Gepta-EX: A multi-channel germanium detector for X-ray absorption fine structure

Published

May 21, 2026

Author(s)

Bruce Ravel, Abdul Rumaiz, Francesca Capocasa, GIOVANNI PINAROLI, Thomas Krings, David Siddons

Abstract

We report on the development, fabrication, and performance evaluation of Gepta-EX, a compact multi-channel high-purity germanium (HPGe) detector system designed for fluorescence-mode X-ray Absorption Spectroscopy (XAS) at high photon energies. Traditional silicon-based detectors suffer from poor efficiency above ∼20 keV, while most high-Z materials such as Cadmium Telluride (CdTe), Cadmium Zinc Telluride (CZT), and Gallium Arsenide (GaAs) have focused predominantly on imaging applications with limited spectroscopic resolution. In contrast, germanium combines excellent stopping power with superior intrinsic energy resolution due to its low Fano factor and favorable charge transport properties, making it ideal for high-resolution spectroscopy in the 15–100 keV range. The Gepta-EX system features a monolithic 7-channel HPGe pixel array integrated with low-noise CUBE charge-sensitive preamplifiers, housed within a thermally isolated compact cryostat operating near 90K. The detector achieves energy resolutions of 218 eV at 5.9 keV (from 55Fe) and 373 eV at 59.5 keV (from 241Am), with uniform performance across all channels. By eliminating the escape peak interference commonly associated with silicon detectors and providing stable, high-resolution performance, Gepta-EX represents a powerful tool for high-energy X-ray spectroscopy.

Citation

Journal of Synchrotron Radiation

Volume

33

Issue

4

Pub Type

Journals

Download Paper

https://doi.org/10.1107/S1600577526004261

Local Download

Keywords

X-ray detectors, X-ray absorption spectroscopy, Germanium

Citation

Ravel, B. , Rumaiz, A. , Capocasa, F. , PINAROLI, G. , Krings, T. and Siddons, D. (2026), Gepta-EX: A multi-channel germanium detector for X-ray absorption fine structure, Journal of Synchrotron Radiation, [online], https://doi.org/10.1107/S1600577526004261, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=961000 (Accessed May 30, 2026)

Additional citation formats