Integral measurements of plural and multiple scattering of electrons with energies between 10 and 100 keV for

Suelen F. Barros, Alice Dias Petri, A.A. Malafronte,José M. Fernández-Varea,Nora L. Maidana, M. C. Martins, V. R. Vanin, A. Mangiarotti

Angle-integrated multiple-scattering distributions are presented for electrons with energies between 10 and 100 keV hitting Al, Cu, Sn, and Au foils. The present results differ from those published in part I (Barros et al., 2023) because the targets have ≈10 times larger mass thicknesses of the order of ≈1.5 to 5 mg/cm2. It is then possible to follow, by increasing the beam energy, the behaviour around the point of punch-through of the electrons (when a small fraction begins to cross the target, between ≈30 to 60 keV depending on the material and thickness) up to 100 keV, where absorption in the target itself is small. The measurements were performed together with those of part I employing the same setup. The electrons have been collected with a Faraday cup, accepting the most frontal scattering angles, and a ring, that surrounds the entrance of the cup, still covering rather forward deflections. The normalisation is provided by measuring the current in the chamber, which close-up completely the remaining solid angle, and the electrons stopped within the target, which is also electrically connected to the chamber. The same corrections for the electrons backscattered by the Faraday cup and the ring found in part I are applied. The measurements, all referring to homogeneous targets, are compared with the predictions of the Goudsmit–Saunderson and Lewis analytical approaches and to the PENELOPE-2018 Monte Carlo code to take into account, as far as possible, the effect of the energy loss. In all cases, the elastic differential cross sections are those of the ICRU Report 77, ensuing from a partial-wave solution of the Dirac equation in a self-consistent isolated-atom central potential. While the analytical calculations do not work, in general, for the thick targets, good agreement is found between simulations and measurements.