Results from first tests of TRD prototypes for CBM. DPG Frühjahrstagung Münster 2011 Pascal Dillenseger Institut für Kernphysik Frankfurt am Main

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1 Results from first tests of TRD prototypes for CBM DPG Frühjahrstagung Münster 2011 Pascal Dillenseger Institut für Kernphysik

2 Contents Overview of the CBM experiment CBM-TRD General TRD requirements The IKF CBM-TRD Laboratory performance measurements CERN Nov CBM-TRD testbeam Setup Preliminary results Pascal Dillenseger Institut für Kernphysik 2

3 The CBM experiment The dedicated heavy ion experiment at FAIR Study phase diagram at low energies but high densities Accelerators SIS 100: 27 GeV/u for U 92+ 5*10 11 Ions per bunch SIS 300: Observables 35 GeV/u for U 92+ Charmonium, direct photons 3

Accelerators SIS 100: 27 GeV/u for U 92+ 5*10 11 Ions per

4 The electron identification setup Vertex reconstruction and momentum measurement: Micro-Vertex Detector Silicon Tracking System Particle IDentification (PID): Ring Imaging CHerenkov Transition Radiation Detector 3 stations with 4 layers each Time Of Flight EM Calorimeter 4

IDentification (PID): Ring Imaging CHerenkov Transition Radiation

5 TRD requirements The TRD will be used as an electron identification detector a tracking detector Main difficulties are the expected high hit rates up to 140 khz/cm² the big area ( 1000m² ) that needs to be covered CBM TRD-Developement at the IKF Pascal Dillenseger 5

the expected high hit rates up to 140 khz/cm² the big area (

6 Design specifications High rates -> fast readout Big area -> easy and economic to build Good PID -> Pion rejection factor (PRF) 100 Tracking capability There are several different attemps, build an tested by working groups from: Münster, Dubna, Bucharest and Frankfurt 6

Tracking capability There are several different attemps, build an

7 The attempt of the IKF A MultiWire Proportional Chamber (MWPC) with: a small gas gap a small wire pitch no drift region 7

8 The prototypes Four prototypes with different gas gaps and wire pitches have been build 6 mm gas gap - 2 mm wire pitch 6 mm gas gap - 3 mm wire pitch 10 mm gas gap - 5 mm wire pitch 10 mm gas gap mm wire pitch 8

wire pitch 6 mm gas gap - 3 mm wire pitch 10 mm gas

9 Laboratory performance Energy resolution Measured with an 55 Fe x-ray source Fe-K α -Peak 5,9 kev Ar-Escape-Peak 2,9 kev Gas mixture Ar/CO 2 (85%/15%) measurements 9

10 55 Fe spectra CBM-TRD 6 mm gas gap 3 mm wire pitch U a = 1450 V ΔE = 0,289 CBM-TRD 10 mm gas gap 2.5 mm wire pitch U a = 2440 V ΔE = 0,298 10

11 Testbeam setup 11

12 Testbeam specifications CERN PS accelerator Prototypes with 10 mm gas gap were tested An ALICE type radiator was used Used gas mixtures were Ar/CO 2 (80%/20%) Xe/CO 2 (80%/20%) High voltage set up 1800 V for the chamber with 5 mm wire pitch 2440 V for the chamber with 2.5 mm wire pitch 12

Ar/CO 2 (80%/20%) Xe/CO 2 (80%/20%) High voltage set up 1800 V for the

13 Front-end-electronics As readout electronics the SPADIC-chip and the SUSIBO-board were used Self-triggered Pulse Amplification and Digitization asic 8 channels 90 ns shaping time 8 Bit ADC Sampling rate 25 MHz SUSIBO-board is a Virtex 5 board with which the data can be transferred to the pc via FTDI-chip 13

asic 8 channels 90 ns shaping time 8 Bit ADC Sampling rate 25 MHz

14 Preliminary results Single event from the testbeam readout with the spadic-chip Raw data Same event baseline corrected and background subtracted 14

15 Electron-Pion Spectra for 5 GeV/c beam Xe/CO 2 (80%/20%) 10 mm gas gap 5 mm wire pitch 10 mm gas gap 2.5 mm wire pitch Simulations Patrick Reichelt - HK Testbeam data analysis Weilin Yu 15

16 Summary Fast and easy to build TRD is needed Solution flat symmetric MWPC without a drift region Good performance in measurements with 55 Fe x-ray source Good performance at CERN testbeam 16

Information about the T9 beam line and experimental facilities

Information about the T9 beam line and experimental facilities The incoming proton beam from the PS accelerator impinges on the North target and thus produces the particles for the T9 beam line. The collisions