Device simulation and optimization of laterally-contacted-unipolar-nuclear detector

Unipolar gamma-ray detectors offer the possibility of enhanced energy resolution and detection sensitivity over the conventional planar detectors. However, these detectors are difficult to understand and to fabricate, due to their three-dimensional geometry and multiple electrodes. Computer simulation offers a powerful way to design and to optimize these detectors, by giving the internal electric fields, weighting potentials, and spatially resolved detector responses. Simulation and optimization of an unipolar gamma-ray detector called laterally-contacted-unipolar-nuclear detector (LUND) are shown. For 662 keV γ-rays from a 137Cs source, the simulation and optimization of LUND resulted in improvement in the energy resolution from 1.6% to 1.3% and improvement in the active detector volume from 4% to 38% of the total detector volume.