SCONE Guide
SCONE Verification Notice
SCONE is a research-oriented code with a smaller user base than MCNP, OpenMC, or SERPENT. Our examples are intended as educational guidance. For authoritative syntax, physics options, and nuclear data requirements, consult the official documentation.
Neutron Transport in SCONE
Simulating Neutron Movement and Interactions
Transport Fundamentals
Neutron transport simulation tracks particles as they move through materials and undergo various interactions. SCONE offers multiple tracking methods, each with advantages for different problem types. Surface tracking excels in geometries with well-defined boundaries, while delta tracking can be more efficient for homogeneous regions.
collisionOperator { neutronCE { type neutronCEstd; } }
transportOperator { type transportOperatorDT; }The collisionOperator block configures how neutron collisions are handled. neutronCE with type neutronCEstd provides standard continuous-energy collision physics. The transportOperator block selects the tracking method: transportOperatorDT for delta tracking or transportOperatorST for surface tracking.
Delta Tracking vs Surface Tracking
Delta tracking (DT) samples distances to the next collision using the total cross section and uses virtual collisions at material boundaries. It avoids explicit surface crossings and can be efficient for complex heterogeneous geometries. Surface tracking (ST) explicitly tracks particles from surface to surface, which can be preferable when boundaries are well-defined and surface crossings are frequent.
collisionOperator { neutronCE { type neutronCEstd; } }
transportOperator { type transportOperatorST; }To use surface tracking instead of delta tracking, change transportOperatorDT to transportOperatorST. The collision operator remains the same.
Full Input Context
The transport and collision operators are specified at the top level of the input, alongside the physics package type and population parameters.
type eigenPhysicsPackage;
pop 100000;
active 300;
inactive 200;
XSdata ce;
dataType ce;
collisionOperator { neutronCE { type neutronCEstd; } }
transportOperator { type transportOperatorDT; }Best Practices
Choose tracking methods based on your geometry complexity and material distributions. Delta tracking is often preferred for reactor core problems with many material interfaces. Surface tracking may perform better for simpler geometries with few surfaces. Test transport settings with simplified problems before scaling to full complexity.
Next Steps
With transport settings configured, you'll want to measure specific quantities in your simulation. The Tallies section explains how to define detectors, score reaction rates, and analyze results.