Primary Radiation Damage in Materials: Review of Current Understanding and Proposed New Standard Displacement Damage Model to Incorporate in Cascade Defect Production Efficiency and Mixing Effects

This report reviews the current understanding of primary radiation damage from neutrons, ions and electrons (excluding photons, atomic clusters and more exotic particles), with emphasis on the range of validity of the “displacement per atom” (dpa) concept in all major classes of materials with the exception of organics. The report also introduces an “athermal recombination-corrected dpa” (arc-dpa) relation that uses a relatively simple functional to address the well-known issue that “displacement per atom” (dpa) overestimates damage production in metals under energetic displacement cascade conditions, as well as a “replacements-per-atom” (rpa) equation, also using a relatively simple functional, that accounts for the fact that dpa is understood to severely underestimate actual atom relocation (ion beam mixing) in metals.