arXiv subjects
Publications and source records attributed to T. Saleem.
The detector group of Synchrotron SOLEIL is monitoring the performance of Energy-Resolved Detectors (EDX) and their associated electronics since last five years. A characterization procedure has been developed for this purpose and for Site Acceptance Tests (SATs) of new EDXs installed at beamlines. This manuscript presents the procedure, illustrating it with an example.
One of the main challenges in Environmental sciences is the identification and chemical evolution of polluting traces (e.g, cadmium or antimony) in soil, which requires long acquistion times for accurate measurements at synchrotron facilities. In this context, the potential of a new generation multi-element germanium detectors to identify traces at 0.1-1~ppm in a reasonable time has been studied using Allpix Squared framework. This code has been customized to include the three dimensional electric and weighting field maps generated by COMSOL Multiphysics software, and several features to model the sample environment at SOLEIL synchrotron and the signal response of a germanium detector equipped with a Digital Pulse Processor (DPP). The full simulation chain has been validated by experimental data from SAMBA beamline of SOLEIL synchrotron. This work presents a first estimation of the detection limit to cadmium traces in a soil sample for a future multi-element germanium detector, using this simulation chain.
X-rays spectroscopy experiments at synchrotron facilities were limited for many years by the maximum input-count rate and the signal-to-background ratio of germanium fluorescence detectors. These limitations are related to the germanium semiconductor device, the sensor configuration and its response to the incident X-ray flux at different energies. In order to understand and quantify such limitations, physics simulation of the detector response is a powerful tool to provide guidelines for designing, prototyping and improving detectors, as well as modelling experimental environments, which reduces time and cost of development. For this purpose, a first complete and operational simulation chain based on Allpix Squared framework is presented, customized to multi-element germanium detectors and combined with three-dimensional simulations of the electric field and the weighting potential, based on COMSOL Multiphysics. Based on this simulation chain, a quantification of charge sharing effect as well as signal-to-background ratio at different beam energies has been made for a germanium detector equipped with and without collimator. In addition, two experimental measurements have been performed on the SAMBA beamline at SOLEIL synchrotron. The experimental data were used to set up the full simulation chain and good agreements have been observed between data and simulation.