et-meeting, 22 th oct. 2013 n. kimura/kek the latest status of the kagra cryogenics n. kimura a, d....

ET-meeting, 22th Oct. 2013 N. KIMURA/KEK

The Latest The Latest Status of the KAGRA CryogenicsStatus of the KAGRA Cryogenics

N. KIMURA A, D. CHEN B, T. KUME A, S. KOIKE A,

Y. SAKAKIBARA B, T. SUZUKI A, C. TOKOKU B,

K. YAMAMOTO B, M. OHASHI B, and K. KURODA B

A High Energy Accelerator Research Organization, KEKB ICRR, University of Tokyo,

ET-meeting, 22th Oct. 2013 N. KIMURA/KEK2

Outline

Over View of KAGRA Cryogenics

Actual Work Schedule

Performance Tests

• Cryostat

• 1/2 Dummy Payload

• Prototype Duct Shield

( Preliminary tests )

Summary


Gate valve Gate valve

Connection Port to SASMirror a cryostat

Location of Four Mirror Cryostats in Kamioka MineConstructed at the position of 1 km in depth.

Mozumi-End Atotsu-End

X-Front RoomY-Front Room

L=5 m

L=5 m

Vacuum duct800 with radiation shield

Vacuum duct800 with radiation shield


Conceptual Design Conceptual Design of the Cryogenicsof the Cryogenics

Four 4K cryocooler units per one cryostat Baffles against wide scattering is cooled via 8K shield.

Main Beam

Cooling 8K shield

Cooling Cryo-Payload

Duct Shield

400kW4W?

~1W

Cryostat80K shield

8K shield

two units

80K PTC withVibration reduction

4K PTC withVibration reduction

two units

2 units for cool cryo-payload2 units cool for 8K shield4 units cool for 80K shield

Low vibration in U. H. VacuumStop propagation of 300K radiationPrevent heating by scattered beam

300K Radiation

Baffles


Overview of KAGRA Overview of KAGRA CryogenicsCryogenics

S.Koike

5 m Duct Shield

Main Laser Beam

Four Cryocooler Units

Radiation Shields

Seismic Attenuation System (SAS)

Cryogenic Payload

Sapphire Mirror(-alumina crystal)

5 m Duct Shield

Stainless steel t=20mmDiameter 2.4 mHeight ~4.3 mM ~ 11 tonCold Mass:8K shield ~455 kg80 K shield ~590 kg

CryocoolersPulse tube, 60Hz0.9 W at 4K (2nd)36 W at 50K (1st)


Actual Work Schedule of KAGRA CryogenicsActual Work Schedule of KAGRA Cryogenics

Manufacture components

Assemble and factory test with cryo-coolers

Transport to storage near Kamioka

2011 Jfy 2012 Jfy 2013 Jfy

Apr./’12 Apr./’13 Apr./’14Apr./’11.

Design by KEK

Bidding

We are here22th/Oct.

Four Mirror Cryostats

Cryo-cooler units

Design by KEK

Production of seven cryo-cooler units with performance test

Production of nine cryo-cooler units with performance test

Transport to Kamioka

Custody at Kamioka

Duct shield units

Design by KEKProduction of three ducts shield units without cryo-coolers

Performance test


Performance of the CryostatPerformance of the Cryostat

• It took 12.5 days to cool down from 300 K to 8K.• Cool down time of the cryostat was almost consistent

with the predicted cooing time by Calculation model.

Performance test at Toshiba Keihin Product

80K Shield Est. (W) Meas. (W) ◦ Eleven View Ports (22) -◦ Radiation From 300 K 70 -◦ Support post and Rods 24 -◦ Electrical wires 3 x 10-4 -

Total 94 (116) 125W/unit 24 (29) 31

8K Shield Esti. (W) Meas. (W) ◦View Ports (0.4)* -◦Radiation From 80 K 2.2 -◦Support post and Rods 2.4 -◦Electrical wires 3 x 10-4 -

◦Duct Shields ( < 0.05 ?) -Total 4.6 (5.0 ?) <2.0

W/unit 2.3 (2.5 ?) <1.0

Cryo-payload Esti. (W) Meas. (W) ◦ Payload (~1.0?) -◦ Mirror Adsorption (~1.0?) -

Total (2.0 ?) -W/unit (1.0 ?)

0.4

8

Heat load Test

88888

Pulse tube cryocoolers



Heater and thermometer

Sapphire mirror

Cooling test in Toshiba

99999

4 W

10 W

0 W

According to our design, temperature should be below 8 K when heat absorption in mirror is 1 W.

Result of Heat Load Response @ Cryo-payload line

Cooling test in Toshiba

It is confirmed that 2.5 ppm (1 W) @400 kW of mirror deposition is acceptable as heat load for the cryocoolers connected with cryo-payload line.


Results (with copper heat links)Results (with copper heat links)• Cryo-coolers for payloads didn’t cool down completely (2nd stage

stayed at 20 K)• Thermal conductivity of heat links calculated from results: 1/5 of

literature– Thermal contact resistance between payloads and heat links

1010

2013.9.22 日本物理学会 2013 年秋季大会

榊原裕介　 Yusuke Sakakibara

EmissivitySapphire: 0.5Platform: 0.3*(T/300K)IM: 0.4*(T/300K)


Measurement of thermal Measurement of thermal radiationradiation

Two aluminum plates suspended1. 600 mm plate (Left side) is heated up to 300 K and emits thermal

radiation2. 250 mm plate (Right side) absorbs radiation and is heated up3. Calibration is conducted using heater on 250 mm plate4. Coated with Solblack to enhance emissivity or absorptivity

Done by Y. Sakakibara

1.11

1. Thermal Radiation

1. 600 mm1. 250 mm

1. 150 K 1. 250 K 1. 40 K

1. 17 m

Performance Test of the Prototype Duct ShieldPerformance Test of the Prototype Duct Shield


ResultsResults

Calculated value has error of several times◦ Measured reflectivity at 10 μm of shield has error◦ Rays are reflected by shield many times

Measured value is within the error12

Reflectivity at 10 umDuct 0.94±0.02Solblack 0.7±0.1

Reduced

by Duct Shield


Measurement of scattered Measurement of scattered lightlight

Red light from laser diode◦ Photographs of

scattered light when angle changes

◦ Calibration by changing exposure time

◦ Future work: Vibration measurement, calculation of equivalent GW amplitude

Yusuke Sakakibara 13

~200 ppm of laser light came back to

camera

635 nm, 4.5 mW

Background

5 ｍ

Fixed points

Modal analysis for KAGRA Duct Shield

Φ800

Gravitational Direction

We analyzed the resonance peaks of the vacuum chamber without bellows and the inner shield.Mode frequency are calculated from 20 Hz to 100 Hz.

F17 77.16 Hz F18 94.00 Hz

F19 96.18 Hz F20 99.86 Hz

Resonant FrequencyF1 18.85 Hz F2 25.48 Hz F3 38.52 Hz F4 40.28 Hz F5 40.99 Hz F6 43.65 Hz F7 44.20 Hz F8 46.31 Hz F9 49.01 Hz F10 59.07 Hz F11 63.66 Hz F12 64.58 Hz F13 68.25 Hz F14 68.69 Hz F15 73.87 Hz F16 77.00 Hz F17 77.16 Hz F18 94.00 Hz F19 96.18 Hz F20 99.86 Hz

Shape of duct shield at each resonant frequency.

It was confirmed that the most of resonant frequencies are cause of strength of the vacuum chamber, and weaker than that of inner shield.These results have been feedback to the duct shield design.


Structure view of the Production Duct Shield

80 K Duct Shield

Bellows

Vacuum VesselSupport Frame

5 m

Baffles


SummarySummary

17

1. KAGRA cryogenics consisting of cryostat and cryocooler units was designed, fabricated, and tested their performances during 2011JFY and 2012JFY.2. At the performance test, following items were confirmed and verified;

• The cooling and vibration performance of sixteen cryocooler units.

• The cooling performance of all the four cryostats.• Vibration on the surface of inner radiation shield.• Experiment with half size of dummy cryo-payload

3. Experiment with proto type duct shield was conducted, and result was agreed with predicted heat load. But, need more analysis work.4. Design of the production of duct shield were almost finished. Now, We are focusing our work on fabrication of the duct shields and preparing performance test.

et-meeting, 22 th oct. 2013 n. kimura/kek the latest status of the kagra cryogenics n. kimura a, d....

Documents

radiation shield slide

shield esti

shield low vibration

w cryostat

kimurakek performance

duct shield main laser

duct shield stainless

cool cryopayload