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

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FPCCD R&D

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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

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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

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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

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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)

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2-PHASE CO2 COOLING SYSTEM FOR FPCCD VTX

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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

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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

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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

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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

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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)

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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

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SUMMARY AND PLAN

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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

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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

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