Molecular Dynamics Study of Radiation Damage Cascades in BCC Iron
A completed molecular-dynamics study of how PKA energy, crystal direction, and temperature affect short-time radiation-damage cascades in perfect BCC alpha iron.
Software compatibility
The source, retained trajectories, and verified results use LAMMPS 7 Feb 2024 Update 1 with the tersoff/zbl pair style. Other LAMMPS releases and molecular-dynamics packages are not verified.
Project definition
Problem statement
An energetic recoil atom can displace iron atoms and leave vacancies, interstitials, and small defect clusters. The outcome depends on recoil energy, crystal direction, temperature, potential choice, timestep control, boundary treatment, and the defect-counting method.
The physics problem is to run a controlled factor study, retain every trajectory, identify defects consistently, and separate peak collision damage from the defects that survive prompt recombination.
Project objectives
- Build and equilibrate a perfect BCC alpha-iron cell containing 11,664 atoms.
- Compare 250, 500, and 1000 eV primary knock-on atoms along [100], [110], and [111].
- Repeat the complete energy and direction matrix at 300 K and 600 K.
- Measure peak and surviving Frenkel pairs, defect clusters, cascade radius, and physical time.
- Compare the atomistic survivor counts with the analytical NRT displacement estimate.
Project structure
Project components
Case generator
Creates the exact 18-case factor matrix, LAMMPS inputs, metadata, and launch velocities.
LAMMPS simulation
Runs minimisation, equilibration, adaptive collision dynamics, and the boundary heat sink.
Defect analysis
Uses periodic nearest-site occupancy to count vacancies, interstitials, Frenkel pairs, clusters, and radius.
Evidence pipeline
Retains compressed trajectories, logs, final structures, CSV tables, JSON summaries, and figures.
Verification
Checks launch energy, atom conservation, physical duration, final plateaus, documents, and software quality.
Methodology
Project workflow
- 01Prepare the cell
The code builds the BCC lattice, verifies the potential checksum, and creates one case directory per factor combination.
- 02Equilibrate
LAMMPS minimises the lattice and equilibrates it at 300 K or 600 K.
- 03Launch the PKA
One central iron atom receives the exact configured recoil energy and crystal direction.
- 04Run and retain
Adaptive molecular dynamics records thermodynamics, coordinates, local structure, and final states.
- 05Analyse and compare
The project rebuilds defect tables and figures, then compares energy, direction, temperature, and NRT trends.
Demonstration scenario
The complete matrix is rebuilt from one configuration. The student compares the maximum peak of 48 Frenkel pairs with the final survivor range of 1 to 6 pairs, explains prompt recombination, examines direction and temperature differences, and traces every plotted result back to its retained LAMMPS case.
Engineering
Tools and method
- Tools
- The project uses LAMMPS 7 Feb 2024 Update 1, Python 3.11, NumPy, Pandas, SciPy, Matplotlib for subject analysis, simulation, and results.
- Atomistic engine
- LAMMPS performs BCC iron dynamics with the retained Byggmastar and Granberg Fe tersoff/zbl potential.
- Experiment control
- Python generates, resumes, validates, and analyses the complete 18-case matrix.
- Numerical control
- Adaptive timesteps limit atomic motion and kinetic-energy change during close collisions.
- Analysis
- NumPy, Pandas, SciPy, and Matplotlib produce time histories, factor summaries, and labelled figures.
- Reproducibility
- Docker, exact inputs, checksums, tests, raw evidence, Word files, and PDFs support independent reruns.
Testing
Evaluation
Evaluation measures
- Exact PKA count and launch energy for all eighteen cases
- Peak and final Frenkel-pair counts across energy, direction, and temperature
- At least 5 ps total physical time and a 3 ps final-count plateau in every case
- Balanced final vacancy and interstitial counts in the periodic cell
- Defect-survival fraction, cluster size, cascade radius, and NRT comparison
- Automated tests, coverage, dependency audit, document checks, and retained raw evidence
Project boundaries
- The model represents perfect BCC alpha iron under one interatomic potential and one thermal seed per factor cell.
- The selected 250 to 1000 eV range studies low-energy primary damage and does not represent a full reactor recoil spectrum.
- All conclusions concern picosecond defect production and survival, not long-time diffusion, accumulated dose, alloy response, or component life.
- Electronic stopping, grain boundaries, dislocations, alloy chemistry, experimental validation, and property prediction are outside the completed scope.
Included
- 01Complete Python and LAMMPS source code
- 02Eighteen completed simulations with 11,664 atoms per case
- 03Eighteen compressed trajectories, logs, inputs, and final structures
- 04Exact iron potential file with a verified checksum
- 05Nine hundred and eighteen analysed trajectory frames
- 06Twenty-two labelled theory, method, literature, and result figures
- 07Fifty-five automated tests with 94 percent coverage
- 08Complete project files, calculations, results, and analysis material in a private GitHub repository
- 0974-page project documentation in PDF and editable Word formats
- 1013-page setup and usage guide in PDF and editable Word formats
- 11Fifty annotated references with literature-image provenance
Project record
No information is collected on this page.
- Permanent project ID
- GP-PH-0F2RQC4
- Catalogued
- 21 Aug 2026
- Completed
- 26 Aug 2026
- Verified
- 26 Aug 2026
- Demonstration
- Included in repository
Handover
After purchase
- 01Payment is confirmed
The project is marked unavailable and cannot be purchased again.
- 02Repository access is granted
The buyer's submitted GitHub account receives access to the private repository.
- 03The purchase record is delivered
The certification sheet is prepared from the reviewed buyer details and sent privately by email.