论文标题
GEANT4对HADRONTHERAPY横截面测量的FRACAS设备的系统研究
Geant4 Systematic Study of the FRACAS Apparatus for Hadrontherapy Cross Section Measurements
论文作者
论文摘要
在这项工作中，我们报告了FRACAS设备的系统蒙特卡洛（MC）研究，这是一种较大的接受质谱仪，将用于测量$^{12} $ c离子的碎片横截面以用于放体疗法。放置在100 MBAR反应室中的设备将由梁显示器，磁铁周围的跟踪器和飞行时间（TOF）壁制成。为了确定跟踪器的所需性能，使用了整个系统和内部开发算法的GEANT4模拟。在保持光束监视器和TOF壁位置固定的同时，已经提取了跟踪器位置和空间分辨率对轨迹重建和质量识别效率的影响。发现了最佳配置，其中上游跟踪器应位于距离目标6厘米的地方，间隔4厘米，而其空间分辨率应接近100 $μ$ m。必须根据光束能量来更改下游跟踪器的位置，以保持高识别效率。他们的空间分辨率，即使与上游跟踪器相比的重要性较小，也应大约1毫米或更高。在这种最佳构型中，对于范围为100至400 meV/核的束能量，已经获得了超过90％的整体片段识别效率。
In this work, we report on systematic Monte Carlo (MC) studies for the FRACAS apparatus, a large acceptance mass spectrometer that will be used to measure the fragmentation cross sections of $^{12}$C ions for hadrontherapy. The apparatus placed, in a 100 mbar reaction chamber, will be made of a beam monitor, trackers surrounding a magnet and a Time-Of-Flight (TOF) wall. In order to determine the required performances of the trackers, Geant4 simulations of the whole system and in-house developed algorithms were used. While keeping the beam monitor and TOF-wall positions fixed, the effects of the tracker positions and spatial resolutions on the trajectory reconstruction and mass identification efficiencies have been extracted. An optimal configuration was found where the upstream trackers should be located 6 cm away from the target and spaced 4 cm apart whereas their spatial resolutions should be close to 100 $μ$m. The positions of the downstream trackers will have to be changed according to the beam energy to preserve high identification efficiencies. Their spatial resolutions, even though of a lesser importance compared to the upstream trackers, should be around 1 mm or better. In this optimal configuration, an overall fragment identification efficiency above 90% has been obtained for beam energies ranging from 100 to 400 MeV/nucleon.
