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DEFAULTS

sets FLUKA defaults suitable for a specified kind of problems. Starting from FLUKA99.5 (June 2000) the standard defaults are those described under NEW-DEFAults below. That is, if no DEFAULTS card is issued the code behaves as if a card with NEW-DEFAUlts was given.

See also GLOBAL

Important: DEFAULTS declarations, if present, must precede any executable option

     WHAT(1),....,WHAT(6): not used

     SDUM = CALORIME : defaults for calorimeter simulations
            EET/TRAN : defaults for Energy Transformer or transmutation
                       calculations
            EM-CASCA : defaults for pure EM cascades
            ICARUS   : defaults for studies related to the ICARUS experiment
            HADROTHE : defaults for hadrotherapy calculations
            NEUTRONS : defaults for pure low-energy neutron runs
           [NEW-DEFA : reasonable minimal set of new defaults - not needed]
            PRECISIO : defaults for precision simulations
            SHIELDIN : defaults for hadron shielding calculations without gammas

     Default: it is not allowed to leave SDUM blank. If the DEFAULTS card is
            missing, the standard defaults are unchanged (equivalent to setting
            SDUM = NEW-DEFAults)

Defaults changed by the various options:

CALORIMEtry

• EMF on (no need for an EMF card)

• Rayleigh scattering and inelastic form factor corrections to Compton scattering and Compton profiles activated (no EMFRAY needed)

• Detailed photoelectric edge treatment and fluorescence photons activated (no EMFFLUO needed)

• Low-energy neutron transport on (no LOW-NEUT needed) down to thermal energies included. High energy neutron threshold at 20 MeV.

• Fully analogue absorption for low energy neutrons

• Particle transport threshold set at 1 x m_part / m_prot MeV, except for neutrons (thermal), and (anti)neutrinos (0, but they are discarded by default anyway)

• Multiple scattering threshold at minimum allowed energy, for both primary and secondary charged particles

• Delta ray production on with threshold 100 keV (see option DELTARAY)

• Restricted ionisation fluctuations on, for both hadrons/muons and EM particles (see option IONFLUCT)

• Fraction of the kinetic energy to be lost in a step set at 0.08,
  number of dp/dx tabulation points set at 80 (see options DELTARAY,
  EMFFIX, FLUKAFIX)

• Heavy particle e+/e- pair production activated with full explicit production (with the minimum threshold = 2 m_electron)

• Heavy particle bremsstrahlung activated with explicit photon production above 300 keV

• Muon photonuclear interactions activated with explicit generation of secondaries

• Heavy fragment transport activated

EET/TRANsmutation

• Low energy neutron transport on down to thermal energies included (high energy neutron threshold at 20 MeV)

• Non-analogue absorption for low energy neutrons with probability 0.95 for the last (thermal) groups

• Particle transport threshold set at 1 MeV, except neutrons (1E-05 eV), and (anti)neutrinos (0, but they are discarded by default anyway)

• Multiple scattering threshold for primary and secondary charged particles lowered to 10 and 20 MeV respectively

• Unrestricted ionisation fluctuations on, for both hadrons/muons and EM particles (if requested) (see option IONFLUCT)

• Both explicit and continuous heavy particle bremsstrahlung and pair production inhibited

EM-CASCAde

• Electromagnetic interactions on (no need for explicit option EMF)

• Rayleigh scattering and inelastic form factor corrections to Compton scattering and Compton profiles activated (no EMFRAY needed)

• Detailed photoelectric edge treatment and fluorescence photons activated (no EMFFLUO needed)

• Restricted ionisation fluctuations for EM particles (see option IONFLUCT)

• Both explicit and continuous heavy particle bremsstrahlung and pair production inhibited

HADROTHErapy

• EMF on

• Inelastic form factor corrections to Compton scattering and Compton profiles activated

• Low-energy neutron transport on down to themral energies included,
  no need for option LOW-NEUT (high energy neutron threshold at 20 MeV)

• Fully analogue absorption for low-energy neutrons

• Particle transport threshold set at 100 keV, except for neutrons (1E-5 eV), and (anti)neutrinos (0, but they are discarded by default anyway)

• Multiple scattering threshold at minimum allowed energy, for both primary and secondary charged particles

• Delta ray production on with threshold 100 keV (see option DELTARAY)

• Restricted ionisation fluctuations on, for both hadrons/muons and EM particles (see option IONFLUCT)

• Tabulation ratio for hadron/muon dp/dx set at 1.03, fraction of the kinetic energy to be lost in a step set at 0.02 (see options DELTARAY, EMFFIX, FLUKAFIX)

ICARUS

• EMF on

• Rayleigh scattering and inelastic form factor corrections to Compton scattering and Compton profiles activated (no EMFRAY needed)

• Detailed photoelectric edge treatment and fluorescence photons activated (no EMFFLUO needed)

• Low energy neutron transport on down to thermal energies included,
  (high energy neutron threshold at 20 MeV)

• Fully analogue absorption for low energy neutrons

• Particle transport threshold set at 100 keV, except neutrons (1E-5 eV), and (anti)neutrinos (0, but they are discarded by default anyway)

• Multiple scattering threshold at minimum allowed energy, for both primary and secondary charged particles

• Delta ray production on with threshold 100 keV (see option DELTARAY)

• Restricted ionisation fluctuations on, for both hadrons/muons and EM particles (see option IONFLUCT)

• Tabulation ratio for hadron/muon dp/dx set at 1.04, fraction of the kinetic energy to be lost in a step set at 0.05, number of dp/dx tabulation points set at 80 (see options DELTARAY, EMFFIX, FLUKAFIX)

• Heavy particle e+/e- pair production activated with full explicit production (with the minimum threshold = 2m_e)

• Heavy particle bremsstrahlung activated with explicit photon production above 300 keV

• Muon photonuclear interactions activated with explicit generation of secondaries

• Heavy fragment transport activated

NEUTRONS

• Low energy neutron transport on down to thermal energies included,
  no need for LOW-NEUT (high energy neutron threshold at 20 MeV)

• Non-analogue absorption for low-energy neutrons with probability 0.95 for the last (thermal) groups

• Both explicit and continuous heavy particle bremsstrahlung and pair production inhibited

NEW-DEFAults (standard defaults active even if the DEFAULT card is not present)

• EMF on, with electron and photon transport thresholds to be set using the EMFCUT command

• Inelastic form factor corrections to Compton scattering activated (no need for EMFRAY)

• Low energy neutron transport on down to thermal energies included,
  (no need for LOW-NEUT). The neutron high energy threshold is set at 20 MeV.

• Non analogue absorption for low energy neutrons with probability 0.95 for the last (thermal) groups

• Particle transport threshold set at 10 MeV, except for neutrons (1E-5 eV), and (anti)neutrinos (0, but they are discarded by default anyway)

• Multiple scattering threshold for secondary charged particles lowered to 20 MeV (equal to that of the primary ones)

• Delta ray production on with threshold 1 MeV (see option DELTARAY)

• Restricted ionisation fluctuations on, for both hadrons/muons and EM particles (see option IONFLUCT)

• Heavy particle e+/e- pair production activated with full explicit production (with the minimum threshold = 2m_e)

• Heavy particle bremsstrahlung activated with explicit photon production above 1 MeV

• Muon photonuclear interactions activated with explicit generation of secondaries

PRECISIOn

• EMF on

• Rayleigh scattering and inelastic form factor corrections to Compton scattering and Compton profiles activated

• Detailed photoelectric edge treatment and fluorescence photons activated

• Low energy neutron transport on down to thermal energies included,
  (high energy neutron threshold at 20 MeV)

• Fully analogue absorption for low-energy neutrons

• Particle transport threshold set at 100 keV, except neutrons (1E-5 eV), and (anti)neutrinos (0, but they are discarded by default anyway)

• Multiple scattering threshold at minimum allowed energy, for both primary and secondary charged particles

• Delta ray production on with threshold 100 keV (see option DELTARAY)

• Restricted ionisation fluctuations on, for both hadrons/muons and EM particles (see option IONFLUCT)

• Tabulation ratio for hadron/muon dp/dx set at 1.04, fraction of the kinetic energy to be lost in a step set at 0.05, number of dp/dx tabulation points set at 80 (see options DELTARAY, EMFFIX, FLUKAFIX)

• Heavy particle e+/e- pair production activated with full explicit production (with the minimum threshold = 2m_e)

• Heavy particle bremsstrahlung activated with explicit photon production above 300 keV

• Muon photonuclear interactions activated with explicit generation of secondaries

• Heavy fragment transport activated

SHIELDINg

• Low energy neutron transport on down the thermal energies included,
  (the neutron high energy threshold is set at 20 MeV)

• Non-analogue absorption for low energy neutrons with probability 0.95 for the last (thermal) groups

• Particle transport threshold set at 10 MeV, except neutrons (1E-5 eV), and (anti)neutrinos (0, but they are discarded by default anyway)

• Multiple scattering threshold for secondary charged particles lowered to 20 MeV (= primary ones)

• Both explicit and continuous heavy particle bremsstrahlung and pair production inhibited

• EMF off!!! This default is meant for simple hadron shielding only!

Notes:

• 1) If an option does not appear in input, FLUKA provides default parameter values in most cases. Standard defaults are also applied when the option is present but not all its WHAT and SDUM parameters have been defined explicitly by the user. However, some types of problems are better handled using different defaults. Option DEFAULTS allows to override the standard ones with others, tuned to a specific class of transport problems. The present set of defaults (valid if no DEFAULTS card is issued) is equivalent to that set by SDUM = NEW-DEFAults.

• 2) IMPORTANT! Option DEFAULTS must be issued at the very beginning of input. It can be preceded only by a GLOBAL card and by command TITLE. This is one of the rare cases, like GLOBAL, MAT-PROP and PLOTGEOM, where sequential order of input cards is of importance in FLUKA (see (7)).

• 3) The name of the SHIELDINg default refers to simple calculations for proton accelerators, where the electromagnetic component can be neglected. It is not applicable to electron accelerator shielding or any other shielding problem where the gamma component is important.

• 4) The responsibility of choosing reasonable defaults, compatible with the rest of input, is left to the user. In particular, choosing the defaults corresponding to pure EM cascade or to pure low-energy neutron problems has the effect of turning off all initialisations related to the hadronic generators. This will save a considerable time at the beginning of the run, but will lead to a crash if a hadron generator is called because of some other input option. In particular, SDUM = EM-CASCA is incompatible with option PHOTONUC and with beam particles different from PHOTON, ELECTRON and POSITRON; and SDUM = NEUTRONS is incompatible with option EMF, with any beam particle different from NEUTRON and with energies higher than 20 MeV. On the other hand, it is possible to override some of the defaults, in particular the various thresholds, by issuing the corresponding command after DEFAULTS (PART-THR, EMFCUT. DELTARAY, etc.)

Example:

 *...+....1....+....2....+....3....+....4....+....5....+....6....+....7....+....8
 DEFAULTS         0.0       0.0       0.0       0.0       0.0      0.0 EM-CASCA
 *  The above declaration refers to a problem where only electrons, positrons
 *  and photons are transported.