==== Release notes for Fluka2024.1 ,  ====

==== the 4th generation of the FLUKA ====

==== MC code, authored by A.Fassò,  ====

==== A.Ferrari, J.Ranft, and P.R.Sala   ====

his is a major release with several important physics and technical improvements and additions.

New features are shortly listed below, and described in more detail in the following of these release notes, and in the manual.

SHORT LIST OF NEW/CHANGED FEATURES

• Pointwise Thermal Scattering Laws (TSL) for thermal neutrons implemented, including inelastic scattering (S(alpha,beta)), incoherent elastic, and coherent elastic;
• Libraries for TSL for a few elements/temperatures/compounds available in the pointwise library;
• Coherent (Rayleigh) photon scattering: now performed accounting also for the real, f_1, and imaginary, f_2, anomalous form factors, in coherence with how the EPICS cross sections are calculated;
• X-ray complex refraction indeces implemented. X-ray reflection from thick mirrors implemented using the complex refraction indeces;
• Photonuclear interactions: further improvements in models above ~100 MeV;
• Hadronisation model: fully reworked in order to better account for experimental data which somewhat contradict widely accepted assumptions about string hadronization;
• GDR cross sections updated and revised for 238U;
• Built-in source routines for neutron spectra from D-D and D-T thick target sources (see the BEAM card);
• Updated galactic cosmic ray spectra: now based on AMS02 data, they can be activated by new option in SPECSOUR : sdum = GCR-AMS;
• Built-in source routines for neutron spectra from Am-Be, Am-B, 252-Cf sources (see the BEAM card);
• Nuclear levels decaying only by Internal Conversion are now treated as stable for in-flight decay. They decay when the ion comes at rest;
• Interface CORSIKA7/8: further expanded and improved;
• Further Source code reorganization.
At the same time a few rare bugs have been fixed, and an issue with a too small array dimension found by our GSI colleagues fixed as well.

EXTENDED DESCRIPTION OF NEW FEATURES

• Pointwise, fully continuous, thermal neutron scattering kernels are now implemented for several isotopes in specific compounds at specific temperatures. FLUKA supports fully continuous energy-angle inelastic scattering (S(alpha,beta)), fully continuous angle incoherent elastic, and Bragg like coherent elastic. The databases (available as usual in the pwxs/ folder) have been processed out of Endf/b-8r0 using Acemaker or Njoy2016 to produce ACE format files, which are then offline postprocessed into a FLUKA specific format. Several isotope/material /temperatures are already available (look for *-tsl-* files inside pwxs/) others will come. Argon at 87K is also available from a special evaluation. The new pointwise TSL treatment can be activate by using the TSL-PWXS card (see the manual for details);
• The real, f_1, and imaginary, f_2, anomalous form factors are now used as provided by EPICS2017;
  1. they are used in photon coherent (Rayleigh) scattering, so that now the scattering angular distribution is fully coherent with the integrated cross section as obtained by EPICS2017. The change is significant in some energy ranges;
  2. f_1 and f_2 are also used in order to compute the complex refraction indeces of X-rays.
• TThe X-ray complex refraction indeces are used in order to compute reflection probabilities for X-rays on thick mirrors, as a function of the incidence angle. X-ray reflection can be activated using the MAT-PROP card with sdum=X-REFLEC (see the manual for further details);
• Photo-nuclear interactions in the resonance region (0.1-1 GeV) have been further improved, particularly concerning 2-nucleon and 3-nucleon absorption channels;
• GDR photonuclear cross sections have been updated for 238U;
• Built-in source routines for neutron spectra from D-D and D-T thick target sources are now available, besides those for Am-Be, Am-B, 252-Cf (see the BEAM card);
• Nuclear transition decaying only by Internal Conversion decays (IC) are not longer stepped multiple times while in flight according to their mean life only to discover that they cannot decay for lack of atomic electrons. Now they are treated as stable until the ion comes to rest and electrons are available for the IC decay;
• The source code has been deeply reorganised and streamlined. is no longer used by any of the interaction routines;

WARNING

ALWAYS VALID IMPORTANT WARNINGS

• Whenever residual nuclei (and residual dose rates) scoring is of importance, or accurate neutron yields are required, the heavy residual emission ("fragmentation") and the coalescence emission of fast complex particles should be switched on, through the following data cards:
  PHYSICS 3.0 EVAPORAT
  PHYSICS 1.0 COALESCE
  and (as a consequence of coalescence) it would be wise to link with rQMD-2.4 (and DPMJET) and activate ion transport and interactions, and circumvent the lack of deuteron interactions at low energy with
  PHYSICS 1.0 0.005 0.15 2.0 2.0 2.0IONSPLIT
  These suggestions are mandatory for residual nuclei calculations.
• Old residual nuclei output files The auxiliary programs (usrsuw and usrsuwev in $FLUPRO/flutil) that sum and process the residual nuclei output files depend on the nuclear database. Users who still need to process files produced with previous fluka versions should contact the fluka developers. Users who already produced xxx_tab.lis and xxx_sum.lis files are not concerned.
• The ARB, BOX, WED body types, which are deprecated since many years due to their precision problem prone coding, are now accepted only if the user explicitly sets SDUM=DEPRBODY in the GLOBAL card.
• The use of so-called "expressions" inside the Flair preprocessor, those writing pseudo-comments in the input file like !@what.1=-1.5e-2is deprecated. In order to still use those kind of expressions, the user has to explicitly set SDUM=OLDFLAIR in the GLOBAL card.

REFERENCES TO BE QUOTED

The use of the FLUKA code must be acknowledged explicitly by quoting at least the following set of references

• F. Ballarini, G. Battistoni, N. Belcari, G. Bisogni, M. Campanella, M.P. Carante, G. Dedes, P. Degtiarenko, P. de la Torre Luque, R. dos Santos Augusto, A. Fasso`, A. Fedynitch, Alfredo Ferrari, Anna Ferrari, E. Fiorina, G. Kharashvili, A. Kraan, G. Magro, A. Mairani, I. Mattei, M.N. Mazziotta, M.C. Morone, S. Mueller, S. Muraro, K. Parodi, V. Patera, F. Pennazio, L.S. Pinsky, R. Rachamin, R. Luis Ramos, S. Rollet, P.R. Sala, M.S. Leitner, L. Sarchiapone, T. Tessonnier, K. Smeland Ytre-Hauge, L. Zana, "FLUKA: status and perspectives", Proceedings of the "15th Workshop on Shielding Aspects of Accelerators, Targets, and Irradiation Facilities" (SATIF-15), East Lansing, Michigan, USA, September 20-23, 2022, in press
• A. Ferrari, P.R. Sala, A. Fasso`, and J. Ranft,
  "FLUKA: a multi-particle transport code",
  CERN 2005-10 (2005), INFN/TC_05/11, SLAC-R-773

Use of Flair must be acknowledged using the following reference:

• V. Vlachoudis,
  Proc. Int. Conf. on Mathematics, Computational Methods & Reactor Physics (M&C 2009),
  Saratoga Springs, New York, 2009

Additional FLUKA references can be added, provided they are relevant for this FLUKA version.

The use of the neutrino event generator (NUNDIS) must be acknowledged by quoting

• G. Battistoni, A. Ferrari, M. Lantz, P. R. Sala and G. I. Smirnov,
  "A neutrino-nucleon interaction generator for the FLUKA Monte Carlo code",
  Proceedings of 12th International Conference on Nuclear Reaction Mechanisms,
  Varenna, Italy, 15-19 June 2009,
  CERN-Proceedings-2010-001 pp.387-394.
  

For medical applcations of FLUKA:

• G. Battistoni, J. Bauer, T.T. Boehlen, F. Cerutti, M.P.W. Chin, R. Dos Santos Augusto, A. Ferrari, P.G. Ortega, W. Kozlowska, G. Magro, A. Mairani, K. Parodi, P.R. Sala, P. Schoofs, T. Tessonnier, V. Vlachoudis,
  "The FLUKA code: An accurate simulation tool for particle therapy",
  Frontiers in Oncology, Radiation Oncology Section, 00116 (2016)

If FLUKA is used together with rQMD-2.4 or DPMJET-3 the following references should be quoted:

rQMD-2.4:

• H. Sorge, H. Stoecker, and W. Greiner, Annals of Physics 192, 266 (1989)
• V. Andersen. F. Ballarini, G. Battistoni, M. Campanella, M. Carboni, F. Cerutti, A. Empl, A. Fasso`, A. Ferrari, E. Gadioli, M.V. Garzelli, K. Lee, A. Ottolenghi, M. Pelliccioni, L.S. Pinsky, J. Ranft, S. Roesler, P.R. Sala, and T.L. Wilson,
  "The FLUKA code for space applications: recent developments",
  Advances in Space Research, 34(6), 1302-1310 (2004).

DPMJET-3:

• S.Roesler, R.Engel, J.Ranft: "The Monte Carlo Event Generator DPMJET-III"
  in Proceedings of the Monte Carlo 2000 Conference, Lisbon, October 23-26
  2000, A. Kling, F. Barao, M. Nakagawa, L. Tavora, P. Vaz eds.,
  Springer-Verlag Berlin, 1033-1038 (2001).
• A. Fedynitch, PhD Thesis, https://cds.cern.ch/record/2231593/files/CERN-THESIS-2015-371.pdf.

EXTRA FEATURES FOR FLUKA2021.2.9

Starting with Fluka2021.2.9 the low energy neutron cross sections for a few extra isotopes are available in both the groupwise and pointwise neutron libraries, specifically, 226Ra, 227Ac, 231Pa, 233Pa, 237Np, 239Np.

Please refer to the manual for further informations about how to access those cross sections data sets

EXTRA FEATURES FOR FLUKA2021.2.7

Starting with fluka2021.2.7, the description of hadron-nucleon intranuclear cascade reinteractions in Dpmjet3x (see below) can now optionally be performed with the Fluka hadron-nucleon interaction models, rather than the old hadrin model contained in Dpmjet3x.

This is not yet the default (it will soon become the default): in order to activate this important feature, please include a DPMJET card with

WHAT(6)=1 or 10 or 11
• 1 = nonelastic hadron-nucleon reinteractions managed by Fluka routines
• 10 = elastic hadron-nucleon reinteractions managed by Fluka routines
• 11 = both elastic and nonelastic hadron-nucleon reinteractions managed by Fluka routines (recommended)

Also starting with fluka2021.2.7 a new version of Dpmjet3, Dpmjet3.19.3, is available (only for the gfortran based releases). This new release (thanks to A.Fedynitch) introduces several improvements, streamlines the interface with Fluka making its maintenance much easier, and it greatly improves the issues with Kaon production in AA collisions below 10-20 GeV/n.

The possibility of using Fluka hadron-nucleon interaction models for reinteractions (described in the first point) applies both to the "old" Dpmjet3.17 and the "new" Dpmjet3.19.3.

In order to link the new Dpmjet version, please use the script flutil/ldpmqmdnw instead of flutil/ldpmqmd, and use the resulting executable which is called by default flukadpmnw.

For the time being both the "old" and "new" Dpmjet versions are available (gfortran releases), in the future only the new one will be distributed.

Release notes for Fluka2021.2 -

This is a major release with several important physics and technical improvements and additions..

New features are shortly listed below, and described in more detail in the following of these release notes, and in the manual.

Some of the features require modifications of the users routines please read carefully if you have any.

If you are using the tar files rather than the rpm's, please note that you have to download two files since now all data libraries, which are common to all compilers/architectures are now provided in a separate file (see below and the README file)

SHORT LIST OF NEW/CHANGED FEATURES

• Pointwise transport of low energy neutrons with correlated interactions is now available. A separate data file has to be downloaded (see README)
• Runge-Kutta based transport in electric fields is implemented for vacuum and gas regions
• Optional Runge-Kutta based transport in magnetic field in vacuum and gas regions
• New physics model for coherent elastic scattering of hadrons on nuclei
• New treatment for quasi-elastic scattering of hadrons on nuclei
• Transport and in-flight decay of excited residual nuclei
• Improved nuclear mass/decay/deexcitation database
• Revised hadron-nucleus interaction cross sections
• Revised cross sections for proton - light ion interactions
• Non monochromatic scintillation light emission and transport
• Delta resonance decay in photon+nucleon

NEEDED MODIFICATIONS TO USER ROUTINES

• magfld.f has one more argument: time
• source.f variables related to in-flight transport have to be initialized
• mgdraw.f entry USDRAW: pay attention to quasielastic, flags available (see below)
• mgdraw.f entry USDRAW: new interaction code for ion splitting events
• new routines for non-monochromatic scintillation light (see manual)

-- EXTENDED DESCRIPTION OF NEW FEATURES --

• Pointwise transport of low energy neutrons. This brand new feature, a major improvement in FLUKA capabilities, includes both the "continuous" transport of neutrons, and the generation of interaction products with a mixed data and model driven treatment fully conserving energy event-by-event. Pointwise transport is available as an option, the group-wise transport is still the default. Hybrid simulations are also possible. Pointwise cross sections are activated through a new card:
  LOW-PWXS
  Details are available in the manual.
  When neutron pointwise transport is activated, it is also possible to set-up estimators with equidistant (linear or logarithmic) energy intervals, without the usual groupwise structure. See the description of the relevant scoring card in the manual. IMPORTANT WARNING: to save space and bandwidth, all data libraries for nuclear data, photon data, and neutron and pointwise cross sections are NOT included in the fluka tar files. They have to be downloaded separately, and placed in the same $FLUPRO directory as the rest of the distribution. A consistency check between Fluka version and data file version is automatically performed.
• Transport in electric field is implemented in vacuum and gas. A new card
  ELEFLD
  activates it in selected regions, as flagged through the ASSIGNMAT card. A new user routine,
  elefld.f
  is available for providing non-uniform fields. Time-varying fields can also be implemented through this user routine. Combined electric and magnetic fields are supported. Transport is performed according to a Runge-Kutta treatment. In case of transport in gas, single scattering is automatically activated. See the manual for details.
• Transport in non uniform magnetic fields through the same Runge-Kutta algorithm is available as an option for vacuum and gas regions (it is used by default if an electric field is also present) by using
  SDUM=RUNGKUTT in the MGNFIELD card.
  The Runge-Kutta algorithm is signficantly more accurate than the traditional one for the same CPU time, or it is faster for the same accuracy. See the manual for details.
• New algorithm for coherent elastic scattering of hadrons on nuclei. A general model from combining black disk scattering and grayness has been derived for FLUKA. Parameters of the model for p and n up to 200 MeV have been fitted to distributions available in ENDF/B-8R0 and JENDL40-HE. Experimental data have been used to set the model parameters above 1 GeV. Scaling and interpolation of parameters are used for combinations where no data is available. The new algorithm is applied to protons and neutrons up to 200 MeV, and to all hadrons from 1 GeV upwards. Only for 4He, 12C, 16O, 208Pb the model is applied for protons and neutron scattering over the whole energy range.
• Quasi elastic interactions (above few GeV): quasi-elastic are interactions where the projectile scatters elastically on one of the target nucleons. Traditionally, those interactions are considered as nonelastic one at low energies. As energy increases, they are less and less experimentally distinguishable from coherent elastic scattering. In FLUKA, high energy quasielastic was included up to now in the elastic scattering treatment, without production of secondaries. Since Fluka2021, quasielastic has its own treatment, including production of secondary particles from nuclear de-excitation. For users implementing their own scoring of interactions: please be aware of this difference with respect to the past. Quasielastic are now flagged in USDRAW with the same code as inelastic (101). They carry as .true. the flag LELEVT in (EVTFLG) and the flag LQEEVT in (NUCFLG).
• In-flight decay of excited residual nuclei. Excited nuclei with measurable/known mean life will not de-excite during the nuclear interaction which produced the excited state, but rather will fly until decay according to the level mean life. This has consequences for instance at very high energies, with nuclei potentially decaying far from the production point, and for Doppler broadening of gamma lines. In-flight decay can be activated/deactivated with the
  PHYSICS card, SDUM=INFLDCAY.
  It is on by default with the PRECISIO and HADROTHE defaults.
• The nuclear properties database has been upgraded, in particular with the update of nuclear masses to the newest compilation, AME 2020.
• A full revision of hadron-nucleus cross sections, in particular for nucleons and pions in the 1-20 geV energy range, has been carried out
• Cross sections for interactions of very light ions, mass 3 and 4 on hydrogen (and for the inverse kinematic reaction) have been greatly improved.
• The possibility to genarate and transport optical photon from non-monochromatic scintillation lines is now available. New user routines have to be edited to provide spectrum and intensity of scintillation lines: sphspc.f and usfsci.f. They can be activated through the OPT-PROD card (see manual for details)
• Decay of the Delta(1232) resonance in photon+nucleon is now simulated. The branching ratio (small) depends on the actual Delta mass.

Last updated: 5th of May, 2024