Molecular dynamics investigation of threshold displacement energies in CaF2
- Univ. of New Mexico, Albuquerque, NM (United States); Air Force Nuclear Weapons Center, Albuquerque, NM (United States)
- Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
- Idaho National Lab. (INL), Idaho Falls, ID (United States); Canadian Nuclear Lab., Chalk River, ON (Canada)
- Univ. of New Mexico, Albuquerque, NM (United States)
Understanding the propagation of radiation damage in a material is paramount to predicting the material damage effects. To date, no current literature has investigated the Threshold Displacement Energy (TDE) of Ca and F atoms in CaF2 through molecular dynamics and simulated statistical analysis. A set of interatomic potentials between Ca-Ca, F-F, and F-Ca were splined, fully characterizing a pure CaF2 simulation cell, by using published Born-Mayer-Huggins, standard ZBL, and Coulomb potentials, with a resulting structure within 1% of standard density and published lattice constants. Using this simulation cell, molecular dynamics simulations were performed with LAMMPS using a simulation that randomly generated 500 Ca and F PKA directions for each incremental set of energies, and a simulation in each of the [1 0 0], [1 1 0], and [1 1 1] directions with 500 trials for each incremental energy. MD simulations of radiation damage in CaF2 are carried out using F and Ca PKAs, with energies ranging from 2 to 200 eV. Probabilistic determinations of the TDE and Threshold Vacancy Energy (TVE) of Ca and F atoms in CaF2 were performed, as well as examining vacancy, interstitial, and antisite production rates over the range of PKA energies. Many more F atoms were displaced from both PKA species, and though F recombination appears more probable than Ca recombination, F vacancy numbers are higher. In conclusion, the higher number of F vacancies than Ca vacancies suggests F Frenkel pairs dominate CaF2 damage.
- Research Organization:
- Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)
- Sponsoring Organization:
- USDOE National Nuclear Security Administration (NNSA)
- Grant/Contract Number:
- AC04-94AL85000
- OSTI ID:
- 1574439
- Alternate ID(s):
- OSTI ID: 1778344
- Report Number(s):
- SAND--2019-12521J; 680417
- Journal Information:
- Computational Materials Science, Journal Name: Computational Materials Science Journal Issue: C Vol. 172; ISSN 0927-0256
- Publisher:
- ElsevierCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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