Scattering of relativistic electrons by a thin bimetallic foil

Abstract

Angles of refraction θ _d of electron beams passing through thin planar bimetallic foils and the angles of reflection φ _r of the beams reflected by these foils have been measured. The experiments were performed with a microtron with a particle energy of 7.4 MeV as the source of electrons and aluminum-lead and aluminum-copper foils. The thicknesses of aluminum, lead, and copper layers were 54 mg/cm² (200 μm), 44 mg/cm² (50 μm), and 79 mg/cm² (70 μm), respectively. The particles were injected at the angles α = 5°−30° to the foil surface. The measurements were performed at various orientations of a bimetal with respect to the trajectory of the beam. In the first case, the particles moving through the foil first crossed the aluminum layer and then the layer of a higher density metal (copper or lead). In the opposite case, the particles were injected into the copper or lead layer and then crossed the aluminum layer. It has been found that changing the order of the metallic layers to the opposite one considerably affects the angles of reflection and refraction at some angles of incidence. Similar measurements have been carried out for electrons incident on scatterers made of homogeneous metals (aluminum, copper, and lead). Comparison with the experiments with bimetallic foils allows estimating the contribution of each layer to refraction and reflection of the injected beam.