Gray微束定位辐射准确性的研究

Studies of Localization Irradiation Accuracy of Gray Laboratory Microbeam

对Gray微束装置的定位辐射准确度进行了全面的实验研究。微束定位辐射的能力表现在辐射点的准确度高低和离子分布区域的大小二个方面。辐射点的准确度取决于样品架的回访精度和图像处理系统的样品识别准确度 ;离子的分布取决于瞄准器的结构。通过对 3 5MeV的3 He2 + 离子辐射后CR39样品上留下束斑的大小和中心位置的分析 ,得到了有关Gray微束定位辐射能力的数据。在辐射点准确度方面 ,仅由样品架参与工作时 ,真实辐射点落在以预定辐射点为中心 ,以 1 5和 1 2 5 μm为半径的圆内的概率分别为 99 1%和 97 9% ;如果样品架和图像处理系统共同作用 ,那么真实辐射点落在相应区域内的概率分别为 98 4 %和 96 4 %。在离子的分布上 ,大于 99 5 %的离子分布在以真实辐射点为中心、以 7 5 μm为直径的圆内 ,其中的 99 1%又集中在直径为 5

The localization irradiation accuracy of the microbeem generated in the Gay Laboratory cancer Research Trust in England was experimentally studied. The localization irradiation capability of the microbeam includes two aspects: the targeting location accuracy and the particle distribution size. The former depends on the micro-stage recalling capability and the cell finding accuracy of the micro-imaging system, whereas the latter on the collimator performance. The localized irradiation accuracy of the microbeam has been determined by analyzing the size and the position of the pit clusters on CR39 produced by 3.5 MeV helium ion 3He2+ irradiation. If the localization irradiation accuracy involves only the targeting location accuracy 99.1% and 97.9% of the realistic irradiation fall into a central area around the targeting location 1.50 μm and 1.25 μm in radial respectively. Once the micro-imaging system is included the percentages of the irradiation positions in the corresponding region changes to 98.4% and 96.4% respectively. When it comes to the particle distribution over 99.5% of the particle irradiation locate within a circle 7.5 μm in diameter around the targeting position and 99.1% of them concentrate in its center 5 μm in diameter.