Abstract
With interest in the potential of optical fibres as the basis of next-generation thermoluminescence dosimeters (TLDs), the development of suitable forms of material and their fabrication has become a fast-growing endeavour. Present study focuses on three types of Ge-doped optical fibres with different structural arrangements and/or shapes, namely conventional cylindrical fibre, capillary fibre, and flat fibre, all fabricated using the same optical fibre preform. For doses from 0.5 to 8 Gy, obtained at electron and photon energies, standard thermoluminescence (TL) characteristics of the optical fibres have been the subject of detailed investigation. The results show that in collapsing the capillary fibre into a flat shape, the TL yield is increased by a factor of 5.5, the yield being also some 3.2 times greater than that of the conventional cylindrical fibre fabricated from the same perform. This suggests a means of production of suitably sensitive TLD for in-vivo dosimeter applications. Addressing the associated defects generating luminescence from each of the optical fibres, the study encompasses analysis of the TL glow curves, with computerized glow curve deconvolution (CGCD) and 2nd order kinetics.
Highlights
Optical fibres have been shown to be a potential candidate for such radiation dose sensors, with high spatial resolution, linear response over wide range of doses and acceptable sensitivity, the latter at a level that has become comparable with that of commercially available dosimeter sensors[12]
Together with our collaborators in radiation physics, we have reported on the performance of several tailor-made optical fibre TLDs25–31, initial observations pointing to the considerable potential of flat optical fibres[31,32] as a sensitive TL material for radiotherapy applications[26,27,29,31]
Since the TL response derives from the presence of defect centres[37], present results point to the presence of far greater numbers of defect centres in the flat fibre than in either the cylindrical or capillary fibre
Summary
Optical fibres have been shown to be a potential candidate for such radiation dose sensors, with high spatial resolution, linear response over wide range of doses and acceptable sensitivity, the latter at a level that has become comparable with that of commercially available dosimeter sensors[12]. A high sensitivity dosimeter would be extremely helpful in precision measurement of dose delivery, both to the tumour as well as in out-of-field measurements, such as potential neutron contributions from accelerators operated at high energies (≥10 MeV) becoming an important consideration[15]. Such performance can be expected to aid in obtaining an improved treatment outcome, in terms of enhanced tumour control and reduced post-radiation therapy complications[16]. To the best of our knowledge, this is the first report of its kind, comparing the response of these fibres with the popular phosphor-based LiF:Mg,Ti TLD, TLD-100
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