6–10 Jul 2026
University of the Western Cape
Africa/Johannesburg timezone
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GEANT4 Study on Suitability of Diamond-Coated LPG Sensors

7 Jul 2026, 12:00
20m
Lecture Hall DL3 (University of the Western Cape)

Lecture Hall DL3

University of the Western Cape

Oral Presentation Track F - Applied Physics Applied Physics

Speakers

Abdool Sattar Cassim (Unioversity of Johannesburg) Timothy Brooks (University of Johannesburg)

Description

Long Period Grating (LPG) fiber optic sensors are widely used for environmental and chemical sensing due to their high sensitivity to refractive index changes; however, their deployment in high-radiation environments requires a thorough understanding of radiation–matter interactions within the sensor structure. In this study, a simulation-based investigation is conducted using Geant4 to evaluate the suitability of diamond-coated LPG sensors for operation in radiation-rich environments. A detailed geometrical model of an LPG sensor is implemented, incorporating the silica core, cladding, and a nanocrystalline diamond (NCD) coating layer. Proton irradiation conditions representative of facilities such as the CERN IRRAD facility are simulated to quantify energy deposition, dose distribution, and secondary particle generation within the sensor. Particular attention is given to the grating region, where radiation-induced changes directly influence sensor performance. The simulation results are used to compare coated and uncoated configurations, assessing the impact of the diamond layer on dose attenuation, energy redistribution, and interface effects between diamond and silica. Key dosimetric quantities, including absorbed dose and linear energy transfer, are analyzed to infer potential implications for radiation-induced refractive index changes and long-term sensor stability. The findings indicate that irradiated diamond coatings can modify the local microstructure environment of the sensing region while offering potential advantages in radiation hardness and thermal stability. This study provides a physics-based framework for evaluating advanced coating strategies in fiber optic sensors and supports the development of robust LPG-based sensing platforms for applications in high-energy physics, nuclear environments, and space systems.

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Author

Abdool Sattar Cassim (Unioversity of Johannesburg)

Co-authors

Prof. Daniel Madyira (University of Johannesburg) Emmanuel Igumbor (University of Johannesburg) Loan Truong (University Of Johannesburg) Simon Connell (University of Johannesburg) Timothy Brooks (University of Johannesburg)

Presentation materials