An ultra-high dose of electron radiation response of Germanium Flat Fiber and TLD-100

The thermoluminescence (TL) response of Germanium Flat Fiber (GFF) and TLD-100 irradiated with 2.5 MeV electrons for the doses up to 1 MGy were studied and compared. The aim was to evaluate the TL supralinearity response at an ultra-high dose (UHD) range and to investigate the change in kinetic parameters of the glow peaks, as the doses increases up to 1 MGy. It is found that the critical dose limit (CDL) of GFF is 5 times higher as compared to TLD-100. CDL is determined by the dose at the maximum supralinearity, f(D)max. It is also found that annealing the TLD-100 and GFF with temperature more than 400 °C is required to reset it back to its original condition, following radiation doses up to 1 MGy. It is also noticed the strange behavior of Peak 4 (TLD-100), which tends to be invisible at the lower dose (<10 kGy) and starts to be appeared at the critical dose limit of 10 kGy. This result might be an important clue to understand the behavior of TLD-100 at extremely high dose range. For both samples, it is observed that the TL intensity is not saturated within the UHD range studied

Dose response reproducibility using electron and photon beams.

<p>Dose response reproducibility using electron and photon beams.</p

The mean sensitivity of the studied fibres.

<p>The mean sensitivity of the studied fibres.</p

TL sensitivity for different core size and Ge concentration detectors.

<p>TL sensitivity of detectors with respect to: (a) Core diameter and; (b) Ge concentration.</p

Comparison of dosimetric response for PCF-collapsed cylindrical and flat fibres.

<p>Figure shows the dosimetric response for PCF-collapsed.10% Ge-doped (33 & 42 μm core diameter cylindrical fibres) and flat-fibres (6 & 10% Ge-doped), irradiated with 6 MV photons for doses from 25–550 cGy.</p

Comparison of SD values of clinically used dosimeters with the studied silica based dosimeter.

<p>Comparison of SD values of clinically used dosimeters with the studied silica based dosimeter.</p

The normalized TL Yield of angular dependency at 0 degree.

<p>The fig indicate that the fibre optic detectors have minimal (<1%) angular dependency For (a) 42 μm core sizes, and (b) PCF-collapsed fibres.</p