What is Geant4?

Geant4 is a software toolkit for the simulation of the passage of particles through matter, widely used in high energy physics, nuclear experiments, and medical physics. It allows scientists and engineers to model how particles interact with complex geometries and materials, helping to design detectors and optimize experiments. Written in C++, Geant4 provides a flexible and extensible framework for simulating physics processes such as electromagnetic, hadronic, and optical interactions. The toolkit is developed by an international collaboration and is open-source, making it accessible to researchers around the world.