6–10 Jul 2026
University of the Western Cape
Africa/Johannesburg timezone
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Systematic Efficiency Characterisation of SiPM-Based Scintillator Trackers using Cosmic Muons

8 Jul 2026, 12:00
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

Mr Malefetsane Lenka (MSc Student)

Description

Cosmic muon trackers using plastic scintillators and Silicon Photomultipliers (SiPMs) are increasingly common in muon tomography applications due to their cost-effectiveness and robustness. In these systems, the high voltage (HV) applied to the SiPM directly influences the overvoltage, which determines key parameters such as gain, photon detection efficiency, and overall detector trigger efficiency.

This study presents a methodology for characterising detector performance using real hardware, providing experimental measurements of efficiency obtained with a physical detector setup. By performing systematic HV scans, we identify an efficiency turn-on followed by a plateau region. This behaviour was consistently observed and validated across two separate configurations: a stacked scintillator demonstration and a full muon hodoscope composed of planar perpendicular scintillator bars. We present this data to characterise the empirical relationship between bias voltage and detector response.

The results highlight that despite the high signal-to-noise ratio inherent in cosmic muon detection; with typical pulses exceeding 10 photoelectrons (p.e.) against a dark count rate of less than 5 p.e., empirical determination of the operating voltage remains a necessary step for consistent performance. This work demonstrates how defining the HV plateau allows for a selection of operating points that optimises overall detection efficiency while simultaneously minimising the impact of voltage and gain fluctuations on system stability.

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Author

Mr Malefetsane Lenka (MSc Student)

Presentation materials