Elastic scattering of low-energy positrons by bound silicon and germanium

Journal Article · Fri Mar 15 04:00:00 EST 1991 · Journal of Applied Physics; (USA)

DOI:https://doi.org/10.1063/1.348471· OSTI ID:5715690

Antolak, A J ^[1]; Williamson, W Jr ^[2]

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1. Sandia National Laboratories, Liverlmore, CA (USA). Theoretical Division
2. University of Toledo, OH (USA). Department of Physics and Astronomy

Elastic scattering differential and total cross sections for low-energy positron collisions with bound silicon and germanium atoms have been computed using partial wave analysis with static and polarization potentials. The calculations are performed at incident positron energies ranging from 0.2 to 500 eV. For each impact energy, an appropriate number of phase shifts are obtained by numerically integrating the radial wave equation to ensure convergence of the scattering amplitude. A simple parametrization of the total cross section in terms of the screened Rutherford cross section is also presented for use in Monte Carlo codes.Due, in part, to the lack of reliable experimental data, relatively little theoretical work has been done to calculate the inelastic and elastic differential cross sections (DCS) and total cross sections (TCS) for positron scattering. Most of the measurements were made on noble gases where it is observed that low-energy positrons exhibit a Ramsauer--Townsend (RT) minimum for helium, neon, and possibly argon (for electrons, the RT minimum occurs for heavier noble gases).{sup 1,2} Calculations of the positron TCS for these atoms agree with the observations. The RT effect has also been identified in a number of other free atoms and molecules for electrons.{sup 3,4} Recently, Meredith {ital et} {ital al}. computed the electron elastic scattering cross sections in solid silicon and germanium.{sup 5} In this work we calculate the DCS and TCS for positrons elastically scattered by silicon and germanium atoms which are bound in an amorphous solid using partial waves and the optical model. The results are presented for incident positron energies ranging from 0.2 to 500 eV. Simple fits to each TCS are given for use in Monte Carlo scattering simulations.

• DOE Contract Number: AC04-76DP00789
• OSTI ID: 5715690
• Journal Information: Journal of Applied Physics; (USA), Journal Name: Journal of Applied Physics; (USA) Vol. 69:6; ISSN 0021-8979; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

640304* -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
AMPLITUDES
ANTILEPTONS
ANTIMATTER
ANTIPARTICLES
ATOM COLLISIONS
COLLISIONS
CROSS SECTIONS
DIFFERENTIAL CROSS SECTIONS
ELASTIC SCATTERING
ELEMENTARY PARTICLES
ELEMENTS
ENERGY RANGE
EV RANGE
EV RANGE 100-1000
FERMIONS
GERMANIUM
LEPTONS
METALS
MILLI EV RANGE
MONTE CARLO METHOD
NATIONAL ORGANIZATIONS
OPTICAL MODELS
PARTIAL WAVES
POSITRON COLLISIONS
POSITRON-ATOM COLLISIONS
POSITRONS
SANDIA LABORATORIES
SCATTERING
SCATTERING AMPLITUDES
SEMIMETALS
SILICON
TOTAL CROSS SECTIONS
US AEC
US DOE
US ERDA
US ORGANIZATIONS