Release of FLUKA 4-3.3

Dear FLUKA users,

It is our pleasure to announce that a new minor release of the FLUKA code, version 4-3.3, has been issued and can be downloaded from the Official CERN FLUKA website:

See the release notes at the bottom of this message for a detailed account of all novelties, among which we highlight an updated package for JEFF-3.3 pointwise interactions of neutrons below 20 MeV, now embedding improved S(a,b,T) thermal scattering law tabulations. This new package (which supersedes the package offered hitherto) must be explicitly downloaded from

For consistency, please update to the latest version of Flair, available from:

With our kindest regards,

The FLUKA developer team at CERN and Collaborating Institutes


=== Fluka-4.3.3 ===



  • Fixed a crash (kindly reported by BNL colleagues), whereby a low-energy 197Au+56Fe collision via the BME complete fusion module yielded a transuranic residual nucleus with Z>100 above transport threshold, whose reaction cross section in hydrogen failed to evaluate.

  • Fixed a bug which led to Gaussian energy broadening erroneously applied after events with no energy deposition.

  • Point-wise neutron interactions:

    • For events involving the combined emission of neutrons as well as charged particles, the neutron is now sampled first, thus assuring a more faithful adherence to the inclusive neutron emission spectra of the database.

    • Improved sampling from energy/angle tabular distributions for channels containing different interpolation schemes for various energy intervals.

    • Fixed a bug affecting the Kalbach-Mann slope calculation when not available in the database.