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arXiv · 2504.03462

Investigating irradiation effects and space charge sign inversion in n-type Low Gain Avalanche Detectors

Veronika Kraus·Margarita Biveinytė·Marcos Fernandez Garcia·Salvador Hidalgo·Michael Moll·Jairo Villegas·Moritz Wiehe
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Abstract

Low Gain Avalanche Detectors built on n-type substrate (nLGADs) have been developed by IMB-CNM to enhance the detection of low-penetrating particles, with a wide range of applications from medicine, industry to synergies with developments for high-energy physics (HEP). In this work, irradiation effects on nLGADs were investigated through proton irradiation at the CERN PS-IRRAD facility up to proton fluences of $10^{14}\,\mathrm{cm}^{-2}$. Electrical characterization before and after irradiation reveals space charge sign inversion of the n-type bulk, leading to significant modifications in the depletion behavior and electric field distribution. Utilizing UV TCT and TPA-TCT measurements, the impact of irradiation on the electric fields and the gain are studied in more detail, confirming a change of sensor depletion and a reduced electric field in the gain layer. The results suggest that donor removal in nLGADs is stronger pronounced already at lower fluences compared to acceptor removal in traditional p-type LGADs. These findings provide not only first insights into the effects of irradiation on nLGADs but also contribute to the development of methods to quantify the donor removal.

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Veronika Kraus, Margarita Biveinytė, Marcos Fernandez Garcia, Salvador Hidalgo, Michael Moll, Jairo Villegas, Moritz Wiehe. 2025-07-14. Investigating irradiation effects and space charge sign inversion in n-type Low Gain Avalanche Detectors. https://arxiv.org/abs/2504.03462

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