Kinetic theory of positron-impact ionization in gases

G. J. Boyle; W. J. Tattersall; D. G. Cocks; S. Dujko; R. D. White

doi:10.1103/PhysRevA.91.052710

Kinetic theory of positron-impact ionization in gases

G. J. Boyle^*, W. J. Tattersall, D. G. Cocks, S. Dujko, R. D. White

^*Corresponding author for this work

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

27 Citations (Scopus)

Abstract

A kinetic theory model is developed for positron-impact ionization (PII) with neutral rarefied gases. Particular attention is given to the sharing of available energy between the postionization constituents. A simple model for the energy-partition function that qualitatively captures the physics of high-energy and near-threshold ionization is developed for PII, with free parameters that can be used to fit the model to experimental data. By applying the model to the measurements of Kover and Laricchia [Phys. Rev. Lett. 80, 5309 (1998)PRLTAO0031-900710.1103/PhysRevLett.80.5309] for positrons in H2, the role of energy partitioning in PII for positron thermalization is studied. Although the overall thermalization time is found to be relatively insensitive to the energy partitioning, the mean energy profiles at certain times can differ by more than an order of magnitude for the various treatments of energy partitioning. This can significantly impact the number and energy distribution of secondary electrons.

Original language	English
Article number	052710
Journal	Physical Review A - Atomic, Molecular, and Optical Physics
Volume	91
Issue number	5
DOIs	https://doi.org/10.1103/PhysRevA.91.052710
Publication status	Published - 27 May 2015

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title = "Kinetic theory of positron-impact ionization in gases",

abstract = "A kinetic theory model is developed for positron-impact ionization (PII) with neutral rarefied gases. Particular attention is given to the sharing of available energy between the postionization constituents. A simple model for the energy-partition function that qualitatively captures the physics of high-energy and near-threshold ionization is developed for PII, with free parameters that can be used to fit the model to experimental data. By applying the model to the measurements of Kover and Laricchia [Phys. Rev. Lett. 80, 5309 (1998)PRLTAO0031-900710.1103/PhysRevLett.80.5309] for positrons in H2, the role of energy partitioning in PII for positron thermalization is studied. Although the overall thermalization time is found to be relatively insensitive to the energy partitioning, the mean energy profiles at certain times can differ by more than an order of magnitude for the various treatments of energy partitioning. This can significantly impact the number and energy distribution of secondary electrons.",

author = "Boyle, \{G. J.\} and Tattersall, \{W. J.\} and Cocks, \{D. G.\} and S. Dujko and White, \{R. D.\}",

note = "Publisher Copyright: {\textcopyright} 2015 American Physical Society.",

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doi = "10.1103/PhysRevA.91.052710",

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T1 - Kinetic theory of positron-impact ionization in gases

AU - Boyle, G. J.

AU - Tattersall, W. J.

AU - Cocks, D. G.

AU - Dujko, S.

AU - White, R. D.

PY - 2015/5/27

Y1 - 2015/5/27

N2 - A kinetic theory model is developed for positron-impact ionization (PII) with neutral rarefied gases. Particular attention is given to the sharing of available energy between the postionization constituents. A simple model for the energy-partition function that qualitatively captures the physics of high-energy and near-threshold ionization is developed for PII, with free parameters that can be used to fit the model to experimental data. By applying the model to the measurements of Kover and Laricchia [Phys. Rev. Lett. 80, 5309 (1998)PRLTAO0031-900710.1103/PhysRevLett.80.5309] for positrons in H2, the role of energy partitioning in PII for positron thermalization is studied. Although the overall thermalization time is found to be relatively insensitive to the energy partitioning, the mean energy profiles at certain times can differ by more than an order of magnitude for the various treatments of energy partitioning. This can significantly impact the number and energy distribution of secondary electrons.

AB - A kinetic theory model is developed for positron-impact ionization (PII) with neutral rarefied gases. Particular attention is given to the sharing of available energy between the postionization constituents. A simple model for the energy-partition function that qualitatively captures the physics of high-energy and near-threshold ionization is developed for PII, with free parameters that can be used to fit the model to experimental data. By applying the model to the measurements of Kover and Laricchia [Phys. Rev. Lett. 80, 5309 (1998)PRLTAO0031-900710.1103/PhysRevLett.80.5309] for positrons in H2, the role of energy partitioning in PII for positron thermalization is studied. Although the overall thermalization time is found to be relatively insensitive to the energy partitioning, the mean energy profiles at certain times can differ by more than an order of magnitude for the various treatments of energy partitioning. This can significantly impact the number and energy distribution of secondary electrons.

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DO - 10.1103/PhysRevA.91.052710

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JO - Physical Review A - Atomic, Molecular, and Optical Physics

JF - Physical Review A - Atomic, Molecular, and Optical Physics

IS - 5

M1 - 052710

ER -

Kinetic theory of positron-impact ionization in gases

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