Critical minima in elastic electron scattering by argon

Abstract

We determined experimentally two critical points in elastic electron scattering by argon where the differential cross section (DCS) attains its smallest values. The points were found to be at 68.5 • ± 0.3 • , 41.30 ± 0.02 eV and at 143.5 • ± 0.3 • , 37.30 ± 0.02 eV. Special attention was given to improve the angular resolution in order to determine the exact positions of the minima. These minima are important because they are a sensitive test of the validity of experimental procedures, and are used to verify theoretical predictions of DCS shapes and magnitudes, and of the polarization of scattered electrons. Normalized DCS were determined by measuring the angular distributions of elastically scattered electrons at incident energies of 10, 15, 20, 25, 30, 40, 50, 60, 75, 80, 90 and 100 eV in the angular range 20 • -150 • . Results are compared with the available experimental and theoretical data. In addition, integral, momentumtransfer, and viscosity cross sections were determined by numerical integration of the measured DCS extrapolated to 0 • and to 180 • .

Experimental and theoretical study of the triple-differential cross section for electron-impact ionization of thymine molecules

“…The two electron energy analyzers are mounted on independent turntables concentric with the interaction region. The detection energies of the hemispherical electron energy analyzers have been calibrated using the L 2,3 M 2,3 M 2,3 Auger spectrum of argon [22], while the angular calibration of the analyzers has been determined using the well-defined minimum in the differential cross section for elastic scattering of 60 eV electrons from argon [23].…”

Contribution of electron-atom collisions to the plasma conductivity of noble gases

“…(14), (15), (19) and (22) in comparison with the optical potential used in [25]. Also shown are experimental data [49][50][51][52][53][54][55][56][57][58][59][60][61][62][63].…”

Dynamical (e,2e) studies of tetrahydrofurfuryl alcohol

“…The detection energies of the hemispherical electron energy analyzers have been calibrated using the L 2,3 M 2,3 M 2,3 Auger spectrum of argon, 27 while the angular calibration of the analyzers has been determined using the well-defined minimum in the differential cross section for elastic scattering of 60 eV electrons from argon. 28 In dynamical TDCS measurements, the scattered electron is detected at a fixed forward scattering angle (θ a ) with respect to the incident electron beam direction, while ejected electron angular distributions are measured by scanning the ejected electron energy analyzer and detecting electrons at a number of different ejected electron angles (θ b ) within the scattering plane. The number of true coincidence events detected at each ejected electron angle is proportional to the TDCS.…”