Darmstadt 2016 – wissenschaftliches Programm

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HK: Fachverband Physik der Hadronen und Kerne

HK 61: Instrumentation XVIII

HK 61.4: Vortrag

Donnerstag, 17. März 2016, 17:30–17:45, S1/01 A2

Performance studies with the quadruple GEM detectors for the ALICE TPC upgrade — Piotr Gasik and •Andreas Mathis for the ALICE collaboration — TU München, Physik Department E62, Excellence Cluster ’Universe’, D-85748 Garching, Germany

The ALICE Collaboration is planning a major upgrade of its central barrel detectors to be able to cope with the increased LHC luminosity beyond 2019. In order to record at an increased interaction rate of 50 kHz in Pb–Pb collisions, the TPC will be operated in an ungated mode with continuous readout. This demands for a replacement of the currently used gated MWPC (Multi-Wire Proportional Chamber) by GEM-based (Gas Electron Multiplier) readout chambers, while retaining the performance in particular in terms of particle identification capabilities via the measurement of the specific energy loss.

The present baseline solution for the TPC upgrade consists of a stack of four large-size GEM foils as amplification stage. An extensive R&D program with small detector prototypes has yielded a specific voltage configuration fulfilling the design specifications in terms of ion backflow suppression, gain stability, energy and dE/dx resolution and stability against discharges. Moreover, large-size prototypes have been built in order to validate the production techniques and the performance with respect to operational stability against electric discharges and dE/dx resolution both with beams and radioactive sources.

This research was supported by the DFG cluster of excellence ’Origin and Structure of the Universe’ and BmBf Verbundsprojekt ALICE at HIG rate 05P15WOCA1.