Soft X-Ray Detection Down to the Nitrogen K-Edge Using a Pixelated iLGAD Sensor
Abstract
Hybrid pixel detectors represent the state-of-the-art technology for hard X-ray experiments at synchrotron light sources and free-electron lasers, owing to their high frame rates, extended dynamic range, and scalable detection areas. However, their application in the soft X-ray regime remains bottlenecked by the challenge of developing a sensor that can achieve high quantum efficiency and an sufficient signal-to-noise ratio at low photon energies. Here, we present inverse low-gain avalanche diode (iLGAD) sensors integrated with a thin entrance window, demonstrating single-photon resolution down to 390 eV (below the Nitrogen K-edge) with a signal-to-noise ratio of 5. Two gain layer designs, standard gain layer and shallow gain layer, were systematically investigated to evaluate their spectral response as a function of photon energy and operating temperature. A double-peak feature is observed in the energy spectrum, arising from the dependence of charge multiplication on photon absorption depth. Furthermore, a phenomenological spectral fitting model was established, enabling the quantitative extraction of the effective n+ layer thickness and gain layer depth. Beyond providing a fundamental understanding of iLGAD charge multiplication mechanisms and characterization results in the soft X-ray regime, these findings lay the foundation for developing large-area, high-frame-rate hybrid pixel detectors for soft X-ray. This advancement directly benefits soft X-ray photon science applications, including high-resolution ptychography, spectroscopy, and resonant scattering at synchrotron and FEL beamlines.
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BibTeX
@misc{li2026soft,
title = {{Soft X-Ray Detection Down to the Nitrogen K-Edge Using a Pixelated iLGAD Sensor}},
author = {Shuqi Li and Anna Bergamaschi and Ashish Bisht and Maurizio Boscardin and Martin Brückner and Maria Carulla and Tomáš Celko and Roberto Dinapoli and Simon Ebner and Simone Emiliani and Khalil Ferjaoui and Erik Fröjdh and Viveka Gautam and Dominic Greiffenberg and Shqipe Hasanaj and Viktoria Hinger and Marius Hürst and Vadym Kedych and Thomas King and Antonio Liguori and Carlos Lopez-Cuenca and Leonid Lunin and Alice Mazzoleni and Davide Mezza and Scharon Moses and Konstantinos Moustakas and Aldo Mozzanica and Jonathan Mulvey and Martin Müller and Giovanni Paternoster and Christian Ruder and Bernd Schmitt and Saverio Silletta and Dhanya Thattil and Matteo Centis Vignali and Xiangyu Xie and Jiaguo Zhang and Sinuo Zhang},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.42064},
eprint = {2610.42064},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.42064},
}
RIS
TY - UNPB
TI - Soft X-Ray Detection Down to the Nitrogen K-Edge Using a Pixelated iLGAD Sensor
AU - Shuqi Li
AU - Anna Bergamaschi
AU - Ashish Bisht
AU - Maurizio Boscardin
AU - Martin Brückner
AU - Maria Carulla
AU - Tomáš Celko
AU - Roberto Dinapoli
AU - Simon Ebner
AU - Simone Emiliani
AU - Khalil Ferjaoui
AU - Erik Fröjdh
AU - Viveka Gautam
AU - Dominic Greiffenberg
AU - Shqipe Hasanaj
AU - Viktoria Hinger
AU - Marius Hürst
AU - Vadym Kedych
AU - Thomas King
AU - Antonio Liguori
AU - Carlos Lopez-Cuenca
AU - Leonid Lunin
AU - Alice Mazzoleni
AU - Davide Mezza
AU - Scharon Moses
AU - Konstantinos Moustakas
AU - Aldo Mozzanica
AU - Jonathan Mulvey
AU - Martin Müller
AU - Giovanni Paternoster
AU - Christian Ruder
AU - Bernd Schmitt
AU - Saverio Silletta
AU - Dhanya Thattil
AU - Matteo Centis Vignali
AU - Xiangyu Xie
AU - Jiaguo Zhang
AU - Sinuo Zhang
PY - 2026
DA - 2026/10/30
PB - arXiv
DO - 10.48550/arxiv.2610.42064
UR - https://arxiv.org/abs/2610.42064
AB - Hybrid pixel detectors represent the state-of-the-art technology for hard X-ray experiments at synchrotron light sources and free-electron lasers, owing to their high frame rates, extended dynamic range, and scalable detection areas. However, their application in the soft X-ray regime remains bottlenecked by the challenge of developing a sensor that can achieve high quantum efficiency and an sufficient signal-to-noise ratio at low photon energies. Here, we present inverse low-gain avalanche diode (iLGAD) sensors integrated with a thin entrance window, demonstrating single-photon resolution down to 390 eV (below the Nitrogen K-edge) with a signal-to-noise ratio of 5. Two gain layer designs, standard gain layer and shallow gain layer, were systematically investigated to evaluate their spectral response as a function of photon energy and operating temperature. A double-peak feature is observed in the energy spectrum, arising from the dependence of charge multiplication on photon absorption depth. Furthermore, a phenomenological spectral fitting model was established, enabling the quantitative extraction of the effective n^+ layer thickness and gain layer depth. Beyond providing a fundamental understanding of iLGAD charge multiplication mechanisms and characterization results in the soft X-ray regime, these findings lay the foundation for developing large-area, high-frame-rate hybrid pixel detectors for soft X-ray. This advancement directly benefits soft X-ray photon science applications, including high-resolution ptychography, spectroscopy, and resonant scattering at synchrotron and FEL beamlines.
ER -