Improving atomic displacement and replacement calculations with physically realistic damage models

Area of Science:

• Materials Science
• Nuclear Engineering
• Condensed Matter Physics

Background:

• Atomic collision processes are crucial for advanced technologies like electron microscopy, semiconductor fabrication, and nuclear energy.
• The Norgett-Robinson-Torrens displacements per atom (NRT-dpa) model is the current standard for quantifying energetic particle damage.
• The NRT-dpa model has known limitations, underestimating defect production and overestimating atomic mixing.

Purpose of the Study:

• To address the limitations of the NRT-dpa model in accurately quantifying radiation damage.
• To introduce new, more physically realistic estimators for primary defect creation and atomic mixing.
• To propose complementary measures for enhanced radiation damage assessment in materials.

Main Methods:

• Development of new displacement production estimators, specifically athermal recombination corrected displacements per atom (arc-dpa).
• Formulation of new atomic mixing estimators, termed replacements per atom (rpa).
• Comparison and extension of existing NRT-dpa model calculations.

Main Results:

• The number of radiation defects produced in energetic cascades is approximately 1/3 of the NRT-dpa prediction.
• The number of atoms involved in atomic mixing is about 30 times larger than predicted by the dpa value.
• The proposed arc-dpa and rpa functions provide more accurate descriptions of primary defect creation and atomic mixing.

Conclusions:

• The proposed arc-dpa and rpa functions offer more physically realistic descriptions of radiation damage compared to the NRT-dpa model.
• These new estimators can serve as additional standard measures for quantifying radiation damage in materials.
• Improved quantification of radiation damage is essential for advancing materials technologies in various fields.