Mariana Petris, NIPNE Bucharest CBM Meeting, March 9 -12, 2005

HIGH COUNTING RATE TRANSITION RADIATION

DETECTORBucharest Prototype

In Beam Tests

Transition Radiation Detectors

ALICE - TRD ATLAS - TRT

- type (radiator+drift chamber + MWPC) (radiator + straw tubes)

- rej (at 90% e efficiency) 100 100

- Maximum drift time 2 s 40 ns

- Counting rates ~ 100 Hz/cm2 ~ 1MHz/ cm2

- Granularity (channel size) high (~6 cm2) low (~20cm2) CBM - TRD

Counting rates ~ 100 KHz/cm2

High granularity

- rej (at 90% e efficiency) > 100

HCRTRD - prototype

- type: radiator + MWPC; 2.5 mm anode pitch

- maximum drift time: ~ 100 ns

- channel size: 6 cm2

55Fe Source Tests

IFIN - HH 55Fe tests

30% CO2 + 70% Ar

HV 1920 V;

Readout: PASA (2 mV/fC, 1800 e

rms) + ADC Converter

Energy Resolution :

~10% ();

~25% FWHM

GSI 55Fe tests

15% CO2 + 85% Ar

HV 1700 V;

Readout:PASA (2mV/fC, 1800 e

rms) + FADC Converter

Energy Resolution:

~ 8.6 % ();

~20 % FWHM

Beam Test

Goal of the experiment: detector performance in high counting rate environment

Experimental Setup:

- 2 Scintillators (ToF, trigger);

- 2 Si - Strip Detectors (position information);

- 2 MWPC - GSI (10 x 10 cm2 )

- 1 MWPC - Bucharest (24 x 24 cm2 )

-1 MWPC - Dubna (10 x 10 cm2 )

- 1 GEM - Dubna

- Pb - glass calorimeter (last run)

- FADC readout ; DAQ (MBS)

Beam Composition

e/ vs. rate not possible, too low e intensities at SIS

/p @ 1 GeV/c too low rates;

p/d @ 2 GeV/c rate dependence studies.

p

p p d

p d

Beam Profile

x1 > 10 mm; x2 > 10 mm;

Si1 length 20;

Si2 length 20.

2 s 2 s

0.2 s 0.2 s

2 s

1850 V

0.2 s

1850 V

Gain - 2s spill length,for protons

Average Pulse Height15% CO2 + 85% Ar, continuous anode, 1750 V 15%CO2 + 85% Ar, split anode, 1725 V

1 s

0.5 s

<P

H>

(mV

/0.7

4) 2 s

1 s

0.5 s

0.2 s

2 s

1 s

0.5 s

0.2 s

0 %

0.7 %

3.5 %

13.3%

0 %

0 %

0 %

2%

ToF Spectra

Pulse Height and Charge Spectra

e/ Discrimination

Pulse Height and Charge Spectra

MPV value (from landau fit of PH and Q proton spectra) as a function of rate

High Counting Rate Effect

(4.2 1.2) %

(3.2 2.1) %

(11.7 1.8) %

(0.4 1) %

High Counting Rate Effect

(8.9 1.4) %

(5 3.4) %

(8.4 3.9) %

(2.2 1.4) %

High Counting Rate Effect

(6.8 1.5) %

(3.2 1.1) %

(5.8 1.9) %

(3.4 1.5) %

Conclusions

•Diagnostic system

not specific for hcr

environment

limited performance

The results of the first in-beam tests of such a geometry seem to

recommend it as a solution for a major percentage of the CBM

TRD subdetector.

Participants: Bucharest, Dubna, GSI, Heidelberg and Münster

•Modest statistics

limiting factor for

detailed analysis in terms

of:

- Beam profile

- Spill profile

•Much to low

systematics for

negatives (e/)

Although