Treating electron transport in MCNP{sup trademark}

Hughes, H G

Title: Treating electron transport in MCNP{sup trademark}

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Abstract

The transport of electrons and other charged particles is fundamentally different from that of neutrons and photons. A neutron, in aluminum slowing down from 0.5 MeV to 0.0625 MeV will have about 30 collisions; a photon will have fewer than ten. An electron with the same energy loss will undergo 10{sup 5} individual interactions. This great increase in computational complexity makes a single- collision Monte Carlo approach to electron transport unfeasible for many situations of practical interest. Considerable theoretical work has been done to develop a variety of analytic and semi-analytic multiple-scattering theories for the transport of charged particles. The theories used in the algorithms in MCNP are the Goudsmit-Saunderson theory for angular deflections, the Landau an theory of energy-loss fluctuations, and the Blunck-Leisegang enhancements of the Landau theory. In order to follow an electron through a significant energy loss, it is necessary to break the electron`s path into many steps. These steps are chosen to be long enough to encompass many collisions (so that multiple-scattering theories are valid) but short enough that the mean energy loss in any one step is small (for the approximations in the multiple-scattering theories). The energy loss and angular deflection of the electron duringmore »« less

Authors:: Hughes, H G

Publication Date:: Tue Dec 31 00:00:00 EST 1996

Research Org.:: Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

Sponsoring Org.:: USDOE, Washington, DC (United States)

OSTI Identifier:: 460773

Report Number(s):: LA-UR-96-4583; CONF-9605255-1
ON: DE97003094; TRN: 97:007238

DOE Contract Number:: W-7405-ENG-36

Resource Type:: Conference

Resource Relation:: Conference: Training course on use of MCNP in radiation protection dosimetry, Bologna (Italy), May 1996; Other Information: PBD: [1996]

Country of Publication:: United States

Language:: English

Subject:: 66 PHYSICS; 99 MATHEMATICS, COMPUTERS, INFORMATION SCIENCE, MANAGEMENT, LAW, MISCELLANEOUS; MONTE CARLO METHOD; CHARGED-PARTICLE TRANSPORT; M CODES; ELECTRONS; PROBABILITY; CHARGED-PARTICLE TRANSPORT THEORY; ENERGY LOSSES; STOPPING POWER; TAIL ELECTRONS; LANDAU FLUCTUATIONS; MULTIPLE SCATTERING; MULTIPLE COLLISION METHOD

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                    Hughes, H G. Treating electron transport in MCNP{sup trademark}.  United States: N. p., 1996. 
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                    Hughes, H G. Treating electron transport in MCNP{sup trademark}.  United States.

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                    Hughes, H G. 1996.  
        "Treating electron transport in MCNP{sup trademark}".  United States.  https://www.osti.gov/servlets/purl/460773.

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@article{osti_460773,

  title        = {Treating electron transport in MCNP{sup trademark}},

  author       = {Hughes, H G},

  abstractNote = {The transport of electrons and other charged particles is fundamentally different from that of neutrons and photons. A neutron, in aluminum slowing down from 0.5 MeV to 0.0625 MeV will have about 30 collisions; a photon will have fewer than ten. An electron with the same energy loss will undergo 10{sup 5} individual interactions. This great increase in computational complexity makes a single- collision Monte Carlo approach to electron transport unfeasible for many situations of practical interest. Considerable theoretical work has been done to develop a variety of analytic and semi-analytic multiple-scattering theories for the transport of charged particles. The theories used in the algorithms in MCNP are the Goudsmit-Saunderson theory for angular deflections, the Landau an theory of energy-loss fluctuations, and the Blunck-Leisegang enhancements of the Landau theory. In order to follow an electron through a significant energy loss, it is necessary to break the electron`s path into many steps. These steps are chosen to be long enough to encompass many collisions (so that multiple-scattering theories are valid) but short enough that the mean energy loss in any one step is small (for the approximations in the multiple-scattering theories). The energy loss and angular deflection of the electron during each step can then be sampled from probability distributions based on the appropriate multiple- scattering theories. This subsumption of the effects of many individual collisions into single steps that are sampled probabilistically constitutes the ``condensed history`` Monte Carlo method. This method is exemplified in the ETRAN series of electron/photon transport codes. The ETRAN codes are also the basis for the Integrated TIGER Series, a system of general-purpose, application-oriented electron/photon transport codes. The electron physics in MCNP is similar to that of the Integrated TIGER Series.},

  doi          = {},

  url          = {https://www.osti.gov/biblio/460773},
  journal      = {},
number       = ,

  volume       = ,

  place        = {United States},

  year         = {Tue Dec 31 00:00:00 EST 1996},

  month        = {Tue Dec 31 00:00:00 EST 1996}

}

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