Tilted CMOS active pixel sensors for particle track reconstruction

In this work, we propose an innovative approach to characterize CMOS Active Pixel Sensors to be used for particle track reconstruction. The main idea is to use three pixel layers in the conventional way (e.g. orthogonally disposed with respect to the particle trajectory), whereas a fourth layer can be tilted with respect to the others up to 90 degrees. This would potentially allow for a better track reconstruction, thanks to the big number of reconstruction points. In order to check the suitability of the approach a dedicated tracking system featuring four sensors of 256×256 pixels has been assembled and tested at the INFN BTF, Frascati (Italy). Test results demonstrate the suitability of the approach, e.g. the system sensitivity to tilted trajectories.