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

Abstract

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 x 3.417 x 0.980) mm 3 and made of pure silica SiO 2 was selected for this research. The FF was annealed at 400 o 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 o C, maximum readout temperature of 400 o C and a heating rate of 30 o 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.

The thermoluminescence glow curve and the deconvoluted glow peak characteristics of erbium doped silica fiber exposed to 70–130 kVp x-rays

“…6, the activation energy E a of the deconvoluted glow peaks 2 and 4 show a significant decrease, by 30-60% with increasing dose. This result is in accord with the results for pure silica fiber following electron and photon irradiation, as measured by Alawiah et al (2013), the latter observing the dependency of E a on dose. Peaks 1, 3 and 5 were found to increase by 20-50% with increase in dose from 0.1 Gy to 0.7 Gy.…”

“…In all cases, the fibers were placed at the center of the field. Detailed description of the sample holder can be found in Alawiah et al (2013). Calibration of the x-ray beams was carried out using a calibrated cavity ionization chamber model PTW Farmer 30004 (Al electrode), the procedure following an internationally recognized calibration protocol (ICRU, 1976).…”

“…Recently, several researchers have studied the possibility of using silica (SiO 2 ) optical fibers as TL dosimeters (Alawiah et al, 2013;Bradley et al, 2012;Girard et al, 2006;Yusoff et al, 2005). In particular, they offer the ability to provide high spatial resolution, retaining the ability to integrate the total dose over a period of time.…”

The thermoluminescence characteristics and the glow curves of Thulium doped silica fiber exposed to 10MV photon and 21MeV electron radiation

“…Previous researchers had observed that the TL performance of an irradiated optical fibers is influenced by the type of fiber including the type of dopant material, diameter of the fiber core, the shape of fiber and the type of radiation (Hashim et al, 2010;Ramli et al, 2009;Abdul Rahman et al, 2011;Yaakob et al, 2011;Ong et al, 2009;Alawiah et al, 2013Alawiah et al, , 2015.…”

Enhancing the radiation dose detection sensitivity of optical fibres

“…An additional form of glass based dosimeter that has attracted considerable and growing attention are silica-based optical fibres , offering a range of advantages over other passive dosimeter types. These include high spatial resolution, by virtue of their very small size ( $ 125 mm) relative to many other forms of dosimeter, linear dose response in both the low and high dose regimes (Alawiah et al, 2013a(Alawiah et al, , 2013bGirard et al, 2013), capability for real time remote monitoring (Fernandez et al, 2008;O'Keeffe et al, 2007), lower cost (Espinosa et al, 2006) and relatively high dose sensitivity .…”