Mainz 2012 – scientific programme
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HK: Fachverband Physik der Hadronen und Kerne
HK 30: Hadronenstruktur und -spektroskopie
HK 30.8: Talk
Wednesday, March 21, 2012, 18:30–18:45, RW 1
Performance of a TPC with GEM amplification in the FOPI spectrometer.* — •Martin Berger — TU München, Boltzmannstr. 2, 85748 Garching, Germany
A GEM-TPC can exploit the intrinsic suppression of back drifting ions from the amplification stage of the GEM foils to overcome the problem of drift-field distortions in an
ungated operation.
To explore the possibility of a continuously running TPC (Time Projection Chamber) with GEM (Gas Electron Multiplier) foils instead of MWPC’s as amplification stage
a prototype detector was built.
This prototype with a drift length of 728 mm and a radius of 308 mm and a total of 10254 electronic channels was designed as an upgrade for the FOPI experiment
at GSI to improve the secondary vertex resolution especially for KS0 and Λ and the PID capabilities for K+and K− fit into the FOPI spectrometer.
Several measurements with cosmic rays, ion beams colliding with solid targets [1] and physics run with a π-beam were carried out.
During these tests different gain settings, drift fields and gas mixtures have been used to study systematically the response of the chamber.
The signal pattern and the spatial resolution extracted by the differential analysis of cosmics data will be discussed in this contribution.
*Supported by BMBF and DFG Cluster of Excellence "Universe" (Exc153).
1L. Fabbietti, Nucl. Instr. and Meth. A, 628 204-208 (2011)