重离子径迹影像探测器研制及初步实验测试

Development of a heavy ion track imaging detector and its preliminary experimental test

研制了一套基于气体雪崩电离室和CCD(charge-coupled device)影像获取系统的重离子径迹影像探测器。利用239Pu放出的α粒子,对所研制的重离子径迹影像探测器系统进行了初步的实验测试。测试结果显示,所研制的重离子径迹影像探测器系统能够成功地抓拍到α粒子的径迹,其径迹形貌与气体雪崩电离室中工作气体的气压、CCD相机的曝光时间等参数密切相关。对工作气体气压为15 hPa、曝光时间10 s的α粒子径迹影像数据分析表明,径迹分布呈轴对称,径迹宽度沿轴向逐渐减小,径迹影像的像点密度沿轴向逐渐增加。

Background： Heavy ion track is one kind of very important information for diotherapy study. Purpose： The aim is to study the spatial distribution of the heavy ions energy deposition when they pass through certain matter, especially the biological tissue. Methods： A heavy ion track imaging detector system which is based on gas avalanche chamber and charge-coupled device （CCD） optical readout system was developed. Preliminary experimental test was performed, in which a particle radiated from ^239Pu was used as the incident particle. Results： a particle track imaging was achieved successfully. It is found that a particle track is closely related to the gas pressure in the avalanche chamber and the exposure time of the CCD camera. According to analyzing the data of a particle track under the condition of gas pressure equivalent to 15 hPa and exposure time equivalent to 10 s, it is proved that the track structure is axisymmetric. With incident depth increasing, the track spread decreases gradually, and the image points density increases. Conclusion： We developed the heavy ion track imaging detector system which can achieve a particle track imaging successfully, and some preliminary law of charged particle track can be found.