Investigation for angular distribution of atomic helium double excitation-ionization resonance profiles

In this study, the angular spectrum of autoionization energy levels of helium atom was experimentally investigated using the electron spectrometry in Electron Collision Laboratory (e-COL) at Afyon Kocatepe University. The experimental setup in the electron collision laboratory (e-COL) consists of an electron gun, target gas atom (He), the analyzer that is designed to measure scattered and ejected electrons, and the Faraday Electron Collector (FET) that is used to measure the electron beam current. The angular distributions of the autoionization energy levels of the helium atom were determined by detecting the outgoing electrons after the excitation of it by 200 eV energetic electrons. Differential force cross section measurements (DCS) were made for 10o-130o angular range and for 32,5-35 eV resonance energy levels. Ionization from resonance energy levels and the direct ionization could not be separately observed due to overlapping in the spectra. While the symmetrical shapes of resonance profiles are variable for small angles, they become perfectly symmetrical for large angles.