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
ET-meeting, 22th Oct. 2013 N. KIMURA/KEK
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
ET-meeting, 22th Oct. 2013 N. KIMURA/KEK
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
ET-meeting, 22th Oct. 2013 N. KIMURA/KEK
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)
ET-meeting, 22th Oct. 2013 N. KIMURA/KEK
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
ET-meeting, 22th Oct. 2013 N. KIMURA/KEK
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
Pulse tube cryocoolers
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.
ET-meeting, 22th Oct. 2013 N. KIMURA/KEK
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)
ET-meeting, 22th Oct. 2013 N. KIMURA/KEK
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
ET-meeting, 22th Oct. 2013 N. KIMURA/KEK
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
ET-meeting, 22th Oct. 2013 N. KIMURA/KEK
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.
ET-meeting, 22th Oct. 2013 N. KIMURA/KEK
Structure view of the Production Duct Shield
80 K Duct Shield
Bellows
Vacuum VesselSupport Frame
5 m
Baffles
ET-meeting, 22th Oct. 2013 N. KIMURA/KEK
SummarySummary
17
1. KAGRA cryogenics consisting of cryostat and cryo- cooler 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.