Spatial resolution analysis of micron resolution silicon pixel detectors based on beam and laser tests

Abstract

Pixel sensors with micron resolution are being developed by several groups, and this development comes hand in hand with the development of new resolution enhancement methods specially suited to the new sensors. This paper summarizes the results of our study of hit reconstruction methods used in analysis of Depleted P-Channel Field Effect Transistor (DEPFET) beam test data. The study is based on data of DEPFET beam tests at CERN in 2006 and 2007, and on laser tests using a pulsed 682 nm laser. In beam test data analysis, we used a new method to separate the contributions of intrinsic resolution, multiple scattering and track uncertainty to impact point prediction error. We compared several methods of hit reconstruction for pixel detectors, based either on beam test tracks or on laser matrix scans for a range of laser pulse energies. We show about 20% improvement in the resolutions calculated from the data of two DEPFET beam tests with different detector setups. We also show that impact point correction derived from laser tests can be applied in tracking.