The assessment of tailor-made optical fibre subjected to ionizing radiation

Abstract

The dosimetric properties of thermoluminescence (TL) dosimeter such as dose response, linearity, sensitivity, fading, minimum detectable dose (MDD), glow curve and reproducibility of optical fibres in comparison with TLD-100 (rod types) have been investigated. The samples used were Dummy Flat Fibre (DFF), Flat Fibre (FF), Photonic Crystal Fibre (PCF), Multi Photonic Crystal Fibre (MPCF) of 2 mm and 220 µm diameter, Photosensitive Flat Fibre (PFF), Single Mode Optical Fibre (SMF), Germanium - doped (Ge), Erbium - doped (Er) and Aluminum doped Thulium (Al: Tm). The TL samples were placed in solid phantom and irradiated with 6, 9 and 12 MeV electrons beam with dose ranging from 1.0 Gy to 4.0 Gy by using linear accelerator (LINAC) machine. Investigations were also conducted for X - rays with mean energies of 30, 60 and 70 kV, and gamma rays (60Co) from 1.0 mGy up to 24.0 Gy. The glow curves were observed between 155 °C to 287 °C. The results of TL dosimeter subjected to 6, 9 and 12 MeV electrons clearly showed that PFF was superior in terms of TL response and sensitivity. This was followed by Ge, DFF, TLD-100, FF, PCF, Er, Al: Tm, MPCF 2 mm and MPCF 220 µm. For X-ray irradiation, the SMF showed 10 and 8 times more sensitive than TLD-100. The MDD obtained from optical fibres subjected to electron irradiation were between 0.53- 0.60 mGy for PFF, 0.78-0.81 mGy for TLD-100, 1.00-1.26 mGy for Ge and 1.44-1.64 mGy for DFF. The results showed that PFF and SMF have great potential to be considered as a radiation dosimeter.