Formulas, Facts and Constants for Students and Professionals in Engineering, Chemistry, and Physics

Inelastic differential electron scattering cross sections of molecular oxygen (O2) in the 20-100 eV impact energy range

“…It was found that the centre of the He molecular flow regime corresponded to a backing pressure of approximately 0.9 Torr. Based on the work of Kanik (1988), along with the effective diameters of He, Ne and O 2 given by Fischbeck and Fischbeck (1987), Ne and O 2 backing pressures of approximately 0.64 and 0.34 Torr, respectively, were determined to be appropriate in the present relative flow measurements.…”

The geometric response function for convergent slit-slat collimators

“…We refer to this as the principal line , which in our geometry is the z axis. Thus, $$g_{\text{pri}}=\frac{d}{\pi (d+t)}true[{\tan }^{-1}\frac{\eta \lambda }{\sqrt{1+{\eta }^2+{\lambda }^2}}+\frac{1}{2\lambda }\log \frac{\sqrt{1+{\eta }^2+{\lambda }^2}+\eta }{\sqrt{1+{\eta }^2+{\lambda }^2}-\eta }-\frac{1}{2\lambda }\log \frac{\sqrt{1+{\eta }^2}+\eta }{\sqrt{1+{\eta }^2}-\eta }true]$$ The first term in (36) is the exact formula for the solid angle subtended by the normalized rectangular support of the point spread function [−ν, ν]×[−λ, λ] (Fischbeck and Fischbeck 1987). The second and third terms are caused by the triangular shape of the point spread function in the y direction.…”