The detailed evolution process of deuterium and hydrogen supersonic molecular beam (SMB) was probed by one simple method based on the microphone. The velocity of the beam was measured by time-of-flight method, and the density was investigated by comparing the radial profiles of the SMB with the total amounts of molecules in the gas jet. The velocity and number density of deuterium SMB generated from a cylindrical nozzle were tested to be 1100 m/s and 3.6E15 cm−3 at axial distance of 1700 mm and stagnation pressure of 50 bar, which was about 30% lower than that of hydrogen SMB generated from the same nozzle, and was in consistent with the total number of molecules in deuterium gas jet that was 30% smaller than hydrogen. It is found that the use of a cylindrical nozzle and arrangement of a special skimmer can increase the central density of SMB by about 150% and 45%, while the utilization of one conical nozzle would increase the velocity of the SMB by 13%, these results could give great help in the SMB diagnostics and fueling of the nuclear fusion experiments.

中文翻译：

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氘/氢超音速分子气体射流速度和密度特性的诊断和改进

通过一种基于麦克风的简单方法探测了氘和氢超音速分子束 (SMB) 的详细演化过程。通过飞行时间法测量光束的速度，并通过比较 SMB 的径向轮廓与气体射流中的分子总量来研究密度。圆柱形喷嘴产生的氘 SMB 的速度和数密度在 1700 mm 的轴向距离和 50 bar 的停滞压力下测试为 1100 m/s 和 3.6E15 cm-3，比氢气低约 30% SMB 由同一喷嘴产生，与比氢小 30% 的氘气射流中的分子总数一致。