6–10 Jul 2026
University of the Western Cape
Africa/Johannesburg timezone
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Extracting Radioisotope Lifetimes from a 100 MeV Gamma Irradiation Experiment Using HPGe Spectroscopy

8 Jul 2026, 15:10
20m
Lecture Hall GH2 (University of the Western Cape)

Lecture Hall GH2

University of the Western Cape

Oral Presentation Track B - Nuclear, Particle and Radiation Physics Nuclear, Particle and Radiation Physics -1

Speaker

Thendo Emmanuel Nemakhavhani (UNIVERSITY OF JOHANNESBURG)

Description

The Mineral Positron Emission Tomography (MinPET) technology enables a three-dimensional imaging of diamonds within a kimberlite host rock by reconstructing coincidence 511 keV gamma rays from $^{11}$C. These are produced via the $^{12}$C($\gamma$, n)$^{11}$C bremsstrahlung reaction during irradiation. However, the activation process also induces radioactivity in the surrounding kimberlite matrix, generating a mixed field of background isotopes that must be understood for radiological safety and signal discrimination. To investigate this, a Full-Dress Rehearsal (FDR) experiment was conducted at the ASTRID2 accelerator facility at {\AA}rhusrhus University, Denmark, using a 100 MeV electron beam to replicate the MinPET activation stage. High-purity germanium (HPGe) spectroscopy was employed to measure gamma emissions from irradiated samples. This study focuses on extracting the lifetimes of the resulting radioisotopes from the measured energy spectra. The experimentally determined lifetimes are compared with reference values from the Table of Radiation Isotopes. The results show good agreement between measured and tabulated lifetimes across all identified isotopes. These findings enable the construction of a comprehensive inventory of activation products and allow for clear differentiation from Naturally Occurring Radioactive Materials (NORM). The validated lifetime data contribute to a long-term radiological safety assessment, confirming that the isotopic signatures produced during MinPET operation are well characterized and consistent with established nuclear data.

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Author

Thendo Emmanuel Nemakhavhani (UNIVERSITY OF JOHANNESBURG)

Co-authors

Prof. Charis Harley (UNIVERSITY OF JOHANNESBURG) Dr Martin Cook Simon Connell (University of Johannesburg) Mr TIEGO MALESELA MPAI (UNIVERSITY OF JOHANNESBURG) Mr Timothy Brooks (UNIVERSITY OF JOHANNESBURG) Mr nick connell (UNIVERSITY OF JOHANNESBURG)

Presentation materials