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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 setup
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
Pascal Dillenseger Institut für Kernphysik Frankfurt am Main
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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
