TPC performance in magnetic fields with GEM and pad readout

A novel charged particle tracking device, a high precision time projection chamber (TPC) with gas electron multiplier and pad readout, is a leading candidate as the central tracker for an experiment at the International Linear Collider. To characterize the performance of such a system, a small TPC has been operated within a magnetic field, measuring cosmic ray and laser tracks. Good tracking resolution and two particle separation, sufficient for a large scale ILC central tracker, are achieved.