Results from first tests of TRD prototypes for CBM DPG Frühjahrstagung Münster 2011 Pascal...
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Transcript of Results from first tests of TRD prototypes for CBM DPG Frühjahrstagung Münster 2011 Pascal...
Results from first tests of TRD prototypes for CBM
DPG Frühjahrstagung Münster 2011Pascal Dillenseger
Institut für Kernphysik Frankfurt am Main
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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
Pascal Dillenseger Institut für Kernphysik Frankfurt am Main
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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…
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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
CBM TRD-Developement at the IKF Pascal Dillenseger
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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
Pascal Dillenseger Institut für Kernphysik Frankfurt am Main
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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
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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
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The prototypes
Four prototypes with different gas gaps and wire pitches havebeen 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
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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
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55Fe spectraCBM-TRD 6 mm gas gap 3 mm wire pitchUa = 1450 VΔE = 0,289
CBM-TRD 10 mm gas gap 2.5 mm wire pitchUa = 2440 VΔE = 0,298
Pascal Dillenseger Institut für Kernphysik Frankfurt am Main
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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
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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
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Single event from the testbeam readout with the spadic-chip
Preliminary results
Raw data Same event baseline corrected and background subtracted
Pascal Dillenseger Institut für Kernphysik Frankfurt am Main
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Electron-Pion Spectra for 5 GeV/c beam Xe/CO2 (80%/20%)
10 mm gas gap5 mm wire pitch
10 mm gas gap 2.5 mm wire pitch
Simulations Patrick Reichelt - HK 39.46 – Testbeam data analysis Weilin Yu