Thermoluminescence glow curve study of beta irradiated germanium doped core fibre with different dopant concentrations

Abstract

This paper reports the assessment of commercial Ge-doped fibres as a potential dosimeter. The thermoluminescence response was measured for 4 fibre types: commercial multi-mode germanium doped core fibres at 4% and 6% weight Ge doping; single mode fibre with a 17% Ge and 1% B (GeB) doped core; and undoped silica fibre. The fibres were subjected to beta irradiation (90Sr/90Y), heated from room temperature to 400 °C. The 6% Ge doped fibre exhibited sensitivity of 7.7 ± 0.2 counts⋅mm−1⋅Gy−1⋅μm−2, greater than the 4% Ge-doped and GeB fibres by factors of 9.2 and 1.3 respectively. All the core-doped fibres (Ge, GeB) showed a high linear response across the dose range 1–10 Gy (R2 = 0.99). Increasing the Ge concentration from 4 to 17% lowered the temperature of the glow curve peak from 317 °C to 248 °C. The glow curve for both Ge doped core fibres were analysed using a computerised glow curve deconvolution (CGCD) in TolAnal software. When including Ge dopants, the estimated trap depth for five sub-peaks in the Ge doped fibre was reported between 0.6 and 1.54 eV.