Title: Mapping sensitivity of a single crystal CVD diamond detector using a focused X-ray beam

Authors: Mohamed A.E. Abdel-Rahman; Wedad R. Alharbi; Atef El-Taher; Annika Lohstroh

Addresses: Nuclear Engineering Department, Military Technical College, Kobry El-Kobba, Cairo, Egypt; Department of Physics, University of Surrey, Guildford, Surrey, UK ' Physics Department, College of Science, University of Jeddah, Jeddah, Makkah, Saudi Arabia ' Physics Department, Faculty of Science, Al-Azhar University, Assiut Branch, Assiut, Egypt ' Department of Physics, University of Surrey, Guildford, Surrey, UK

Abstract: This study investigates the mapping sensitivity of a low-purity single crystal diamond detector (VS-Ti/Au) using a focused X-ray beam from an X-ray tube. It examines how beam size, scanning step, bias polarity, annealing, and X-ray dose rate affect the photocurrent response and nitrogen-related features within the crystal. Temporal photocurrent behaviour was analysed through pulse shapes recorded under varied conditions. The detector, fabricated by Chemical Vapour Deposition, was selected for its internal nitrogen lines and substrate interface visible in X-ray maps. Two independent methods - fluorescent screen imaging and silicon diode edge scanning - were used to determine the X-ray spot size, both showing consistent trends with dose rate, though the diode method gave slightly larger values. The results provide key insights into the spatial and temporal behaviour of diamond detectors, aiding optimisation for high-resolution radiation detection.

Keywords: sensitivity mapping; radiation dosimetry; focused X-ray; CVD diamond; silicon PIN diode.

DOI: 10.1504/IJNEST.2025.150739

International Journal of Nuclear Energy Science and Technology, 2025 Vol.18 No.2, pp.108 - 127

Accepted: 28 Aug 2025
Published online: 22 Dec 2025 *

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