Transport theory for low-energy positron thermalization and annihilation in helium

G.J Boyle; MJE Casey; RD White; James Mitroy

doi:10.1103/PhysRevA.89.022712

Transport theory for low-energy positron thermalization and annihilation in helium

G.J Boyle, MJE Casey, RD White, James Mitroy

Research output: Contribution to journal › Article › peer-review

Abstract

A transport theory that explicitly incorporates loss of flux due to annihilating collisions is developed and applied to low-energy positron diffusion and annihilation. The use of more complete momentum transfer and annihilation cross sections for helium has resulted in improved descriptions of the time dependence of ?Zeff? for positrons injected into gaseous helium. Similarly, the variation of ?Zeff? versus E/n0 for experiments where the annihilation region is immersed in an electric field is in closer agreement with experimental data. Inclusion of loss of flux due to annihilation was found to have a very small effect on the derived ?Zeff(t)? for helium. � 2014 American Physical Society.

Original language	English
Pages (from-to)	1-9
Number of pages	9
Journal	Physical Review A - Atomic, Molecular, and Optical Physics
Volume	89
Issue number	2
DOIs	https://doi.org/10.1103/PhysRevA.89.022712
Publication status	Published - 28 Feb 2014

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10.1103/PhysRevA.89.022712

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title = "Transport theory for low-energy positron thermalization and annihilation in helium",

abstract = "A transport theory that explicitly incorporates loss of flux due to annihilating collisions is developed and applied to low-energy positron diffusion and annihilation. The use of more complete momentum transfer and annihilation cross sections for helium has resulted in improved descriptions of the time dependence of ?Zeff? for positrons injected into gaseous helium. Similarly, the variation of ?Zeff? versus E/n0 for experiments where the annihilation region is immersed in an electric field is in closer agreement with experimental data. Inclusion of loss of flux due to annihilation was found to have a very small effect on the derived ?Zeff(t)? for helium. � 2014 American Physical Society.",

keywords = "Annihilation cross sections, Gaseous helium, Positron diffusion, Thermalization, Time dependence, Transport theory, Electric fields, Electrons, Positrons, Statistical mechanics, Helium",

author = "G.J Boyle and MJE Casey and RD White and James Mitroy",

year = "2014",

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day = "28",

doi = "10.1103/PhysRevA.89.022712",

language = "English",

volume = "89",

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T1 - Transport theory for low-energy positron thermalization and annihilation in helium

AU - Boyle, G.J

AU - Casey, MJE

AU - White, RD

AU - Mitroy, James

PY - 2014/2/28

Y1 - 2014/2/28

N2 - A transport theory that explicitly incorporates loss of flux due to annihilating collisions is developed and applied to low-energy positron diffusion and annihilation. The use of more complete momentum transfer and annihilation cross sections for helium has resulted in improved descriptions of the time dependence of ?Zeff? for positrons injected into gaseous helium. Similarly, the variation of ?Zeff? versus E/n0 for experiments where the annihilation region is immersed in an electric field is in closer agreement with experimental data. Inclusion of loss of flux due to annihilation was found to have a very small effect on the derived ?Zeff(t)? for helium. � 2014 American Physical Society.

AB - A transport theory that explicitly incorporates loss of flux due to annihilating collisions is developed and applied to low-energy positron diffusion and annihilation. The use of more complete momentum transfer and annihilation cross sections for helium has resulted in improved descriptions of the time dependence of ?Zeff? for positrons injected into gaseous helium. Similarly, the variation of ?Zeff? versus E/n0 for experiments where the annihilation region is immersed in an electric field is in closer agreement with experimental data. Inclusion of loss of flux due to annihilation was found to have a very small effect on the derived ?Zeff(t)? for helium. � 2014 American Physical Society.

KW - Annihilation cross sections

KW - Gaseous helium

KW - Positron diffusion

KW - Thermalization

KW - Time dependence

KW - Transport theory

KW - Electric fields

KW - Electrons

KW - Positrons

KW - Statistical mechanics

KW - Helium

U2 - 10.1103/PhysRevA.89.022712

DO - 10.1103/PhysRevA.89.022712

M3 - Article

VL - 89

SP - 1

EP - 9

JO - Physical Review A

JF - Physical Review A

SN - 1050-2947

IS - 2

ER -

Transport theory for low-energy positron thermalization and annihilation in helium

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