测量离子束横向截面的闪烁体屏的热分析

针对基于闪烁屏-CCD(电荷耦合元件)相机的氘离子束横向强度分布测量系统，利用ANSYS软件模拟计算了在直流及脉冲模式下，能量100 keV、束斑直径3 mm氘离子轰击造成的Al₂O₃, SiO₂以及锗酸铋(BGO)三种候选闪烁体材料的表面温度变化。结果表明，在30 μA的直流氘离子束轰击下，闪烁体表面温度随辐照时间急剧地升高。持续时间10 min的氘离子束轰击将使三种材料前表面的温度分别升高131，234和649 ℃。对于峰值流强30 μA、重复频率1 Hz、脉宽5 μs的重复频率脉冲氘离子束，每个脉冲引起的三种闪烁屏表面的温度升高均小于0.05 ℃，且长时间的离子辐照基本不会造成闪烁屏的表面温度有明显的升高。对于脉宽5 μs的单脉冲氘离子束，三种材料的表面温度均随离子流强近似呈线性地增加。在单脉冲模式下，Al₂O₃，SiO₂以及BGO闪烁屏能允许的最高离子流强分别为2.32，1.08和0.72 A，超过此流强其表面温度将达到熔点。

Thermal effect of scintillation screens used for low energy deuterium ion beam profiling

The neutron generator is widely used in the fields of oil logging and element on-line analysis. The measurement of the transverse intensity distribution of the deuterium ion beam at the target position is of great significance to the improvement and optimization of the neutron generator. For Al₂O₃, SiO₂ and BGO scintillation screens used for transverse ion beam profile measurements, the temperature rises of the materials caused by 100 keV and 3 mm in diameter deuterium ion beam radiation was calculated with ANSYS software. The results show that, for 30 μA DC deuterium ion beam, the surface temperatures of the scintillation screens increased dramatically with the irradiation time. After a total irradiation time of 10 minutes, the surface temperatures of the Al₂O₃, SiO₂ and BGO screens had increased by 131, 234 and 649 ℃ respectively. For pulsed ion beam with beam current of 30 μA, 1 Hz repetition rate and 5 μs pulse width, the temperature rise caused by a single beam pulse of the three scintillation screens were all less than 0.05 ℃, and the average temperatures of the scintillation screens almost kept unchanged even for long time ion irradiation. For a single pulsed deuterium ion beam with a beam width of 5 μs, the temperature change of the scintillation screens as the beam intensity varied was calculated. The results show that, the temperature of scintillation screens almost increased linearly with the beam current, and the maximum ion current allowed for Al₂O₃, SiO₂ and BGO scintillation screens was 2.32 A, 1.08 A and 0.72 A, respectively. For ion beam with current larger than the maximum allowed ion current, the surface temperature would reach the melting point of the materials.