TY - JOUR

T1 - Energy loss by non-relativistic electrons and positrons in liquid water

AU - Pimblott, Simon M.

AU - Siebbeles, Laurens D.A.

N1 - Funding Information:
The research described was supported in part by the Office of Basic Energy Science of the US Department of Energy. This is contribution NDRL-4333 of the Notre Dame Radiation Laboratory.

PY - 2002/9

Y1 - 2002/9

N2 - Inelastic collision cross-sections, mean free paths, stopping powers, energy loss distributions, mean energy losses and csda ranges are evaluated for non-relativistic electrons and positrons in liquid water using a formalism in which the response of the medium is expressed employing the experimental dipole oscillator strength distribution. Monte Carlo track structure simulations employing the calculated inelastic collision cross-sections, and elastic cross-sections evaluated using partial wave methods, are used to determine the energy dependence of positron and electron path-lengths, penetrations, and non-homogeneous energy deposition distributions. The calculated data are discussed, and compared and contrasted. The energy loss properties of electrons and positrons that depend only on the differential inelastic collision cross-section are similar for particle energies ≳ 1 keV, but there are apparent differences for lower energies. The energy loss properties depending on the size of the energy transfer events and on the differential inelastic collision cross-section differ for all particle energies. The differences found are the consequence of electron indistinguishability on the inelastic cross-section for the electron. Non-homogeneous energy deposition distributions of positrons with energy less than 1 keV are significantly more forward directed than those of electrons with the same initial energy. The differences are due to the larger inelastic collision cross-section of a positron compared to an electron, and its effect on the relative numbers of inelastic and elastic collisions.

AB - Inelastic collision cross-sections, mean free paths, stopping powers, energy loss distributions, mean energy losses and csda ranges are evaluated for non-relativistic electrons and positrons in liquid water using a formalism in which the response of the medium is expressed employing the experimental dipole oscillator strength distribution. Monte Carlo track structure simulations employing the calculated inelastic collision cross-sections, and elastic cross-sections evaluated using partial wave methods, are used to determine the energy dependence of positron and electron path-lengths, penetrations, and non-homogeneous energy deposition distributions. The calculated data are discussed, and compared and contrasted. The energy loss properties of electrons and positrons that depend only on the differential inelastic collision cross-section are similar for particle energies ≳ 1 keV, but there are apparent differences for lower energies. The energy loss properties depending on the size of the energy transfer events and on the differential inelastic collision cross-section differ for all particle energies. The differences found are the consequence of electron indistinguishability on the inelastic cross-section for the electron. Non-homogeneous energy deposition distributions of positrons with energy less than 1 keV are significantly more forward directed than those of electrons with the same initial energy. The differences are due to the larger inelastic collision cross-section of a positron compared to an electron, and its effect on the relative numbers of inelastic and elastic collisions.

KW - Attenuation

KW - Implantation

KW - Liquid water

KW - Positron

KW - Range

UR - http://www.scopus.com/inward/record.url?scp=0036723292&partnerID=8YFLogxK

U2 - 10.1016/S0168-583X(02)00693-6

DO - 10.1016/S0168-583X(02)00693-6

M3 - Article

AN - SCOPUS:0036723292

SN - 0168-583X

VL - 194

SP - 237

EP - 250

JO - Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms

JF - Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms

IS - 3

ER -