\begin{center} Predictive Formula for Electron Range over a Large Span of Energies \end{center}

POSTER

Abstract

A model has been developed to predict the approximate penetration depth into diverse classes of materials for a broad range of energetic incident electrons (\textless 10 eV to \textgreater 10 MeV, with better than 20{\%} accuracy). The penetration depth---or range---of a material describes the maximum distance electrons can travel through a material, before losing all of its incident kinetic energy. This model leads to a predictive formula that estimates the penetration depth for materials without the need for supporting data, but rather using only basic material properties and a single fitting parameter ($N_{v}$, described as the effective number of valence electrons). $N_{v}$ was first empirically calculated for 247 materials which have tabulated range and inelastic mean free path data in the NIST ESTAR and IMFP databases. Correlations of $N_{v}$ with key material constants (atomic number, atomic weight, density, and band gap) were established for this set of materials. These correlations allow prediction of the range for additional materials which have no supporting data. Estimates for both simple compounds ($e.g.$, BnN and AlN) and complex biological materials ($e.g.,$ brain tissue and cortical bone tissue) are presented, along with tests of the validity and accuracy of the predictive formula. These calculations are of great value for studies involving high electron bombardment, such as electron spectroscopy, spacecraft charging or electron beam therapy.

Authors

  • Anne Starley

    Utah State University

  • Gergory Wilson

    Utah State University

  • John Dennison

    Utah State University, Utah State Univ

  • Scott D. Bergesen

    Santa Fe Institute, Arizona State University, Department of Physics and Center for Biological Physics, Arizona State University, Brigham Young University Department of Physics and Astronomy, Brigham Young University, Utah Valley University, Dixie State College, Advisor, Student, Massachusetts Institute of Technology, Thomas Jefferson National Accelerator Laboratory, Colorado College, United States Air Force Academy, Georgia Institute of Technology, Utah State University, Brigham Young University - Idaho, Utah State University- Logan, National Institute of Standards and Technology, Humboldt State University, UC Santa Cruz, Institut de Chimie des Substances Naturelles, Arizona State Univ, University of Colorado at Colorado Springs, National Jewish Health, Department of Physics, The University of Texas at Austin, Department of Physics, New Mexico State University, U. S. Air Force Academy, Brigham Young Univ - Provo, University of New South Wales, University of Texas, University of Warwick, University of Louisiana, Department of Physics and Astronomy, Brigham Young University, Provo, Utah 84602, USA., Center for Materials Genomics, Department of Mechanical Engineering and Materials Science and Department of Physics, Duke University, Durham, North Ca, Duke University, Durham, North Carolina., Brigham Young University -- Provo, Utah, General Atomics -- San Diego, California, Department of Mathematics, University of British Columbia, Department of Physics, Arizona State University, UC Riverside, UMASS, STScI, NOAO, UT Austin, Texas A&M, Arizona State Univeristy, New Mexico State Univ, Los Alamos National Laboratory, Colorado State Univ, Department of Physics, Oregon State University, Colorado School of Mines, University of Alaska, Fairbanks, The Peac Institute of Multiscale Modeling, UNSW Canberra