Experimental results of electron confinement in a silicon drift detector with saw tooth shaped p/sup +/ strips

Abstract

Recently it has been experimentally shown that saw tooth shaped p/sup +/ strips allows confinement of drifting electrons in the lateral direction. This is achieved by means of potential gutters induced by an appropriate saw tooth design of p/sup +/ cathodes. The saw tooth period p/sub x/ (=anode pitch) is the parameter mainly determining the maximal capacity of confined charge. Up-to-now the confinement effect was experimentally observed with a saw tooth detector with p/sub x/=500 /spl mu/m. The final detector is intended to have an anode pitch of 250 /spl mu/m. The simulation of a saw tooth configuration with p/sub x/=250 /spl mu/m, p/sub y/=200 /spl mu/m, and /spl alpha/=60/spl deg/ showed that potential gutters with a depth of 80 mV will be produced assuming a drift field of 250 V/cm. We will give experimental evidence of these shallow charge confining potential gutters.