Performances of a GEM-based TPC prototype for new high-rate particle experiments

Abstract

Time projection chamber (TPC) has been successfully used as a central tracker and a particle identification device in a number of a high-energy physics experiments. However, the performance requirements on TPC for new high-rate particle experiments greatly exceed the abilities of traditional TPC readout by multi-wire proportional chamber (MWPC). Gas Electron Multiplier (GEM) detector has great potential to improve TPC performances when used as amplification device. In this paper we present the R&D activity on a new GEM-based TPC (TPG) detector for the inner part of the AMADEUS experiment, a new experimental proposal at DA Φ NE accelerator at LNF, aiming to perform measurements of the low-energy negative kaons interactions in nuclei. In order to evaluate the TPG feasibility, a 10 × 10 cm 2 prototype with a drift length up to 15 cm are designed. The performances of a 10 × 10 cm 2 pre-existing prototype with a reduced drift gap, operated with Ar / CO 2 / CF 4 (45/15/40) gas mixture and successfully tested at BTF facility, are presented. The gas mixture properties, such as the electron drift velocity and the diffusion, have been measured and they result comparable with those simulated with Garfield. A good resolution along the beam direction ( z-coordinate), sufficient for a more large scale TPG in AMADEUS, is achieved.