Computer simulations and performance measurements on a silicon strip detector for edge-on imaging

Abstract

Silicon strip detectors to be used edge-on for imaging in a scanned slit geometry have been simulated. A software program was developed which can simulate the motion of free charges in the bulk detector and calculate the signals they induce on the electrodes. The purpose was to quantify the impact of charge sharing on system detective quantum efficiency (DQE). The energy spectrum that was used in this study is typical for mammography. The detectors are working in single photon counting mode and the optimal threshold level to discriminate noise from useful signals has been calculated. The loss in detective quantum efficiency due to charge sharing was found to be around 5% for a 100 /spl mu/m pitched detector. Coincidence circuits can be included in the electronics to eliminate this problem. Furthermore, it is described how the relationship between charge collection efficiency and photon interaction position in the detector can be measured.