  A large number of high-energy and heavy-ion experiments successfully used
Time Projection Chamber (TPC) as central tracker and particle identification
detector. However, the performance requirements on TPC for new high-rate
particle experiments greatly exceed the abilities of traditional TPC read out
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 detector built as a prototype for the inner part for AMADEUS, a
new experimental proposal at the DAFNE collider at Laboratori Nazionali di
Frascati (INFN), aiming to perform measurements of the low-energy negative
kaons interactions in nuclei. In order to evaluate the GEM-TPC performances, a
10x10 cm2 prototype with a drift gap up to 15 cm has been realized. The
detector was tested at the pM1 beam facility of the Paul Scherrer Institut
(PSI) with low momentum pions and protons, without magnetic field. Drift
properties of argonisobutane gas mixtures are measured and compared
withMagboltz prediction. Detection efficiency and spatial resolution as a
function of a large number of parameters, such as the gas gain, the drift
field, the front-end electronic threshold and particle momentum, are
illustrated and discussed. Particle identification capability and the
measurement of the energy resolution in isobutane-based gas mixture are also
reported.
