An electron-atom crossed beam apparatus and its first applications

Abstract

An electron-atom crossed beam apparatus has been designed and constructed. The set up uses an electron impact spectrometer in which electrons with a well defined energy are crossed with atomic target beams. The apparatus can be used for optical excitation measurements as well as for energy loss and elastic scattering experiments. Observations can be made at fixed or variable angles. Owing to the availability of independent detection channels for scattered electrons and photons it is possible to use the apparatus to make coincidence measurements. The instrument has so far been used to study elastic scattering of electrons from atomic hydrogen and helium and for energy loss observations with helium. Further investigations have been made of the resonance structure in the excitation of first excitation levels of Ne, Ar, Kr and Xe, as well as in the 2S excitation of atomic hydrogen.