MGS stands for Multi Geometry Simulation. It has two main purposes :
Characterisation of any shape of Germanium and Silicium detectors
Simulation of charge signal at the contacts and charge carrier trajectories
By using fixed grid geometry, any new kind of shape (planar, cylindrical, with or without segments or stripes) can be added in a very short time.
The aim of this work is to provide a comprehensive methodology for the full characterization of HPGe detectors, with no restriction to a particular geometry. The multi geometry simulation (MGS) code is structured in a progressive way, starting from the definition of the crystal geometry to characterize, up to the generation of the expected pulse shapes at the contacts :
Calculation of the electric field from the potential computed with Poisson equation
Implementation of charge carrier transport in a semi-conducting medium, comprising trapping effects
Weighting potentials and weighting fields resolution
Trajectories of charge carriers for arbitrary interaction points
Application of the Ramo theorem providing the resulting pulse shape on each electrode
Scanning of selected areas in the crystal. Computed currents are stored either in ASCII or in binary format
Simulation of the charge-collection efficiency
A set of customisable templates representing standard detectors is included and made accessible through a graphical user interface. This allows the interactive tuning of parameters such as anisotropy angles and interaction position. The program is available as a stand-alone graphical application running under Windows / Linux PC.
Matlab (MathWorks) is the selected environment to develop our algorithms. It is a matrix-based simulation language, as well as an environment intended for numerical and symbolic computations.
Development team : Patrice Médina, Cayetano Santos and Camille Parisel