Effect of finite scattering volume and detector geometry on measured electron-impact spectra in crossed-beam experiments

Abstract

Calculations are reported for the effects of finite scattering volume and detector geometry on electron‐impact intensity measurements in crossed‐beam experiments. The target and projectile beams are assumed to be Gaussian in cross‐section shape. Three cases for detector geometry are considered using rectangular apertures. The first case consists of a single rectangular aperture. The second case consists of an additional single slit with slit width perpendicular to the direction of target beam flow located between the scattering volume and the rectangular aperture. The third case consists of two apertures. Correction values for various experimental situations are given and theoretical results for the important case of zero scattering angle are compared with experiment.