【摘要】 介绍一种用于中国科学院近代物理研究所(IMP)重离子肿瘤治疗线上、于纵向场常压下工作的气体电离室,其灵敏面积为250mm×250mm,极间距离为10mm,电离室工作气体为P10,在85kPa下流气式工作。用75MeV/u12C离子入射,测量了电离室的坪曲线。发现电离室工作坪区900—3000V,12C的Bragg峰位于13.73mm,峰的极大值半高宽(FWHM)为0.19mm。更多还原

【Abstract】 An ionization chamber (IC) with a sensitive area of 250mm×250 mm was developed for the Institute of Modern Physics (IMP) heavy ion therapy facility. The gap was 10 mm between the anode and the cathode. A good plateau was seen in a large voltage range from 900V to 3000V when the IC was operated at (85.0±0.2) kPa with P10 (10% CH4+90% Ar) as flowing gas. By putting the different thicknesses of polymethyl methacrylate (PMMA) in front of the IC, the Bragg curve for the beam in PMMA was measured by the IC. During the test, the voltage of 2300 V was applied to the anode of the IC. The measured Bragg peak for 75 MeV/u 12C6+ ions in the PMMA was located at 13.73 mm and the FWHM was 0.19mm.更多还原