Begum Mahfuza, Rahman A K M Mizanur, Abdul-Rashid H A, Yusoff Z, Mat Nawi Siti Nurasiah, Khandaker Mayeen Uddin, Bradley D A
Health Physics & Radioactive Waste Management Unit, Institute of Nuclear Science and Technology, Atomic Energy Research Establishment, Bangladesh Atomic Energy Commission, Ganakbari, Savar, Dhaka, Bangladesh.
Health Physics Division, Atomic Energy Centre, Bangladesh Atomic Energy Commission, 4 Kazi Nazrul Islam Avenue, Shahbag, Dhaka, 1000, Bangladesh.
Appl Radiat Isot. 2021 Aug;174:109771. doi: 10.1016/j.apradiso.2021.109771. Epub 2021 May 21.
Present study concerns the key thermoluminescence (TL) properties of photonic crystal fibres (PCFs), seeking development of alternatively structured TL materials that are able to offer a advantages over existing passive dosimeters. In terms of their internal structure and light guiding properties the PCFs, collapsed and structured, differ significantly from that of conventional optical fibres. To investigate the dosimetric parameters of the PCFs use was made of a linear accelerator producing a 6 MV photon beam, delivering doses ranging from 0.5 Gy to 8 Gy. The parameters studied included TL response, linearity index, glow curves, relative sensitivity and TL signal fading, the results being compared against those obtained using TLD-100 chips. At 4 Gy photon dose the Ge-doped collapsed PCFs were found to provide a response 27 × that of structured PCF, also giving a TL yield similar to that of standard TLD-100 chips. Over post-irradiation periods of 15 and 30 days collapsed PCF TL signal fading were 8% and 17% respectively, with corresponding values of 37% and 64% for the structured PCF. Trapping parameters including the order of kinetics (b), activation energy (E) and frequency factor (s) were assessed with Chen's peak shape method. Lifetime of trapping centre was found to be (2.36 E+03) s and (9.03 E +01) s regarding the collapsed and structured PCF respectively with 6 Gy of photon beam. For the Ge-doped collapsed PCF, the high TL yield, sensitivity and low fading provide the basis of a highly promising system of TLD for radiotherapy applications.
本研究关注光子晶体光纤（PCF）的关键热释光（TL）特性，旨在开发具有替代结构的TL材料，使其比现有的被动剂量计更具优势。就其内部结构和光导特性而言，塌陷型和结构化的PCF与传统光纤有显著差异。为了研究PCF的剂量学参数，使用了一台产生6 MV光子束的直线加速器，提供0.5 Gy至8 Gy的剂量。研究的参数包括TL响应、线性指数、发光曲线、相对灵敏度和TL信号衰减，并将结果与使用TLD-100芯片获得的结果进行比较。在4 Gy光子剂量下，发现掺锗塌陷型PCF的响应是结构化PCF的27倍，其TL产额也与标准TLD-100芯片相似。在辐照后15天和30天的时间段内，塌陷型PCF的TL信号衰减分别为8%和17%，结构化PCF的相应值为37%和64%。使用陈的峰形方法评估了包括动力学级数（b）、活化能（E）和频率因子（s）在内的俘获参数。对于6 Gy的光子束，塌陷型和结构化PCF的俘获中心寿命分别为(2.36 E+03) s和(9.03 E +01) s。对于掺锗塌陷型PCF，高TL产额、灵敏度和低衰减为放疗应用中极具前景的TLD系统提供了基础。
