Schofield N E, Paganin D M, Bishop A I
School of Physics, Monash University, Victoria 3800, Australia.
Rev Sci Instrum. 2009 Dec;80(12):123105. doi: 10.1063/1.3264079.
We describe an approach for the absolute density measurement of rotationally symmetric molecular beams via multiphoton ionization. This simple single-projection tomographic technique requires only knowledge of the spatial intensity profile and ionization characteristics of the focused laser beam that probes the pulsed molecular jet. Multiphoton ionization (MPI) of a xenon beam allowed tomographic reconstruction of a two-dimensional density profile with a peak density of (4.2+/-0.4)x10(18) m(-3), which was compared with the theoretical predictions of the sudden freeze model. An analytic solution to the Abel transform is derived for Gaussian projected density profiles which greatly simplifies the reconstruction of the absolute radial density. MPI is sufficiently general that this technique can be readily applied to atomic beams with a broad range of chemistries.
我们描述了一种通过多光子电离对旋转对称分子束进行绝对密度测量的方法。这种简单的单投影层析成像技术仅需要了解探测脉冲分子射流的聚焦激光束的空间强度分布和电离特性。氙束的多光子电离使得能够对二维密度分布进行层析重建，其峰值密度为(4.2±0.4)×10¹⁸ m⁻³，并将其与突然冻结模型的理论预测进行了比较。针对高斯投影密度分布推导了阿贝尔变换的解析解，这极大地简化了绝对径向密度的重建。多光子电离具有足够的通用性，以至于该技术可以很容易地应用于具有广泛化学性质的原子束。
