Resolution Studies of GEM/Timepix Detector with 5 GeV electrons

This contribution investigates a prototype of a TPC readout with a highly pixelated CMOS ASIC, which is an option for charged particles tracking of the ILC. A triple GEM stack was joined with a TimePix and MediPix2 chip (pixel size of 55$\times$55 $\mu m^2$) and its readout properties were investigated with 5 GeV electrons. The spatial resolution of the cluster center reconstruction was determined as a function of drift distance using different cluster alhoritms and compared with Monte Carlo predictions.