Title of Oral/Poster Presentation

Electron Penetration Range for Diverse Materials

Class

Article

Department

Physics

Faculty Mentor

John Dennison

Presentation Type

Poster Presentation

Abstract

The penetration range of energetic electrons into diverse materials can be modeled approximately with a simple fit. This fit is a function of a single parameter, Nv, which describes the effective number of valence electrons. Using the Continuous-Slow-Down-Approximation (CSDA) for energy deposition in a material, a composite analytic formula has been developed which estimates the range or maximum penetration depth of incident electrons for energies from <10 eV to >10 MeV with an uncertainty of <20%. The fit also incorporates several common properties compiled for each material, including the mean atomic number, mean atomic weight, density, and band gap or Plasmon energy. The model has been fit to existing data for 247 materials collected from the ESTAR and IMFP databases compiled by NIST to determine Nv values. Comparison of Nv with the material's properties from this large material database may lead to the prediction of Nv for materials which have no supporting data. These calculations are of great value for studies of high energy electron bombardment, such as electron spectroscopy, radiation damage or spacecraft charging. This research may also be applied in the medical field to uncharacterized complex biological materials, thereby improving physical selectivity in radiation therapy.

Start Date

4-9-2015 3:00 PM

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Apr 9th, 3:00 PM

Electron Penetration Range for Diverse Materials

The penetration range of energetic electrons into diverse materials can be modeled approximately with a simple fit. This fit is a function of a single parameter, Nv, which describes the effective number of valence electrons. Using the Continuous-Slow-Down-Approximation (CSDA) for energy deposition in a material, a composite analytic formula has been developed which estimates the range or maximum penetration depth of incident electrons for energies from <10 eV to>10 MeV with an uncertainty of <20%. The fit also incorporates several common properties compiled for each material, including the mean atomic number, mean atomic weight, density, and band gap or Plasmon energy. The model has been fit to existing data for 247 materials collected from the ESTAR and IMFP databases compiled by NIST to determine Nv values. Comparison of Nv with the material's properties from this large material database may lead to the prediction of Nv for materials which have no supporting data. These calculations are of great value for studies of high energy electron bombardment, such as electron spectroscopy, radiation damage or spacecraft charging. This research may also be applied in the medical field to uncharacterized complex biological materials, thereby improving physical selectivity in radiation therapy.