Measurement of Double Differential Cross-Section for Electron Impact Ionization of Argon at 348 eV

Abstract

Renewed interest in measuring cross-sections for scattering electrons or positrons by noble gas atoms at intermediate energies has recently led to test various theoretical approximations. Ionization of the noble gases such as He, Ne, Ar, Kr, and Xe by electron impact is an important process in collision physics. Argon has been studied from the discharge point of view for more than 100 years and interest in this gas is due to several important fundamental and technical considerations. Cross-sections for electron-impact ionization have been measured and calculated since the early days of collision physics because of their importance to the kinetics and dynamics of collisions in relevance to many practical applications. Previous experimental measurements of double di erential cross-sections (DDCS) by electron impact for targets rather than helium are very few. The most itemized study is that of Opal et al. [1]. They presented DDCS data for several gases at di erent incident energies of a wide angular range. The literature contains the results from several experimental measurements on the double di erential cross-section studies of Ar. The elastic scattering of electrons by noble gases has been extensively studied and a large number of either theoretically or experimentally obtained relative and absolute di erential cross-sections are available at various incident electron energies and scattering angles. The critical minima appearing in Ar DCS spectra are the most sensitive test for comparison of experimental and theoretical results and, hence, give good possibilities for testing di erent theoretical models. DuBois and Rudd [2] measured DDCS for 100 500 eV electron impact of Ar including Ne, N2, and H2 data. Hippler et al. [3] and Chaudhry et al. [4] reported energy distributions of ejected electrons in double or (multiple) ionization of rare gases 300 eV to 10 keV electron impact. Another work is done by Santos et al. [5] at 500 750 and 1000 eV electron impact single or multiple ionization DDCSs of Ar. Yates and Khakoo [6] have presented DDCSs of Ar for near threshold electron impact single ionization of Ar at 17, 18, 20, and 30 eV. In this work, we used Ar target as a typical that is reasonable to expect to understand ionization mechanism of atomic systems. We have measured DDCS for asymmetric geometry for di erent kinematical conditions.