Induced current signals in planar pn diodes for Light Charged Products identification

The design of modern multi-detector arrays for intermediate energy nuclear physics experiments has to face the problem of the improvement of the charge and mass identification of heavy and light charged products. Processing techniques based on the pulse-shape analysis of the signals delivered by the silicon detector units are powerful tools to identify the reaction products stopping in the silicon layer. Due to the interrelations between several parameters, the optimization of the detector-frontend system and of the processing technique require the simulation of carrier generation, transport and signal formation with a fast and accurate simulator to be effective. To this aim we developed a code based on a semi-analytical method for 3D potential calculation in semiconductor detectors that includes also thermal diffusion of the carriers and Coulomb interaction between the carriers. We have developed also a simplified analytical model of the induced current signals, which has been used as a precious guide for interpretation of the simulation results. The induced current signals have been simulated for the interaction of several ions in the case of both "front-side" and "reverse-side" mounting. Such study is the basis for the interpretation of the experimental results and for the optimization of the detector topology and operating parameters.