Low energy elastic scattering of electrons from H2 and N2

Accurate normalized differential cross-sections for elastic electron scattering from H2 and N2 are reported. These measurements are obtained using the relative flow method with helium as the standard (calibrating) gas, except that a thin aperture source of gas is used, which obviates the need to know the gas kinetic molecular diameters of either the calibration gas (He) or the unknown gas (H2 or N2) whose differential cross-sections need to be determined. Our present measurements are found to be in very good agreement with past differential elastic electron scattering measurements using the relative flow with tube collimating sources and independently vindicate the application of the conventional relative flow method for 'hard-sphere' gases. They also resolve some observed differences between the differential cross-sections in the low incident energy region. They also provide a good test of our relative flow method for two well-known targets