We describe the characterization of a pulsed supersonic rare gas beam which is intended to serve as an ultracold neutral atom target for the production of an ultrashort ion pulse via femtosecond photoionization. The velocity distribution of atoms entrained in the beam is measured and characterized by temperatures T_II and T_⊥ in directions along and perpendicular to the beam propagation, respectively. It is shown that T_⊥ values in the mK regime are achieved at distances of the order of 1000 mm from the nozzle. Moreover, the center beam density at this position is measured to be of the order of 10¹¹ atoms/cm³. Both findings are essential for the intended application and confirm the targeted beam specifications. Comparison with theoretical estimates reveals the well-known skimmer interference effect, which is found to reduce the beam density by more than one order of magnitude.

我们描述脉冲超音速稀有气体束的表征，该束旨在用作通过飞秒光电离产生超短离子脉冲的超冷中性原子靶。在光束夹带原子的速度分布被测量并且其特征在于内的温度T _II和T _⊥分别在方向沿着并垂直于该光束传播。它被示出是t _⊥在mK的制度值在从喷嘴千毫米量级的距离来实现的。此外，在该位置处的中心束密度经测量为约10 ¹¹原子/ cm ^3。。这两个发现对于预期的应用是必不可少的，并确定了目标光束的规格。与理论估计值的比较揭示了众所周知的撇渣器干扰效应，发现该效应使光束密度降低了一个数量级以上。