Positron transport in CF4 and N-2/CF4 mixtures

Banković, Ana, Dujko, Saša, Marjanović, Srdjan, White, Ronald D., and Petrović, Zoran Lj. (2014) Positron transport in CF4 and N-2/CF4 mixtures. The European Physical Journal D, 68 (127). pp. 1-10.

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Abstract

In this paper we present our recently compiled set of cross sections for positron scattering in CF4. Using this set of cross sections as an input in our multi term Boltzmann equation analysis of positron transport in CF4 and N-2/CF4 mixtures, we calculate various transport properties as a function of the reduced electric field E/n (0). Values and general trends of the mean energy, drift velocity and diffusion coefficients as a function of E/n (0) are reported here. Emphasis is placed on the explicit and implicit effects of positronium (Ps) formation on the drift velocity and diffusion coefficients. Two important phenomena arise. Firstly, for certain regions of E/n (0) the bulk and the flux components of the drift velocity and longitudinal diffusion coefficient are markedly different, both qualitatively and quantitatively. Secondly, and contrary to previous studies in positron swarm studies, there is negative differential conductivity (NDC) in both the bulk and flux drift velocity. The variation of the drift velocity with E/n (0) and origin of the NDC are addressed using physical arguments. Cross sections and transport data for positrons in CF4 and N-2/CF4 mixtures presented in this work are compiled and evaluated with an aim of improving the efficiency of positron traps.

Item ID: 33873
Item Type: Article (Research - C1)
ISSN: 1434-6079
Funders: MPNTRS, Australian Research Council (ARC)
Projects and Grants: MPNTRS Project ON171037, MPNTRS Project III41011
Date Deposited: 25 Jun 2014 09:01
FoR Codes: 02 PHYSICAL SCIENCES > 0202 Atomic, Molecular, Nuclear, Particle and Plasma Physics > 020201 Atomic and Molecular Physics @ 80%
02 PHYSICAL SCIENCES > 0204 Condensed Matter Physics > 020404 Electronic and Magnetic Properties of Condensed Matter; Superconductivity @ 20%
SEO Codes: 97 EXPANDING KNOWLEDGE > 970102 Expanding Knowledge in the Physical Sciences @ 100%
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