Time-of-flight velocity analysis of atomic and molecular beams
Time-of-flight velocity analysis of atomic and molecular beams
复制标题
原子束和分子束的飞行时间速度分析
DOI：
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发表时间：
1968
期刊：
影响因子：
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通讯作者：
A. Varma
中科院分区：
文献类型：
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作者：
O. Hagena;A. Varma
本文系统地分析了用于测量分子束速度分布的飞行时间（TOF）方法。通过计算对于有限的光束快门打开时间τ的TOF信号来评估解析给定的光束速度分布所需的条件。如果分辨率R=Δt/τ等于或大于5，则TOF信号的半宽度Δt超过理想半宽度Δt0（对于τ→0）不超过2.5%。峰值信号幅度Um不小于0.8 U 0/R，其中U 0是对应于未斩波光束（τ→∞）的信号。从分辨率、测量速度范围和最佳信噪比等方面讨论了光束斩波器和检测系统的设计准则。描述了一种用于探测大速比高强度分子束和低强度散射束的飞行时间系统，并给出了典型的实验结果。
A systematic analysis of the time‐of‐flight (TOF) method for measuring the distribution of speeds in molecular beams is presented. The conditions required for resolving a given beam speed distribution are evaluated by calculating the TOF signal for a finite open time τ of the beam shutter. The halfwidth of the TOF signal Δt exceeds the ideal half width Δt0(for τ→0) by not more than 2.5%, if the resolution R=Δt/τ is equal to or larger than 5. The peak signal amplitude Um is not less than 0.8 U0/R, where U0 is the signal corresponding to the unchopped beam (τ→∞). Design criteria for beam chopper and detection system are discussed in terms of the resolution, the range of speeds to be measured, and the optimum signal‐to‐noise ratio. A TOF system used for the detection of high‐intensity molecular beams with large speed ratio, as well as for low‐intensity scattered beams, is described and typical experimental results are presented.