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

Recently it has been experimentally shown that saw tooth shaped p ⁺ 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⁺ cathodes. The saw tooth period p_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_x=500 μm. The final detector is intended to have an anode pitch of 250 μm. The simulation of a saw tooth configuration with p_x=250 μm, p_y=200 μm, and α=60° 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