TRD R&D at GSI

Results from test beam 2004 Plans for test beam Feb. 06 Measurements with X-ray stand

C. Garabatos, GSI

IWTRD Cheile Gradistei 24-28.09.05

C. Garabatos, GSI 2

TR + tracking

• rejection ≤ 10–2

• position resolution ~300 m

• particle load: 105 Hz/cm2

• < 100 ns shaping time

• material budget

• reliability (stability, ageing, ...)

IWTRD Cheile Gradistei 24-28.09.05

C. Garabatos, GSI 3

Solutions under study

• Classical wire chambers

• GEMs

• Straw tubes

• Name: Transition Radiation Detector

GAS

RADIATOR

6 mm

2-4 mm

IWTRD Cheile Gradistei 24-28.09.05

C. Garabatos, GSI 4

Resolution vs. rate (July 04)(E. Jiménez)

0 20 40 60 80 100 1200

100

200

300

400

(

m)

Rate (kHz/cm2)

GSI MWPCs

• Slight degradation with rate• Pad size not optimized

IWTRD Cheile Gradistei 24-28.09.05

C. Garabatos, GSI 5

9o incident angle

IWTRD Cheile Gradistei 24-28.09.05

C. Garabatos, GSI 6

Pad response function

Next: go from 7.5 mm to 7.0 mm pad width

IWTRD Cheile Gradistei 24-28.09.05

C. Garabatos, GSI 7

Next test beam Feb. 2006

• Dedicated test beam line in cave C (HTD)

• Higher rates with N2 source (factor ~5)

• Improved set-up– Trigger counters– Chamber pad planes– Readout electronics

• Dense program

IWTRD Cheile Gradistei 24-28.09.05

C. Garabatos, GSI 8

Beam profile in HTD

IWTRD Cheile Gradistei 24-28.09.05

C. Garabatos, GSI 9

Trigger scintillators for test beam

2004

4x4 cm2 plastics

2006

4x 1x4 cm2 plastics

IWTRD Cheile Gradistei 24-28.09.05

C. Garabatos, GSI 10

Pad geometryfor new prototypes

2004 2006

ALICE geometry: 7.5x70 mm2 CBM geometry: 7x16 mm2

IWTRD Cheile Gradistei 24-28.09.05

C. Garabatos, GSI 11

Readout electronics(H. K. Soltveit)

• New 0.35 m CMOS 16 channel PASA

• Submission end of September

• Enough chips for all test detectors

IWTRD Cheile Gradistei 24-28.09.05

C. Garabatos, GSI 12

Chip parameters (H.-K. S.)

Performance Specified Simulated (typical)

Noise 1000e for pad capacitance between

5- 10pF

350e@5pF

412e@10pF

660e@25pF

Conversion gain 12 mV/fC 12.6 mV/fC

FWHM 70 ns 70 ns

Undershoot - 1mV

Baseline shift - 3mV

Pad capacitance 5-10 pF -

IWTRD Cheile Gradistei 24-28.09.05

C. Garabatos, GSI 13

Program• High rate performance vs.

– Detector flavour and geometry– Gas gain– Gas composition– Incident angle

• e/ separation vs. radiator type (low rates)– Foil radiator

• p/ separation at high rates

IWTRD Cheile Gradistei 24-28.09.05

C. Garabatos, GSI 14

Measurements with X-ray tube

(F. Uhlig, G. Hamar)

IWTRD Cheile Gradistei 24-28.09.05

C. Garabatos, GSI 15

Measurements with X-rays

• Possibility to measure rate dependence on gas gain and gas composition

• Need careful calibration and extrapolation to charged particles

• Easy

• Same set-up will be used for ageing tests

IWTRD Cheile Gradistei 24-28.09.05

C. Garabatos, GSI 16

Results with Argon

• Fit to Mathieson's formula ln(G/G0)/G = K R The constant K characterises the chamber and the gas• Next: Xenon

10 100 1000 100002000

10000

50000

100000

Gai

n

Rate (kHz/cm2)

Ar-CO2 [90-10]

10%5%2%1% gain drop

10 100 1000 100002000

10000

50000

100000

Gai

n

Rate (kHz/cm2)

Ar-CO2 [70-30]

10%5%2%1% gain drop

IWTRD Cheile Gradistei 24-28.09.05

C. Garabatos, GSI 17

Conclusions and outlook

• We start to know what we need

• Tracking and TR-ID with MWPC seem feasible at CBM

• High rates and final performance will be an outcome of – specific, ongoing R&D – detailed, incipient simulations