Signal formation in a CdZnTe imaging detector with coplanar pixel and control electrodes

In order to gain insight on a proposed CZT imaging device with orthogonal coplanar anodes currently under development, measurements have been made on an available commercial device with pixels and control electrodes. Charge signals induced on both the pixel and control electrodes by alphas incident at two positions on the cathode side are measured and compared with model predictions. Signals produced by γ-rays are also discussed. Measurements and simulations are found to be in reasonably good agreement. It is concluded that the proposed anode geometry might exhibit excellent energy resolution and good position resolution in two dimensions as well as some position information along the depth dimension.