Particle transport · Nuclear data
General nuclearScientific computing

Geant4.

Geometry and Tracking Toolkit

Geant4 is a C++ toolkit for Monte Carlo simulation of particles and radiation passing through matter: the user describes geometry and materials, chooses a physics list, fires primaries, and Geant4 tracks every particle and its secondaries through electromagnetic, hadronic, decay and optical processes from thermal-neutron energies up to the TeV range. It ships navigation, field tracking, scoring, visualisation, multithreading and a large set of example applications.

Runs in the HubListedSources checked 2026-10-10
Engineering questions it helps answer
  • How much energy is deposited, and what dose is received, in a volume behind a shield or inside a detector for a given source?
  • What secondary particle fluxes and spectra emerge from a target or structure, and how do they change with material and thickness?
  • Which radionuclides are produced in a component by a hadronic cascade, and how does their activity evolve?
Physics scope
  • Electromagnetic physics for electrons, positrons, photons, muons, hadrons and ions
  • Hadronic physics with inelastic and elastic models and cross-section data
  • High-precision neutron transport (neutronHP, G4NDL) with thermal scattering
  • Radioactive decay and activation
  • Optical photons; CSG and GDML geometry; field tracking
  • Scoring, sensitive detectors, analysis output; event-level multithreading

Limitations

A toolkit, not a ready-to-run program: users write and build their own C++ application. The licence is a custom Geant4 Software License rather than a standard OSI text. The collaboration publishes no official container image, large data sets are separate downloads, and results depend on the chosen physics list and data.

Fusion relevance

A general-purpose particle-transport toolkit whose official pages do not describe it as fusion-specific. Its relevance is indirect: thermal-to-fast neutron transport with the high-precision neutron package and bundled neutron data, energy-deposition and activation examples, and the freedom to build a custom application around a 14 MeV source term. Any fusion workflow is built by the user on top of the toolkit.

Distribution note

Primary development is on CERN GitLab; the GitHub repository receives release imports and accepts pull requests.

Upstream examples

Published by the project itself. These are the project's own tutorials, not Morton Labs runs.

Reference workflows on this site

No reference workflow documents this tool yet. Its evidence status is “Listed”: A reviewed catalog entry with upstream links.

People

Developed by The Geant4 Collaboration, an international collaboration of laboratories and institutes with its website and source hosting at CERN. No individual profiles are published for this project yet.

Roles name a specific relationship with evidence. Authorship of a paper is not maintainership, and a listed person is not a Morton Labs partner or endorser.

Source collections

This entry was written by Morton Labs from public sources and last checked on 2026-10-10. Spotted an error, or want something changed or removed? Email zach@mortonlabs.ai with the page address.

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