Release of FLUKA 4-3.0

Dear FLUKA users,

It is our pleasure to announce that a new major release of the FLUKA code, version 4-3.0, 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 new features, among which we wish to highlight the availability of a novel point-wise treatment for neutron interactions below 20 MeV. Please observe that in order to benefit from this feature, further packages need to be downloaded and installed, as detailed in this page

In the latest version of the Mac OSX operating system, gfortran8 is no longer supported. We have therefore stopped the distribution of the gfortran8 FLUKA binary package for Mac.

To profit from the new features, please update to the latest version of Flair available in the Official Flair site.

With our kindest regards,

The FLUKA developer team at CERN and Collaborating Institutes

=== Fluka-4.3.0 ===

This major release contains several physics improvements, as well as the further technical improvements and notable bug corrections listed below. Among the former ones, the inclusion of a novel point-wise treatment for low-energy neutron interactions (below 20 MeV) should be particularly highlighted, since it overcomes a longstanding lack and considerably extends the applicability of the code.

The code manual has been recast in restructured text format, providing the user with three consistent versions: text, pdf, and html.


  • A new point-wise treatment has been developed for the interactions of low-energy neutrons (below 20 MeV), relying on the Evaluated Neutron Cross Section Libraries for the Geant4 code.

    The pre-existing group-wise treatment remains available by default and can be adopted in mixed group- and point-wise calculations.

    The LOW-PWXS card enables the new treatment on an elemental material basis, allowing the user to select among the full isotope list in the various neutron libraries to be downloaded from this page.

    The same card offers the possibility to apply Doppler broadening at arbitrary temperatures and to request S(alpha,beta) treatment to account for molecular binding effects.
    As opposed to the group-wise treatment, reaction products - including residuals - are explicitly generated in a correlated manner. Fission fragments are sampled from the library or, if missing, by means of the Wahl systematics.

    Special attention has been devoted to minimize the intrinsic CPU cost.

  • The code is now aligned with the latest DPMJET v19.3.2, which fixed spurious features in kaon spectra from nucleus-nucleus collisions at energies of ~10 GeV/n.

  • Scoring of athermal-recombination-corrected displacements per atom (arc-DPA) has been added, following Eqs. 6-7 of

    K. Nordlund et al., Nature Communications 9 1084 (2018),

    requiring two new user-specified parameters, as detailed in the MAT-PROP card documentation.

    Generalized particle DPA-NRES (#245) has been deprecated and replaced by the Norgett-Robinson-Torrens DPA-NRT.

  • The emission of synchrotron radiation photons along charged particle steps, in vacuum regions subject to a magnetic field, has been implemented and can be requested with the dedicated SYRASTEP card. Note that the related SYNC-R… options of SPECSOUR remain available, although they may be more naturally and effectively superseded by the use of the former.

  • Mass distribution of 226Ra fission fragments was corrected, addressing this forum post.


  • The new DETGEB card allows the user to apply a Gaussian broadening to energy deposition spectra scored with the DETECT card.

  • The maximum number of regions of interest (ROI) in voxel geometries has been increased from 100 to 400.

  • In the source_newgen.f user routine, sampling from a spectrum file (energy, intensity) was added.


  • Fixed faulty branchings for Auger, XR and CE radiation products in decays of the following nuclides/isomers

    • 83mKr, 94mNb, 132mI, 138mCs, 151mTb, 164mHo, 205mPb
    • 57Mn, 101Mo, 105Sn, 111Pd, 120Xe, 123Cs, 174Ta, 228Ra, 230Pa, 247Cf addressing this forum post.
  • Unphysical forward/backward CM asymmetry in symmetric nucleus-nucleus collisions simulated by DPMJET was removed.

  • A sampling bug in the original synchrotron radiation special source was fixed.

  • In the source_newgen.f user routine, unexpected behaviour for annular sampling was fixed.