超薄型丙氨酸／ESR剂量计特性的研究

报道了自制的丙氨酸／ＥＳＲ剂量计的研究结果。该系统包括４部分：丙氨酸探测器的制备；照射设备；ＥＳＲ波谱的测读和刻度方法。研究了这种超薄（０．５ｍｍ）型剂量计的一般特性和剂量学特性：包括，样品密度的均匀性；最小可达厚度；可探测下限；方法的重复性；线性范围；分散性等。为了刻度电子剂量，利用一个经标准装置外推电离室刻度过的旋转式９０°Ｓｒ＋９０Ｙ面源构成的参考辐射场，大大提高了均匀性、稳定性、重复性以及量值的可溯源性。利用精密温、湿度长时间自动控制系统和６０Ｃｏ板源辐射场，在严格控制实验中的有影响因素和有关参数的条件下，对丙氨酸／电子自旋共振剂量计的灵敏度与照射温度的关系进行了系统地研究，得到了在辐照剂量为１．４×１０３、１．４×１０４、和１．０×１０５Ｇｙ、照射温度在１０一７０℃时灵敏度的温度系数，以及平均温度系数，其值为０．２４％℃－１。

DEVELOPMENT OF ULTRATHIN SECTION ALANINE/ESR DOSIMETERS

The present workhas dealt with the research on the alanine/ESR dosimeters. They includefour major results,i.e. preparation of alanine detectors,irradiation,evaluation by an ESR spec-trometer and the calibration method.The design of modelling tools and experimental capsules isdescribed. The physical,chemical and dosimetric properties of the free radical dosimeters,such asthe homogeneity of the sample density,smallest thickness,lowest detectable limit,repeatabilityof the method,reproducibility resulted in directivity and location in resonance cavity,linearity re-gions as well as relative scattering of the response to identical doses are summarized. With regard to atomic composition,effective atomic number and mass density it is approxi-mate to tissue equivalent.So that such a dosimeter may be considered a tissue equivalent( TE)chamber. These properties combining a high yield of free radicals after irradiation with a very lowprior-dose corresponding with a zero signal and high precision in the measurement by an electronspin resonance spectrometer make it a useful dosimeter for both routine use and transfer dosimeter.