Heidelberg 2015 – wissenschaftliches Programm

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HK: Fachverband Physik der Hadronen und Kerne

HK 22: Instrumentation 8

HK 22.3: Vortrag

Dienstag, 24. März 2015, 15:00–15:15, M/HS2

Energy resolution studies of an IROC GEM prototype for the ALICE TPC — •Andreas Mathis for the ALICE collaboration — TU München, Physik Department E12, Excellence Cluster "Universe", D-85748, Garching, Germany

The ALICE collaboration (A Large Ion Collider Experiment) is planning an upgrade of its central barrel detectors, to be able to cope with the increased LHC luminosity beyond 2018. In order to fully exploit the increase in collision rate to about 50 kHz in Pb−Pb, the TPC is foreseen to be operated in an ungated mode with continuous readout. This demands for a replacement of the currently used, gated MWPC by GEM-based readout chambers, while retaining the present tracking and particle identification capabilities of the TPC via measurement of the specific energy loss (dE/dx).

The present baseline solution for the TPC upgrade consists of a stack of four large-sized GEM foils as amplification stage, containing both Standard (S, 140 µm) and Large Pitch (LP, 280 µm) GEM foils arranged in the order S-LP-LP-S. This arrangement has been proven as advantageous in terms of ion backflow and energy resolution.

A prototype of an ALICE IROC (Inner Readout Chamber) was equipped with such a quadruple GEM stack, installed inside a field cage and exposed to a beam of electrons and pions from the CERN PS. The performance of the prototype in terms of energy resolution has been evaluated and will be presented.

This work has been supported by BMBF 05P12WOGHH and DFG Cluster of Excellence Origin and Structure of the Universe.