Monolithic Thin Pixel Upgrade –Testing Update

Gary S. Varner, Marlon Barbero and Fang FangUH Belle Meeting, April 30th 2004

1Marlon Barbero, Apr 30th 2004, UHBELLE Meeting

Critical R&D Items

1. Readout Speed

2.Radiation Hardness

3.Thin Detector

4.Full-sized detector

2Marlon Barbero, Apr 30th 2004, UHBELLE Meeting

Leakage Current

Leakage Current [fA]

BeforeIrradiation

# of

pix

els

1-2fA/pixel common

To be irradiated

3Marlon Barbero, Apr 30th 2004, UHBELLE Meeting

Irrad. detector: Leakage Current

VERY PRELIMINARY

Leakage Current [fA]

12-18fA/pixel common

After 200KradIrradiation

# of

pix

els

13Apr04

4Marlon Barbero, Apr 30th 2004, UHBELLE Meeting

Leakage Current (cont.)

Leakage Current [fA]

# of

pix

els

Before irrad.

200 Krad

5Marlon Barbero, Apr 30th 2004, UHBELLE Meeting

Leakage Current (cont.)

0.35mm CMOS APS Leakage Current

100

1000

10000

100000

0.001 0.01 0.1 1 10 100

Radiation [MRad]

Leak

age

curr

ent [

pA/c

m2]

Eid et al.CAP1

CAP1 no annealing

Eid et al.

IEEE Trans. on Nucl. Sc.

Vol. 48, No 6, Dec 2001

Rem:

• up to 30Mrad!!!

• large “error bars”: 4 geometries

6Marlon Barbero, Apr 30th 2004, UHBELLE Meeting

2 Mrad detector?

NO DATA AVAILABLE!!!

Broken during manipulation

7Marlon Barbero, Apr 30th 2004, UHBELLE Meeting

SNR CAP1 / CAP2

SNR vs. Irradiation (550e- signal, 25e- system noise)

0

5

10

15

20

25

0.01 0.1 1 10 100

Radiation dose [MRad]

Sig

nal-t

o-N

oise

Rat

io (S

NR)

8ms10us100us1ms

• Extrapolation at high dose from Eid et al results.

• Degradation of SNR: system noise + leakage current pixel.

• CAP1: self triggering mode: need to maximize integration time to processing time ratio. “Large” integration times.

• CAP2: triggered from the outside. Buffer inside each pixel. Integration time very small.

CAP2: Even at high doses, leakage current is negligible. SNR stays of order 22

8Marlon Barbero, Apr 30th 2004, UHBELLE Meeting

SNR CAP1 / CAP2: 10e- noise?

SNR vs. Irradiation (550e- signal, 10e- system noise)

0

10

20

30

40

50

60

0.01 0.1 1 10 100

Radiation dose [MRad]

Sign

al-to

-Noi

se R

atio

(SNR

)

8ms10us100us1ms

9Marlon Barbero, Apr 30th 2004, UHBELLE Meeting

3-layer correlation

Co60 runs.

19APR04, Evt32.

10Marlon Barbero, Apr 30th 2004, UHBELLE Meeting

3-layer correlation

Co60 runs.

19APR04, Evt18.

11Marlon Barbero, Apr 30th 2004, UHBELLE Meeting

3-layer correlation

Co60 runs.

19APR04, Evt22.

12Marlon Barbero, Apr 30th 2004, UHBELLE Meeting

Conclusion

• Irradiation studies• Wait for 2Mrad detector.

• New Front End Board F2 and Back End Board B2ADC on F2, new data readout path, no more analog cable between Front end and acquisition card.

• Should improve noise levels and speed the data transfer.• Gain experience with new F2 board (readout).• Suitable firmware is being developed, both for CAP1 and CAP2.

• Get ready for beam test• Plans for the beam test will be given next meeting.

13Marlon Barbero, Apr 30th 2004, UHBELLE Meeting

SNR CAP1 for C060 runsAsk for coincidence of 3

out of 4 detectors

Layer A

Layer B

Layer C

All 4 layers

14Marlon Barbero, Apr 30th 2004, UHBELLE Meeting

SNR CAP1 for C060 runsAsk for coincidence of 3

out of 4 detectors

Layer A

Layer B

Layer C

Layer D

15Marlon Barbero, Apr 30th 2004, UHBELLE Meeting

SNR CAP1 / CAP2

SNR vs. Irradiation (550e- signal, 25e- system noise)

0

5

10

15

20

25

0.01 0.1 1 10 100

Radiation dose [MRad]

Sign

al-to

-Noi

se R

atio

(SN

R)

CAP1 [8ms]CAP2 [10us]

• Extrapolation at high dose from Eid et al results.

• Degradation of SNR: system noise + leakage current pixel.

• CAP1: self triggering mode: need to maximize integration time to processing time ratio. “Large” integration times.

• CAP2: triggered from the outside. Buffer inside each pixel. Integration time very small.

CAP2: Even at high doses, leakage current is negligible. SNR stays of order 22

Basic Technology: Standard CMOS

16Marlon Barbero, Apr 30th 2004, UHBELLE Meeting

CMOS Camera ParticleDetector

Key Features:• q collection via thermal diffusion (no HV)• NO bump bonding• “System on Chip”possible

Standard CMOS:•Low Power•Excellent Transistors•Tight Process Control•Excellent Uniformity•High volume, low cost•Large ADC, DSP base

Because of largeCapacitance, need

Thick DSSDs-- APS can be VERY

Thin

17Marlon Barbero, Apr 30th 2004, UHBELLE Meeting

Continuous Acquisition Pixel (CAP)

• Conceptually Simple– Analog reset, take sample frame and then difference– Continuous “Correlated Double Sampling”– Row-wise analog shift out as fast as possible:

• Consider 22.5µm square pixels• A few µm resolution possible for good SNR• Readout speed limited by analog settling

ADCArray of 132X48 pixels High-speedStandard

APS pixel

analog

& storageLow power – only significant

draw at readout edgePixel Array: Column select – ganged row read

18Marlon Barbero, Apr 30th 2004, UHBELLE Meeting

Prototype Test Bench

Compact PCI (cPCI)based

19Marlon Barbero, Apr 30th 2004, UHBELLE Meeting

Sampling Cycle

Pixel Readout Structure

0

0.2

0.4

0.6

0.8

1

1.2

1.4

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000t (nsec.)

Pixel array complete acquisition (fr1/fr2)

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

-2.00E-03 0.00E+00 2.00E-03 4.00E-03 6.00E-03 8.00E-03 1.00E-02 1.20E-02

8ms integration

~33ms cycle~30 Hz acquisition

8448 samplestransferred

Frame 1 Frame 2

Transfer to CPU onPCI bus (not DMA)

50 ohm cable settling timedominated

Analog reset

8MSa/s readout

20Marlon Barbero, Apr 30th 2004, UHBELLE Meeting

Charge Collection Efficiency

Pixel Collected Deposited Energy

~10µm

Epi

bulk

β- emitter

316keV e- dE/dx ~ 323eV/µm

mip dE/dx ~ 267eV/µm

Will CheckAfter

Irradiation

Landau fit