Speaker
Description
X-ray Absorption Fine Structure spectroscopy (XAFS) is crucial to investigate the electronic and atomic structure of different kinds of samples [1]. The efficacy of this technique, widely deployed at synchrotron facilities, is constrained by the performance limitations of the current generation of Ge detectors. To perform XAFS measurements, energy-resolving detectors capable of handling high count rates are essential [2]. While efforts have been focused on developing arrays of Silicon Drift Detectors (SDDs), less attention has been given to enhancing the performance of High Purity Germanium (HPGe) detectors for synchrotron applications. HPGe detectors offer better detection efficiency at high energies compared to SDDs.
To address this, a detector consortium under the European project LEAPS-INNOV [3] launched an ambitious R&D program aimed at developing a new generation of multi-element monolithic HPGe detectors specifically tailored for X-ray detection [4]. Two detector prototypes are currently under development and are anticipated to undergo characterization in early summer 2024. Simulations of the detector prototypes have been conducted to optimize the detector performance. Each prototype is equipped with a 10-element monolithic HPGe sensor, one with a 5 mm2 area pixels and another with 20 mm2 area pixels. Additionally, a novel electronic chain has been engineered, allowing crosstalk and charge-sharing correction, and enabling the processing of higher count rates ranging from 20 kcps/mm2 up to 250 kcps/mm2, while preserving reasonable energy resolution and minimizing dead time within the required energy range.
This work presents a comprehensive overview of the detector prototypes, encompassing mechanical design details, HPGe sensor specifications, electronic configurations, and their individual performance. Furthermore, results from simulations aimed at optimizing the detector's functionality are presented and analysed. Currently, the prototypes are undergoing assembly, with forthcoming laboratory and beamline tests planned before Summer 2024 to evaluate their performance. First results of the detector characterization will also be reported.
[1] G. Bunker, ”Introduction to XAFS: A Practical Guide to X-Ray Absorption Fine Structure Spectroscopy”. Cambridge, U.K., Cambridge Univ. Press, 2010.
[2] N. Tartoni, et al., ”Hexagonal Pad Multichannel Ge X-Ray Spectroscopy Detector Demonstrator: Comprehensive Characterization,” in IEEE Transactions on Nuclear Science, vol. 67, no. 8, pp. 1952-1961, Aug. 2020.
[3] LEAPS pilot to foster open innovation for accelerator-based light sources in Europe, European Union’s Horizon 2020, Grant Agreement No. 101004728.
[4] F. Orsini, et al., “XAFS-DET: a new high throughout X-ray spectroscopy detector system developed for synchrotron applications”, Nucl. Instrum. Meth. A, Volume 1045, 2023, 167600, https://doi.org/10.1016/j.nima.2022.167600.
| I plan to submit also conference proceedings | Yes |
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