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R&D status of FPCCD VTX and its cooling system
Yasuhiro Sugimoto
for FPCCD VTX group
2013/5/28 @ECFA2013
1
Outline
• FPCCD R&D– Prototype sensors– Beam test plan
• 2-phase CO2 cooling system– Motivation– Circulating system using a compressor
2
FPCCD R&D
3
FPCCD sensors
• Small prototype in FY2012– 6mm square image area– 6um pixel size– 4ch/chip with different horizontal shift
register size: 6x6, 6x12, 6x18, 6x24 um2
– It works except for the channel with 6x6um2 horizontal shift register
– Thin wafer (50um) in package with hole for beam test
4
FPCCD sensors• Large prototype
– 62.4x12.3mm2 image area ~ Real size prototype for inner layers– 8ch/chip with several pixel sizes: 4chx6um, 2chx8um,
2chx12um– Large area is achieved by stitching technique: 8 steps with 3
kinds of masks
5
FPCCD sensors
• Large prototype– Packaged sensors have been delivered– Test boards have been prepared– Two channels (out of 8ch) which have 6umx6um horizontal
shift register do not work properly– Full-well capacity is still small (~6k electrons) for 6um pixels
6
Beam test plan
• Test beam at J-PARC in June– 1 GeV/c pion– 3.2mm distance between central 2 layers Minimize multiple
scattering effect– Small prototypes with thin (50um) wafers will be tested– Study items: Spatial resolution, S/N ratio, charge spread, etc.– Could be delayed due to the trouble at J-PARC on May 23
Beam
CCD1~4
SC1
SC2(4ch)
SC3(4ch) 7
FY2013 plan
• Study of 2012 prototypes– Source test / Beam test – Radiation damage test
• Improved small prototypes– Increase full-well capacity– Smaller pixel size: 6um 5um
• Large prototypes– Thin large wafer Prototype ladder in FY2014
• Readout electronics– Improvement of front-end ASIC– Development of a part of peripheral circuits (clock driver, ser-
des, timing generator, or data compression circuits)
8
2-PHASE CO2 COOLING SYSTEM FOR FPCCD VTX
9
Why we need CO2 cooling?
• Power consumption
Readout frequency 10 Mpix/s
Readout time 200 ms
Clock timing Same for inner and outer layers
Vertical shift time 40 us/line
Power consumption 15 mW/ch (On-chip amp + FE ASIC)
Chip size (in/out) 11x62.5mm2 / 22x125mm2
Number of chips (in/out) 40 (=10x2x2) / 112 (=(11+17)x2x2)
Pixel size (in)
Pixel size (out)
# of ch/chip (in)
# of ch/chip (out)
# of ch (total)
Power consumption
5 um 5 um 28 56 7392 111 W
5 um 10 um 15 15 2280 34 W
Power consumption in aluminum gate lines should be added We should assume >50W power consumption
10
11
Why we need CO2 cooling?
• Operation temperature– Optimization for radiation
tolerance– Charge transfer inefficiency
(CTI) due to radiation damage is a function of temperature
– A simple simulation of CTI based on Shockley-Read-Hall theory shows around -40℃ is optimal
– 2-phase CO2 cooling gives constant temperature cooling
~1x1011 e/cm2
Why we need CO2 cooling?
• Material budget / dead region– 2-phase CO2 can go through very thin cooling tube (OD 2mm or
less) Only 0.3%X0 increase of material budget of the end-plate
– Gas cooling requires much thicker tube Dead space between FTD and beam pipe
12
13
Advantages of CO2 cooling
• Large latent heat ~300 J/g (x3 of PFC)• High pressure ~1 MPa @-40℃
– Less evaporated gas volume– Less temperature drop due to pressure drop
We can use thin cooling tube
• Much less Global Warming Potential
CO2 C2F6 C3F8
Latent heat @-40C 321 J/g ~100 J/g ~110 J/g
Critical point 31.1℃ 19.7℃ 71.9℃
Pressure @-40C 1 MPa ~0.5 MPa ~0.1 MPa
GWP 1 9200 7000
14
CO2 blow system
• First step towards circulating system – We constructed “blow system” and temperature was
successfully controlled between -40℃ and +15℃
Circulating system
• Circulating system using a liquid CO2 pump– Getting popular in HE physics experiments– Disadvantages in low temperature application
CO2
2-phase accumulator
PID
Chiller<-40C
Condenser
Liquid pump
DumperHEX
Detector
Restrictor
Expensive
Heat loadHeat load
Heat load
15
Circulating system
• Circulating system using a CO2 gas compressor– Less expensive for low temperature application
CO2
Chiller Condenser
BufferBack-pressurevalve
Heat exchanger
Restrictor
Detector
Heater
Driving air-compressorPa <0.8 MPa, ~400L/min
Gas boosterAGD-7Po < 7Pa + Ps
5~20℃
Buffer
Flow Meter
Regulator
Inexpensive(Cooling water line)
Close to room temp.(Cooling plant)
(Detector side)
16
Development of circulating system
• Cooling plant for R&D many sensors attached• Assembly completed to be tested after July
T
T
F2V5
F4
Chiller5~20℃
J4
J3
V3
D
駆動用エアコンプレッサーPa <0.8 MPa,~400L/min
CO2(ヒーター付レギュレータ使用)
1/4"または接触(温度センサ)3/8"1/2"電気配線
P
T
24V
P24V
T
P
24V
DI3 24V DMAC100V
RU24V
T
P 24V
TT
P
T
P24V DI1
DI224V
T
TCDC
AC100V
AC100V
P24V
GB
Buffer1
Buffer2
J1
J2
J5
J6
J8 J9 J7
Vacuum Vent Vent
V1
V2
V4
V6
V7
V8
V9
V10
V11
RV1RV2
RV3
RV4
RV5
M1
M2
DI424V
DI524V
M4CV
P1
P2
P3
P4
P5
P6P7
F1
Heat bath
M3F3
HEX
2012/12/5
DC24VAC100V
DataLogger
20ch
17
SUMMARY AND PLAN
18
Summary
• FPCCD small prototype with 6um pixel size has been developed and worked well if the horizontal shift register size is 6umx12um or larger
• Large prototype of FPCCD has been developed and the packaged prototype sensors have been delivered
• FPCCD VTX will be operated at -40℃ with 2-phase CO2 cooling system
• Circulating CO2 cooling system using a CO2 gas compressor seems attractive
• A test system for the circulating CO2 cooling system with a gas compressor has been designed and assembled
19
Future prospect
• R&D goal for coming 3 years– 5um pixel– Demonstration of performance– Peripheral circuits for demonstration– Prototype ladder– Engineering prototype of support structure
• Plan for 2016-2017 (after approval of ILC project)– Very large size prototype for outer layers – Peripheral circuits for real detector– Engineering prototype of support structure– ILD proposal and VTX TDR
20