Tracking performance of GasPixel detectors in test beam studies

A combination of a pixel chip and a gas chamber (GasPixel detectors) opens new opportunities for particle detectors. GasPixel detectors consist of an electron drift volume, an amplification gap and an anode plane based on a semiconductor chip. This technology promises large benefits in high-energy charged-particle tracking. It allows reconstruction of a 3D image of a particle track segment in a single detector layer with high accuracy. Several prototypes of GasPixel detectors based on micromegas technology with different gas mixtures and drift gaps were studied in a test beam. A spatial resolution of 8 μm and angular accuracy of about 0.2° in a chip plane were obtained. A dedicated Monte Carlo simulation of GasPixel detectors shows good agreement with experimental data.