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

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 2 Pascal Dillenseger Institut für Kernphysik Frankfurt am Main

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: – 35 GeV/u for U 92+ Observables Charmonium, direct photons… Pascal Dillenseger Institut für Kernphysik Frankfurt am Main 3

The electron identification setup 4 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

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

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 Pascal Dillenseger Institut für Kernphysik Frankfurt am Main 6

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 7

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 Pascal Dillenseger Institut für Kernphysik Frankfurt am Main 8

Laboratory performance measurements 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%) Pascal Dillenseger Institut für Kernphysik Frankfurt am Main 9

55 Fe spectra Pascal Dillenseger Institut für Kernphysik Frankfurt am Main 10 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

Testbeam setup Pascal Dillenseger Institut für Kernphysik Frankfurt am Main 11

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 Pascal Dillenseger Institut für Kernphysik Frankfurt am Main 12

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 13

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

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 Pascal Dillenseger Institut für Kernphysik Frankfurt am Main 15 Simulations Patrick Reichelt - HK – Testbeam data analysis Weilin Yu

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 Pascal Dillenseger Institut für Kernphysik Frankfurt am Main 16