Measurement of Total Cross Sections for the Scattering of Low-Energy Electrons by Lithium, Sodium, and Potassium

Abstract

The atomic beam recoil technique has been used to measure the total cross sections for the scattering of electrons by lithium in the energy range of about 1 to 10 eV. In this method, the atom beam is crossfired by a modulated electron beam. Recoil results in a scattering out of the atom beam at the modulation frequency. A phase-sensitive lock-in amplifier is used to detect the atom-scattering signal, which is obtained here from a continuously oxygenated surface ionization detector. The angular resolution of the apparatus at 1 eV for lithium and potassium is approximately 9° and 14°, respectively, in the electron polar scattering angle.