High resolution TPC based on optically readout GEM

Large granularity and high sensitivity commercial CMOS readout systems open the possibility of developing particle detectors with very interesting performance for different applications, from the search of rare and exotics events, such as dark matter directional candidates, to high quality neutron/ion/hadron beam monitor, mainly for medical applications. The gas scintillation mechanisms was exploited for starting an R&D on large TPC-based detector, equipped with a Triple GEM amplification stage optically readout. By this approach, a 7 l sensitive volume detector was built and tested. Space resolutions of 35μm on the GEM plane (X, Y) and 100μm on Z and energy measurements with a precision of about 25% were obtained. Analysis of the track shapes provides precious information allowing very good particle discrimination.