Simulation of charge transport in pixelated CdTe.
The Voxel Imaging PET (VIP) Pathfinder project intends to show the advantages of using pixelated semiconductor technology for nuclear medicine applications to achieve an improved image reconstruction without efficiency loss. It proposes designs for Positron Emission Tomography (PET), Positron Emission Mammography (PEM) and Compton gamma camera detectors with a large number of signal channels (of the order of 106). The design is based on the use of a pixelated CdTe Schottky detector to have optimal energy and spatial resolution. An individual read-out channel is dedicated for each detector voxel of size 1 × 1 × 2 mm3using an application-specific integrated circuit (ASIC) which the VIP project has designed, developed and is currently evaluating experimentally. The behaviour of the signal charge carriers in CdTe should be well understood because it has an impact on the performance of the readout channels. For this purpose the Finite Element Method (FEM) Multiphysics COMSOL software package has been used to simulate the behaviour of signal charge carriers in CdTe and extract values for the expected charge sharing depending on the impact point and bias voltage. The results on charge sharing obtained with COMSOL are combined with GAMOS, a Geant based particle tracking Monte Carlo software package, to get a full evaluation of the amount of charge sharing in pixelated CdTe for different gamma impact points.
Institut de Física d'Altes Energies (IFAE), Edifici Cn, Universitat Autónoma de Barcelona (UAB), E-08193 Bellaterra, Spain.
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Kolstein
Institut de Física d'Altes Energies (IFAE), Edifici Cn, Universitat Autónoma de Barcelona (UAB), E-08193 Bellaterra, Spain.
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Ariño
Institut de Física d'Altes Energies (IFAE), Edifici Cn, Universitat Autónoma de Barcelona (UAB), E-08193 Bellaterra, Spain.
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Chmeissani
Institut de Física d'Altes Energies (IFAE), Edifici Cn, Universitat Autónoma de Barcelona (UAB), E-08193 Bellaterra, Spain.
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De Lorenzo
Charge induction; Charge transport and multiplication in solid media; Detector modelling and simulations II (electric fields, charge transport, multiplication and induction, pulse formation, electron emission, etc); Solid state detectors