Test Beam Data Analysis for a Timepix3 Readout Chip

The vertex and tracker detector R&D for a future linear collider (CLICdp) aims at developing new silicon sensor technologies. The EP-LCD group has been helping develop a novel pixel detector chip called the Timepix3 with a very thick active silicon layer (675 μm). This thick detector can be used to reconstruct the track incidence angle using the charge drift-time information. To evaluate the principle, test beam data was taken in October 2015 and June 2016 with the Timepix3 at various angles to the beam. The data was analysed to evaluate the sensors performance in calculating the track incidence angle. The device angle was determined using three methods: the first using the cluster size information, secondly using the timing information, and finally using a multivariate analysis technique. The timing method proved the principle of the Timepix3 track angle measurements but the MVA method was found to give much better results, especially for smaller angles, than the other two methods and requires fewer calculations.The effect of the bias voltage on the calculated angle was also investigated for the timing method however no overall conclusions could be made.