DEFAULTS¶

Summary

Sets FLUKA defaults suitable for a specified kind of problems. Starting from FLUKA 99.5 (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 =

CALORIMEtry: defaults for calorimeter simulations

DAMAGE: defaults for for damage/DPA calculations

EET/TRANsmut: defaults for Energy Transformer or transmutation calculations

EM–CASCAde: defaults for pure EM cascades

ICARUS: defaults for studies related to the ICARUS experiment

HADROTHErapy: defaults for hadrotherapy calculations

NEUTRONS: defaults for pure low-energy neutron runs

NEW–DEFAults: reasonable minimal set of new defaults — not needed

PRECISIOn: defaults for precision simulations

SHIELDINg: 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, and annihilation photon acolinearity activated (no EMFRAY needed)
Detailed photoelectric edge treatment and fluorescence photons activated (no EMFFLUO needed)
Low-energy neutron transport on dow to thermal energies included (no LOW–NEUT needed). High energy neutron threshold at 20 MeV.
Fully analogue absorption for low-energy neutrons
Built-in low energy neutron pointwise cross sections activated for \(^1\)H, \(^2\)H, \(^3\)He, \(^4\)He, \(^6\)Li, \(^{12}\)C, down to 10\(^{-5}\) eV, except for bound \(^1\)H, \(^2\)H, \(^{12}\)C in graphite (down to 3 eV).
Heavy evaporation activated up to mass 9, charge 4, included (see option PHYSICS)
Particle transport threshold set at \(1 \times {m}_{part} / {m}_{prot}\) MeV, except for neutrons (\(1 \times 10^{-5}\) 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)
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\(_{e}\))
Heavy particle bremsstrahlung activated with explicit photon production above 300 keV
Muon photonuclear interactions activated with explicit generation of secondaries
Detailed heavy fragment transport activated

DAMAGE

EMF on (no need for an EMF card)
Rayleigh scattering and inelastic form factor corrections to Compton scattering and Compton profiles, and annihilation photon acolinearity activated (no EMFRAY needed)
Detailed photoelectric edge treatment and fluorescence photons activated (no EMFFLUO needed)
Low-energy neutron transport on dow to thermal energies included (no LOW–NEUT needed). High energy neutron threshold at 20 MeV. Pointwise treatment where available.
Non-analogue absorption for low-energy neutrons with probability 0.98 for the last (thermal) groups
Built-in low energy neutron pointwise cross sections activated for \(^1\)H, \(^2\)H, \(^3\)He, \(^4\)He, \(^6\)Li, \(^{12}\)C, down to 10\(^{-5}\) eV, except for bound \(^1\)H, \(^2\)H, \(^{12}\)C in graphite (down to 3 eV).
Heavy evaporation activated up to mass 9, charge 4, included (see option PHYSICS)
Particle transport threshold set at 1 keV/n, except neutrons (\(1 \times 10^{-5}\)eV), e\(^\pm\) (m\(_e\)/2), photons (m\(_e\)/4), 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 0.04 (see options DELTARAY, EMFFIX, FLUKAFIX)
Heavy particle \(e^+\)\(e^-\) pair production activated with full explicit production (with the minimum threshold = 2 m\(_{e}\))
Heavy particle bremsstrahlung activated with explicit photon production above 300 keV
Muon photonuclear interactions activated with explicit generation of secondaries
Detailed heavy fragment transport activated

EET/TRANsmut

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 (\(1 \times 10^{-5}\)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, and annihilation photon acolinearity 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, and annihilation photon acolinearity activated
Detailed photoelectric edge treatment and fluorescence photons activated (no EMFFLUO needed)
Low-energy neutron transport on down to thermal energies included, no need for option LOW–NEUT (high energy neutron threshold at 20 MeV)
Fully analogue absorption for low-energy neutrons
Built-in low energy neutron pointwise cross sections activated for \(^1\)H, \(^2\)H, \(^3\)He, \(^4\)He, \(^6\)Li, \(^{12}\)C, down to 10\(^{-5}\) eV, except for bound \(^1\)H, \(^2\)H, \(^{12}\)C in graphite (down to 3 eV).
Particle transport threshold set at 300 keV, except for photons (100 keV), neutrons (\(1 \times 10^{-5}\) 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 300 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)
Detailed heavy fragment transport activated
Transport and decay in flight of ions in excited states
Both explicit and continuous heavy particle bremsstrahlung and pair production inhibited
No photo-nuclear, electro-nuclear or muon-nuclear interactions (see PHOTONUC and MUPHOTON)

ICARUS

EMF on
Rayleigh scattering and inelastic form factor corrections to Compton scattering and Compton profiles, and annihilation photon acolinearity 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
Built-in low energy neutron pointwise cross sections activated for \(^1\)H, \(^2\)H, \(^3\)He, \(^4\)He, \(^6\)Li, \(^{12}\)C, down to 10\(^{-5}\) eV, except for bound \(^1\)H, \(^2\)H, \(^{12}\)C in graphite (down to 3 eV).
Heavy evaporation activated up to mass 9, charge 4, included (see option PHYSICS)
Particle transport threshold set at 100 keV, except neutrons (\(1 \times 10^{-5}\) 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 = 2 m\(_{e}\))
Heavy particle bremsstrahlung activated with explicit photon production above 300 keV
Muon photonuclear interactions activated with explicit generation of secondaries
Detailed 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
Built-in low energy neutron pointwise cross sections activated for \(^1\)H, \(^2\)H, \(^3\)He, \(^4\)He, \(^6\)Li, \(^{12}\)C, down to 10\(^{-5}\) eV, except for bound \(^1\)H, \(^2\)H, \(^{12}\)C in graphite (down to 3 eV).
Both explicit and continuous heavy particle bremsstrahlung and pair production inhibited

NEW–DEFAults ( standard defaults active even if the DEFAULTS card is not present)

EMF on, with electron and photon transport thresholds to be set using 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 (\(1 \times 10^{-5}\) 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 = 2 m\(_{e}\))
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, and annihilation photon acolinearity 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
Built-in low energy neutron pointwise cross sections activated for \(^1\)H, \(^2\)H, \(^3\)He, \(^4\)He, \(^6\)Li, \(^{12}\)C, down to 10\(^{-5}\) eV, except for bound \(^1\)H, \(^2\)H, \(^{12}\)C in graphite (down to 3 eV).
Heavy evaporation activated up to mass 9, charge 4, included (see option PHYSICS)
Particle transport threshold set at 100 keV, except neutrons (\(1 \times 10^{-5}\) 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 = 2 m\(_{e}\))
Heavy particle bremsstrahlung activated with explicit photon production above 300 keV
Muon photonuclear interactions activated with explicit generation of secondaries
Transport and decay in flight of ions in excited states
Detailed heavy fragment transport activated

SHIELDINg

Low-energy neutron transport on down to 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) group
Particle transport threshold set at 10 MeV, except neutrons (\(1 \times 10^{-5}\) 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

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.
Important! Option DEFAULTS must be issued at the very beginning of input. It can be preceded only by a GLOBAL card and by 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 General features of FLUKA input).
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.
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/source 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....+....
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.

Defaults defined by different `SDUM` values of the `DEFAULTS` command¶
			`SDUM` values
Command		`DEFAULTS card missing`	`CALORIME`	`EET/TRAN`	`EM–CASCA`	`HADROTHE`	`ICARUS`	`NEUTRONS`	`NEW–DEFA`	`PRECISIO`	`SHIELDIN`
`DELTARAY`	`WHAT(1)`	`0.001`	`0.0001`	`-1.`	`-1.`	`0.0001`	`0.0001`	`-1.`	0.001	`0.0001`	`-1.`
	`WHAT(2)`	`50.`	`80.`	`50.`	`50.`	`50.`	`80.`	`50.`	50.	`80.`	`50.`
	`WHAT(3)`	`1.15`	`1.15`	`1.15`	`1.15`	`1.03`	`1.04`	`1.15`	1.15	`1.04`	`1.15`
`EMF`		ON	ON	OFF	ON	ON	ON	OFF	ON	ON	OFF
`EMFFLUO`	`WHAT(1)`	`0.`	`1.`	`0.`	`1.`	`0.`	`1.`	`0.`	0.	`1.`	`0.`
`EMFRAY`	`WHAT(1)`	`3.`	`1.`	`0.`	`1.`	`3.`	`1.`	`0.`	3.	`1.`	`0.`
`EVENTYPE`	`WHAT(3)`	`1.`	`1.`	`1.`	`-2.`	`1.`	`1.`	`-2.`	1.	`1.`	`1.`
`FLUKAFIX`	`WHAT(1)`	`0.1`	`0.08`	`0.1`	`0.1`	`0.05`	`0.02`	`0.1`	0.1	`0.05`	`0.1`
`IONFLUCT`	`WHAT(1)`	`1.`	`1.`	`1.`	`-1.`	`1.`	`1.`	`-1.`	1.	`1.`	`-1.`
	`WHAT(2)`	`1.`	`1.`	`-1.`	`1.`	`1.`	`1.`	`-1.`	1.	`1.`	`-1.`
`LOW–BIAS`	`WHAT(1)`	`0.`	`0.`	`0.`	N.A.	`0.`	`0.`	`0.`	0.	`0.`	`0.`
	`WHAT(2)`	`230.`	`261.`	`230.`	N.A.	`230.`	`261.`	`261.`	230.	`261.`	`230.`
	`WHAT(3)`	`0.85`	N.A.	`0.95`	N.A.	`0.95`	N.A.	N.A.	0.95	N.A.	`0.95`
`LOW–NEUT`		ON	ON	ON	OFF	ON	ON	ON	ON	ON	ON
	`WHAT(6)`	`0.`	`1.`	`0.`	`0.`	`0.`	`1.`	`1.`	0.	`1.`	`0.`
`MCSTHRES`	`WHAT(1)`	`-0.02`	`1.`	`-0.01`	`-0.02`	`1.`	`1.`	`-0.02`	-0.02	`1.`	`-0.02`
	`WHAT(2)`	`-0.02`	`1.`	`-0.02`	`-1.`	`1.`	`1.`	`-1.`	-0.02	`1.`	`-0.02`
`PAIRBREM`	`WHAT(1)`	`3.`	`3.`	`-3.`	`-3.`	`3.`	`3.`	`-3.`	3.	`3.`	`-3.`
	`WHAT(2)`	`0.`	`0.`	N.A.	N.A.	`-1.`	`0.`	N.A.	0.	`0.`	N.A.
	`WHAT(3)`	`0.001`	`0.0003`	N.A.	N.A.	`-1.`	`0.0003`	N.A.	0.001	`0.0003`	N.A.
`PART–THR`	`WHAT(1)`	`-0.010`	\(-0.001 \frac{ m}{ m_{ p}}\)	`-0.001`	N.A.	`-0.0001`	`-0.0001`	N.A.	-0.010	`-0.0001`	`-0.010`