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K. Yamamoto, R. Takahashi, T. Sekiguchi, Y. Sakakibara, C. Tokoku, M. Kamiizumi, U. Iwasaki, E. Hirose, T. Uchiyama, S. Miyoki, M. Ohashi, T. AkutsuA, H. IshizakiA, T. SuzukiB, N. KimuraB, S. KoikeB, 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, S. RowanJ , G. HofmannK, C. SchwarzK, D. HeinertK, R. NawrodtK, 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

Development of cryogenic payload

for KAGRA II

2013 March 26The meeting of Physical Society of Japan

@Hiroshima University, Higashi Hiroshima, Hiroshima

2

0. Abstract

Although there are many topics, but here,I will explain

(1)1/4 cryostat(2)Experiments in Toshiba cooling test(3)Sapphire fibers(4)Mechanical loss of coating

3

Contents1.Introduction2.1/4 cryostat3.Experiments in Toshiba cooling test 4.Sapphire fibers5.Mechanical loss of coating6.Summary

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1. Introduction

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3km3km

MozumiY-end Sakonishi

X-end

AtotsuCenter

Vibration isolation system, Cryocooler unit, Cryostat, Cryogenic payload

Schematic view of KAGRA interferometerFour mirrors of arm cavity will be cooled. T. Suzuki’s talk

Kamioka mine (Underground site)

5

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 cryostatCryogenic

payload

Mirror(20K)

1. Introduction

S. Koike

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Outline of cryogenic payload

Sapphire fiber

Sapphire mirror

(About 20K)

Inner shield(8K)

1. Introduction

Y. Sakakibara et al.,Classical and Quantum Gravity 29 (2012) 205019.

Outer shield(80K)

Heat links(pure Al)

Vacuum chamber

(300K)

7

Cryogenic payload is not a simple system.

We need cryostat to test cryogenic payload performance.

KAGRA cryostat is not appropriate for test.(1)Difficult access in mine(2)Cleanness must be kept

1/4 cryostat will be prepared in Kashiwa campus.1/4 means number of cryocooler, not size.

2. 1/4 cryostat

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2. 1/4 cryostatConstruction of vacuum chamber is in progress. (Jecc Torisha, 1.2 m in diameter, 1.6 m in height)

Cooling test of KAGRA cryostat is in progress. T. Suzuki’s talk

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We have plans of experiments in Toshiba cooling test of KAGRA cryostat.

Experiment 1 : Initial cooling time

Experiment 2 : Measurement of shield vibration

All items were installed ! Cooling is in progress.

3. Experiments in Toshiba cooling test

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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

3. Experiments in Toshiba cooling test

Y. Sakakibara’s talk

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Al hollow spheres (100 mm in diameter)

Y. Sakakibara’s small experiment in Kashiwa : 30 mm in diameterWithout DLC

With DLC

Experiment 1 : Initial cooling time

3. Experiments in Toshiba cooling test

Sphere with DLC (2nd cryostat) Sphere with SolBlack (4th cryostat) Sphere without black coating (1st cryostat)

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Al hollow spheres (100 mm in diameter) Experiment 1 : Initial cooling time

3. Experiments in Toshiba cooling test

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Al hollow spheres (100 mm in diameter) Experiment 1 : Initial cooling time

3. Experiments in Toshiba cooling test

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Dummy payload (hollow masses, 3rd cryostat)

Half sizeHollow masses (~5 kg)DLC coatingSapphire bulk as dummy mirror

S. Koike

(100 mm in diameter)

Evaluation of emissivity

Experiment 1 : Initial cooling time

3. Experiments in Toshiba cooling test

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Experiment 1 : Initial cooling timeDummy payload

3. Experiments in Toshiba cooling test

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Experiment 1 : Initial cooling timeDummy payload

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3. Experiments in Toshiba cooling test

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Experiment 1 : Initial cooling timeDummy payload

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3. Experiments in Toshiba cooling test

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Vibration of shield could be problems. Vibration via heat links, Scattered lightWe 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 (2nd cryostat) and horizontal (3rd cryostat) vibration of radiation shield of KAGRA in cooling test of Toshiba, respectively. Dan Chen’s talk

Experiment 2 : Measurement of shield vibration

3. Experiments in Toshiba cooling test

1919Luca’s accelerometer was installed (13th of Feb).

Experiment 2 : Measurement of shield vibration

3. Experiments in Toshiba cooling test

Maurizio Perciballi

Ettore Majorana also visited in March.

2020

Experiment 2 : Measurement of shield vibration

Luca’s accelerometer was installed in the shield (13th of Feb).

3. Experiments in Toshiba cooling test

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Experiment 2 : Measurement of shield vibration

Dan’s accelerometer was installed in the shield. (8th of Mar).

3. Experiments in Toshiba cooling test

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Experiment 2 : Measurement of shield vibration

Dan’s accelerometer was installed in the shield. (8th of Mar).

3. Experiments in Toshiba cooling test

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4. Sapphire fibers

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Test sample (T. Uchiyama)

Sapphire fibers with nail heads are necessary to suspend mirrors.

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Length = 350 mm diameter = 1.8 mm Almost as needed in bKAGRA.Need to check the quality and improvement .

T. Uchiyama asked MolTech GmbH (Germany).Sapphire fibers have already come !

4. Sapphire fibers

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Ettore Majorana asked IMPEX HighTech GmbH (German company).They made similar fibers (nail heads on the both ends).

4. Sapphire fibers

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Quality check

Q-value Measurement in Glasgow and Jena Y. Sakakibara visited for measurement. Plan for measurement in Rome and ICRR (C. Schwarz and G. Hofman’s visit from Jena) Thermal conductivity Measurement in Jena Plan for measurement in Rome and ICRR

Strength test Discussion with Glasgow (Thanks for E. Hirose)

4. Sapphire fibers

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Q measurement in Jena (cool) and Glasgow (300K)

It is slightly smaller than KAGRA requirement !

Preliminary result

4. Sapphire fibers

Y. Sakakibara

Moltech

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After Y. Sakakibara left ….

It is comparable with KAGRA requirement !

Q measurement in Jena

Preliminary result

4. Sapphire fibers

MoltechC. Schwarz

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After Y. Sakakibara left ….

It is slightly smaller than KAGRA requirement !

Q measurement in Jena

Preliminary result

4. Sapphire fibers

IMPEXR. Douglas’s poster in LVC meeting (March 2013)

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It is same as KAGRA requirement (size effect)

Thermal conductivity measurement in Jena

Preliminary result

4. Sapphire fibers

T. Tomaru et al., Phys. Lett. A 301 (2002) 215.

Moltech

C. Schwarz

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It is smaller than KAGRA requirement, but same order of magnitude.

Preliminary result

4. Sapphire fibersThermal conductivity measurement in Jena

Moltech

C. Schwarz

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4. Sapphire fibersThermal conductivity measurement in Jena

Thermal conductivity of IMPEX fibers will be measured soon.

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5. Mechanical loss of coating

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Discrepancy between Tokyo and Glasgow

Tokyo Glasgow

K. Yamamoto et al., Physical Review D 74 (2006) 022002.

I.W. Martin et al., Classical and Quantum Gravity 27 (2010) 225020.

Some samples of Japanese coating were sent to Glasgow. Y. Sakakibara measured loss of these samples in Glasgow (room temperature). Glasgow group continues the mission for the cryogenic temperature. K. Graig (Glasgow) joins measurement (April).

E. Hirose is measuring mechanical loss of other Japanese samples in ICRR (University of Tokyo).Construction of the measurement system for KAGRA coating

Result is coming soon !

5. Mechanical loss of coating

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CryostatCryocooler

Optical lever

Lock in amp

Experimental apparatus in ICRR

5. Mechanical loss of coating

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Sapphire disk

Inside cryostat

5. Mechanical loss of coating

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5. Summary1/4 cryostat : Construction of vacuum chamber is in progress.

Experiments in Toshiba cooling test : Initial cooling time (Y. Sakakibara’s talk) Metal sphere with and without black coating 1/2 dummy payload Measurement of shield vibration (D. Chen’s talk)

All items were installed ! Cooling is in progress.

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5. SummarySapphire fibers Moltech and IMPEX provided fibers with nail heads. Measurement of Q-values and thermal conductivity : Result is preliminary, but promising. Discussion for strength test was started.

Mechanical loss of coating Measurement is in progress and result is coming soon !

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Acknowledgement

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.

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Thank you for your attention !

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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

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8. SummaryCryostat : Assembly is in progress. Cooling test is coming soon.Cryogenic duct : Optimum position of 5 buffles Future work : scattered lightCryocooler unit : Cooling test and vibration measurement : OKCryogenic 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

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8. Summary

ELiTES has already started and supports the development of KAGRA cryogenic system.

If you want to join our mission, let us know.

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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

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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 …

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Cryogenic mirror

Cryostat

Vibration Isolation

Outline of vibration isolation and cryostat

1. Introduction

14 m

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Initial cooling time with DLC (shield and mass)

Calculation by Y. Sakakibara Almost half !

Experiment 1 : Initial cooling time

3. Experiments in Toshiba cooling test

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Experiment 1 : Initial cooling timeExperimental test of effect of high emissivity coating (DLC)

Inner sphere (copper) is suspended

inside outer sphere (aluminum) at 77 K

Cooling time is examined with and without DLC coating

3. Experiments in Toshiba cooling test

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Experiment 1 : Initial cooling time

We can observe DLC effect.

3. Experiments in Toshiba cooling test

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The sphere without DLC is being cooled now !Latest result

Experiment 1 : Initial cooling time

Calculation of Yusuke is quite correct !

Sample 1 : Metal hollow spheres

3. Experiments in Toshiba cooling test

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Experiment 1 : Initial cooling timeSample 2 : Dummy payload

51515151

Yusuke calculated the cooling time of 1/2 dummy payload.

3. Experiments in Toshiba cooling test

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Dan Chen’s accelerometer

His accelerometer is consistent with commercial one (in air).

Experiment 2 : Measurement of shield vibration

3. Experiments in Toshiba cooling test

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Dan Chen’s accelerometer

He is proceeding with cryogenic test before measurement in Toshiba.

Experiment 2 : Measurement of shield vibration

3. Experiments in Toshiba cooling test

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Luca Naticchioni’s accelerometer

Experiment 2 : Measurement of shield vibration

3. Experiments in Toshiba cooling test

5555Luca’s accelerometer was installed (13th of Feb).

Experiment 2 : Measurement of shield vibration

3. Experiments in Toshiba cooling test

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Profile measurement in Glasgow

4. Sapphire fibers

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After Yusuke left …. Clamp for IMPEX fibers in Jena

4. Sapphire fibers

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2. 1/4 cryostatBid (for parts of 1/4 cryostat) was opened ! (Jecc Torisha) Vacuum chamber has already been made.

Preliminary and

not latest version.