been delivered.
Marionette
Intermediate mass
Dummy Mirror (and recoil mass)
A. Hagiwara 58 58

59. 2. Sapphire suspension
All sapphire parts for full size prototype have already been delivered (IMPEX and Shinkosha).
Sapphire cylinder with flat cuts
as dummy mirror
Fibers with nail head
Blade spring
Ears 59 59 59 59 59 59 59 59

60. 1. Introduction Schematic view of cryo-payload Sapphire suspension
Pulse tube cryocoolers
Pulse tube cryocoolers
Sapphire fiber
Cryo-payload
Sapphire mirror (About 20K)

61. 1. Introduction Schematic view of cryo-payload Sapphire suspension
Pulse tube cryocoolers
Pulse tube cryocoolers
Cryo duct