Results from first tests of TRD prototypes for CBM

1. Results from first tests of TRD prototypes for CBM DPG FrühjahrstagungMünster 2011 Pascal Dillenseger InstitutfürKernphysik Frankfurt am Main

2. Contents • Overview of the CBM experiment • CBM-TRD • General TRD requirements • The IKF CBM-TRD • Laboratory performance measurements • CERN Nov. 2010 CBM-TRD testbeam • Setup • Preliminary results Pascal Dillenseger Institut für Kernphysik Frankfurt am Main

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 U92+ • 5*1011 Ions per bunch • SIS 300: • 35 GeV/u for U92+ • Observables • Charmonium, direct photons… Pascal Dillenseger Institut für Kernphysik Frankfurt am Main

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

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

6. Design specifications • High rates -> fast readout • Big area -> easy and economicto 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 Pascal Dillenseger Institut für Kernphysik Frankfurt am Main

7. The attempt of the IKF A MultiWire Proportional Chamber (MWPC) with: • a small gas gap • a small wire pitch • no drift region Pascal Dillenseger Institut für Kernphysik Frankfurt am Main

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 - 2.5 mm wire pitch Pascal Dillenseger Institut für Kernphysik Frankfurt am Main

9. Laboratory performance measurements Energy resolution • Measured with an 55Fe x-ray source • Fe-Kα-Peak 5,9 keV • Ar-Escape-Peak 2,9 keV • Gas mixture Ar/CO2 (85%/15%) Pascal Dillenseger Institut für Kernphysik Frankfurt am Main

10. 55Fe spectra CBM-TRD 6 mm gas gap 3 mm wire pitch Ua= 1450 V ΔE = 0,289 CBM-TRD 10 mm gas gap 2.5 mm wire pitch Ua= 2440 V ΔE = 0,298 Pascal Dillenseger Institut für Kernphysik Frankfurt am Main

11. Testbeam setup Pascal Dillenseger Institut für Kernphysik Frankfurt am Main

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/CO2 (80%/20%) • Xe/CO2 (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 Pascal Dillenseger Institut für Kernphysik Frankfurt am Main

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 Pascal Dillenseger Institut für Kernphysik Frankfurt am Main

14. Preliminary results Single event from the testbeam readout with the spadic-chip Raw data Same event baseline corrected and background subtracted Pascal Dillenseger Institut für Kernphysik Frankfurt am Main

15. Electron-Pion Spectra for 5 GeV/c beam Xe/CO2 (80%/20%) 10 mm gas gap 5 mm wire pitch 10 mm gas gap 2.5 mm wire pitch Simulations Patrick Reichelt - HK 39.46 – TestbeamdataanalysisWeilinYu Pascal Dillenseger Institut für Kernphysik Frankfurt am Main

16. Summary • Fast and easy to build TRD is needed • Solution… flat symmetric MWPC without a drift region • Good performance in measurements with 55Fe x-ray source • Good performance at CERN testbeam Pascal Dillenseger Institut für Kernphysik Frankfurt am Main