超音速冷靶的性质与应用

对超音速冷靶的形成机理进行了系统介绍,并利用热力学、流体力学、Newton力学对超音速靶的形成过程和性质参数进行简要推导,并根据推导结果编写程序计算了气体靶的各种参数及其与冷靶喷嘴各种参数的关系,得到了不同实验条件下超音速靶的性质参数,与实验测得的数据吻合很好.最后,依据理论计算和实验结果的验证发现:降低靶气体的初始温度、初始气压及提高抽速,可以有效地减小气体靶的横向动量分散,有利于提高粒子与原子分子碰撞实验中反冲离子动量测量精度.实际中,在综合考虑实验中气体的初始气压的同时,还需要降低靶气体的初始温度,提高气体的抽速.

Properties and applications of cold supersonic gas jet

By analyzing the formation mechanism of a supersonic gas jet, a set of equations which describe the atomic beam properties were established. The influence of initial temperature, initial pressure, background gas pressure and pumping speed was discussed in detail. A simulation program was developed based on the equations, and the results under different initial conditions were obtained. The results are in good agreement with the experimental data, and suggest that, in order to get much smaller transverse momentum in collision experiments, it is necessary to lower the initial temperature and the initial pressure of the supersonic gas jet, together with increasing the pumping speed. These results are very instructive for construction of a new generation of cold supersonic gas jets.