FLUKA (FLUktuierende KAskade or Fluctuating Cascade) is a general purpose tool for calculations of particle transport and interactions with matter.

FLUKA can simulate, with high accuracy, the interaction and propagation of about 60 different types of particles in matter, including photons and electrons from 1 keV to thousands of TeV, neutrinos, muons of any energy, hadrons of energies up to 20 TeV (up to 10 PeV by linking FLUKA with the DPMJET code) and all the corresponding antiparticles, neutrons down to thermal energies and heavy ions. The program can also transport polarised photons (e.g., synchrotron radiation) and optical photons.

FLUKA can handle even very complex geometries, using an improved version of the well-known Combinatorial Geometry (CG) package. FLUKA can track charged particles in the presence of magnetic or electric fields. It is also possible to describe a complex geometry in terms of "voxels" (tiny parallelepipeds forming a 3-dimensional grid), method that is especially useful when translating a CT scan of a human body into a dosimetry phantom.

Time evolution and tracking of emitted radiation from unstable residual nuclei can be performed online.

More information can be found on the official FLUKA website fluka.cern.

FLUKA is supported by the advanced and user friendly interface Flair (flair.cern), which features a modern and intuitive design and offers a powerful geometry viewer.

For the latest FLUKA release see: https://fluka.cern/download/latest-fluka-release

Advantages & Applications


  • Proton and electron accelerator shielding
  • Target design
  • Calorimetry
  • Activation
  • Dosimetry
  • Detector design
  • Accelerator Driven Systems
  • Cosmic rays
  • Neutrino physics
  • Radiotherapy


The highest priority in the design and development of FLUKA has always been the implementation and improvement of sound and modern physical models. Results are regularly checked against experimental data. As a result, the code has reached a high level of reliability and it provides predictability where no experimental data are directly available.

Another feature of FLUKA is its double capability to be used in a biased mode as well as a fully analogue code. For most applications, no programming is required from the user. However, a number of user interface routines (in Fortran 77) are available for users with special requirements.

  • A friendly user interface is available, as well as a 3D visualisation tool
  • User support is provided through the web site and a dedicated forum
  • Courses for beginners and for advanced users are regularly organised


All relevant specifications and technical aspects of the technology can be found in the online manual of FLUKA.

Developed at
Free for non-commercial use in scientific non-military purposes. For commercial use, see contact person.