| Summary: | Present investigations concern germanium (Ge) doped (2.3 and 6.0 mol%) silica preforms
fabricated into cylindrical- and flat-shaped fibre radiation dosimeters. When subjected to
150-MeV proton beam irradiation, the fibres are observed to produce sensitive dose
response. The fibres are fabricated via a modified chemical vapour dopant deposition
technique and subsequent pulling process. Prior to irradiation, a thermal annealing
process was carried out to erase any pre-irradiation signals potentially existing in the
samples. For radiation dose in the range from 1 up to 10 Gy, these optical fibres exhibit an
excellent linear relationship, offering coefficients of determination (R²) better than 0.99,
suggesting reliable calibration and utilisation. The general structure of
thermoluminescence (TL) glow curve is presented as a broad peak, differing from that of
the phosphor-based TLD-100 dosimeter. The maximum in the TL glow curve peak
manifests at a temperature within the readout range 231- to 350 °C. The relatively high
glow-peak temperatures allow the fabricated Ge-doped optical fibres to be measured
between room- and high-temperature conditions. In terms of shape, the TL glow curve
remains unchanged at different irradiation dose within the investigated range of interest
(1 to 5 Gy). The TL properties studied herein provide an important advance in
understanding the TL mechanism in the fabricated Ge-doped silica fibres, shown to be
viable for use in proton beam dosimetry.
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