Thermoluminescence characteristics of flat optical fiber in radiation dosimetry under different electron irradiation conditions

摘要

The thermoluminescence (TL) provided by flat optical fibers (FF) have been proposed as the basis for a novel radiation sensor, for use in medical dosimetry for both diagnostic and radiotherapy applications. A flat optical fiber with nominal dimensions of (3.226 × 3.417 × 0.980) mm~3 and made of pure silica SiO_2 was selected for this research. The FF was annealed at 400°C for 1 h before being irradiated. Using a linear accelerator (LINAC), delivering doses in the range 2.0-10.0 Gy, the kinetic parameters and dosimetric glow curve representing TL response of the FF were studied with respect to electron irradiation of 6 MeV, 15 MeV and 21 MeV. The TL response was read out using a TLD reader Harshaw Model 3500. The Time-Temperature-Profile (TTP) of the reader used includes; initial preheat temperature of 80°C, maximum readout temperature of 400°C and a heating rate of 30°Cs~(-1). The proposed FF shows excellent linear radiation response behavior within the clinical relevant dose range for all of these energies, good reproducibility, independence of radiation energy, independence of dose rate and exhibits a very low thermal fading. From these results, the proposed FF can be used as radiation dosimeter and favorably compares with the widely used LiF:MgTi dosimeter, for application in medical radiotherapy application.