Transcript Present Design of LCGT Cryogenics Payload

The Latest Status 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
High Energy Accelerator Research Organization, KEK
B ICRR, University of Tokyo,
A
ET-meeting, 22th Oct. 2013 N. KIMURA/KEK
Outline
 Over View of KAGRA Cryogenics
 Time Line
 Performance Tests
Cryostat with Cryocooler-units
• 1/2 Dummy Payload
• Vibration in the cryostat
•
( Mr. D. Chen presented at poster session)
•
Prototype Duct Shield
( Preliminary results )
 Summary
ET-meeting, 22th Oct. 2013 N. KIMURA/KEK
2
Overview of KAGRA Cryogenics
Stainless steel t=20mm
Diameter 2.4 m
Height ~4.3 m
Radiation Shields
M ~ 11 ton
Cold Mass:
8K shield ~455 kg
80 K shield ~590 kg
Four Cryocooler Units
ET-meeting, 22th Oct. 2013 N. KIMURA/KEK
Seismic Attenuation System (SAS)
Cryogenic Payload
Sapphire Mirror
(-alumina crystal)
Cryocoolers
Pulse tube, 60Hz
0.9 W at 4KS.Koike
(2nd)
36 W at 50K (1st)
Meets the requirements for the KAGRA Cryogenics
The requirements for KAGRA Cryogenic
• Adopt Pulse Tube-type Cryo-cooler units
with• very
low vibration
mount
on the CLIO
type.
Temperature
of the
testbased
mass/mirror
< 23 [K]
• Adopt conduction cooling technique with high pure metal
Inner radiation shield have to be cooled to < 8 [K]
such as 6N class Aluminum.
• The test mass have to be cooled without introducing
No use cryogenic fluid cause of vibration noise such as
excessflow.
noise, especially vibration due to cryocoolers.
liquid helium
• Easy the
access
and enough
capacity
• Analyzed
cryostat
response
to ground motion
@ Kamioka-mine.
to installation work around the mirror.
• Heat
load fromsize
components
aspossible
low as possible.
• Allowable
as large as
under public
• Adopt very low outgas super insulation system for
transport regulation and KAGRA tunnel.
under ultra high vacuum < 10-7 [Pa],
• Meets ultra high vacuum specification < 10-7 [Pa]
and polish by Electrical Chemical Baffling
for inner surface of the vacuum chambers.
ET-meeting, 22th Oct. 2013 N. KIMURA/KEK
Conceptual Design of
the Cryogenics
Low vibration in U. H. Vacuum
Stop propagation of 300K radiation
Prevent heating by scattered beam
80K PTC with
Vibration reduction
4K PTC with
Vibration reduction
Baffles
Main Beam
400kW
two units
~1W
4W?
300K
Radiation Duct Shield
< 1.0 W (< 0.5 W x 2)
Cooling
Cryo-Payload
8K shield
two units
80K shield
Cryostat
Four 4K cryocooler units per one cryostat
 Baffles against wide scattering is cooled via 8K
shield.

ET-meeting, 22th Oct. 2013 N. KIMURA/KEK
Cooling 8K shield
2 units for cool cryo-payload
2 units cool for 8K shield
4 units cool for 80K shield
Structure view of
the Low Vibration Cryo-cooler
Unit
Bellows
バルブ台
Flexible Heat Links
Valve Unit
1m
Part of
Vibration
Reduction Stage
5N8 8K Conduction Bar
80K Cooling passage
Support Frame
(Support: Cold Head)
2m
ET-meeting, 22th Oct. 2013 N. KIMURA/KEK
Vacuum Vessel
(Support: Conduction Paths)
Cooling Time Reduction with Black Coating
To accelerate cooling down by radiation, plated black coating with Diamond
Like Carbon on outer surface of the payload and inner surface of 8K shield.
Items
Materials
Mass
Platform
RM for IM
Almost half !
IM
TM
RM
TM : Test Mass
RM : Recoil Mass
IM : Intermediate Mass
Comparison of Cooling Time with & without DLC
By courtesy of Mr. Y. Sakakibara/ICRR
S.Koike
7
Time Line of KAGRA Cryogenics
2011 Jfy
Apr./’11.
2012 Jfy
Apr./’12
Four Mirror Cryostats
2013 Jfy
Apr./’13
Apr./’14
We are here
22th/Oct.
Manufacture components
Design by KEK
Bidding
Assemble and factory test
with cryo-coolers
Cryo-cooler units
Transport to storage
near Kamioka
Performance test
Design by KEK
Production of seven
cryo-cooler units
with performance
test
Transport to Kamioka
Production of nine
cryo-cooler units
with performance
test
Duct shield units
Design by KEK
ET-meeting, 22th Oct. 2013 N. KIMURA/KEK
Custody at Kamioka
Production of three ducts
shield units
without cryo-coolers
Cryo-payload
Performance
of the CryostatEsti. (W)
◦ Payload
◦ Mirror Adsorption
Total
W/unit
8K Shield
◦
◦
◦
◦
◦
Performance test
at Toshiba Keihin Product
•
•
(~1.0?)
(~1.0?)
(2.0 ?)
(1.0 ?)
Esti. (W)
View Ports
Radiation From 80 K
Support post and Rods
Electrical wires
Duct Shields (~ 5m)
Total
W/unit
80K Shield
Meas. (W)
0.4
Meas. (W)
(0.4)*
2.2
2.4
3 x 10-4
( < 1.0 ?)
4.6 (6.0 ?)
<2.0
2.3 (3.0 ?)
<1.0
Est. (W)
Meas. (W)
◦ Eleven View Ports
It took 12.5 days to cool
down from 300 K(22)
to 8K. ◦ Radiation From 300 K 70
Cool down time of the◦ cryostat
was
Support post
andalmost
Rods 24consistent
with the predicted cooing
timewires
by Calculation
◦ Electrical
3 x 10-4model.
Total
W/unit
ET-meeting, 22th Oct. 2013 N. KIMURA/KEK
94 (116)
24 (29)
125
31
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: one fifth
– Thermal contact resistance between payloads and heat links, etc.
Emissivity
Sapphire: 0.5
Platform: 0.3*(T/300K)
ET-meeting, 22th Oct. 2013 N. KIMURA/KEK
IM: 0.4*(T/300K)
of literature!
By courtesy of Mr. Y. Sakakibara/ICRR
Cooling test in Toshiba
Heat Load Response Test
Heater and thermometer
Pulse tube
cryocoolers
Pulse tube
cryocoolers
Sapphire mirror
Pulse tube
cryocoolers
11
Cooling test @ Toshiba
Result of Heat Load Response @ 8K Radiation Shield
Mirror Operation (~23K)
5 W ~ 12.5 ppm
10 W ~25 ppm
2 W~ 5 ppm
0 W ~0 ppm
Qradiation < α(T48K-T4mirror)
It is confirmed
that 25
ppmpower
(10 W)
kW of
scattered
loss is
Scatted
light
is 4@400
W @400
kW
beam power
acceptable as when
heat scattered
load for the
via the
8 K radiation
shield.
losscryocoolers
on the mirror
surface
is 10 ppm.
12
Performance Test of the Prototype
Duct Shield
Done by Mr. Y.
Measurement of thermal radiation Sakakibara/ICRR
1.
1. 150 K
Thermal Radiation
1. 250 K
1. 600 mm
1. 40 K
1. 250 mm
1. 17 m
Two aluminum plates suspended
1. 600 mm plate (Left side) is heated up to 300 K and emits thermal radiation
2. 250 mm plate (Right side) absorbs radiation and is heated up
3. Calibration is conducted using heater on 250 mm plate
4. ET-meeting,
Coated with
Solblack®
toKIMURA/KEK
enhance emissivity or absorptivity
22th
Oct. 2013 N.
1.
1
Preliminary Results
2
10
1
Heat[W]
10
courtesy
0
10
Reflectivity at 10 um
Duct
0.94±0.02
Solblack0.3±0.1
-1
10
-2
10
Radiated
by Big Plate
Absorbed
Absorbed
by Small Plate by Small Plate
(measured)
 Calculated value (calculation)
has error of several
times
Measuredduct
reflectivity
at 10
μm of
shield
has
error
It was◦ confirmed
shield could
reduce
99.9
% of
heat
◦ Rays are
reflected by shield many times
to cryogenic
payload.
ET-meeting,
Measured
value
isN.within
the error
22th Oct.
2013
KIMURA/KEK
14
By courtesy of Mr. Y. Sakakibara/ICRR
Measurement of scattered light
635 nm, 4.5 mW
~200 ppm of laser light
came back to camera

Red light from laser diode
◦ Photographs of scattered
light when angle changes
Background
◦ Calibration by changing
exposure time
◦ Future work:Vibration
measurement, calculation
of equivalent GW
amplitude
ET-meeting, 22th Oct. 2013 N. KIMURA/KEK
Yusuke Sakakibara
15
Shape of duct shield at each resonant frequency.
Resonant
Frequency
F1 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
F17 77.16 Hz
F18 94.00 Hz
F19 96.18 Hz
F20 99.86 Hz
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
Specification
L=5 m -> Qinput < 0.5 W
Baffles
80 K Duct Shield
Bellows
Support Frame
Vacuum Vessel
5m
ET-meeting, 22th Oct. 2013 N. KIMURA/KEK
Summary
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
Finally,
we
could
achieve
the
big
mile
stone
confirmed and verified;
which• completed
the cryostats
onsixteen
time!
The cooling and vibration
performance of
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
ET-meeting,
22th Oct. 2013 N.
KIMURA/KEK
performance
test.
18