MAT–PROP¶
Summary
Provides extra information about materials
MATERIAL, STERNHEImeto supply extra information about gaseous materials and materials with fictitious or effective density
to override the default average ionisation potential
to set a flag to call the user routine
USRMEDevery time a particle is going to be transported in selected material(s)to set the energy threshold for DPAs (Displacements Per Atom)
to set the athermal recombination (arc) parameters for arc DPA scoring
to choose the partition function for non-ionising energy losses (NIEL) and DPA scoring
to choose the screening radius for NIEL and DPA scoring
to set the temperature of pointwise neutron cross sections
to activate or deactivate neutron reflectivity between specific materials
to activate or deactivate X-ray reflectivity between specific materials
For SDUM other than DPA-ENER, NIEL-PFN, PWXSTEMP, N-REFLECtivity, USERDIREctive or X-REFLECtivity¶
- WHAT(1) > 0.0:
gas pressure in atmospheres (see Note 1 below).
- = 0.0:
ignored
- < 0.0:
resets to 1 atm a possible previously input pressure value
- Default
= 1.0
- WHAT(2) =
RHOR factor: this factor multiplies the density of a material when calculating the density effect parameters (e.g. if a reduced density is used to simulate voids, but of course the density effect parameters must be computed with the actual local physical density at the microscopic level). See Note 3 below.- = 0.0:
ignored
- < 0.0:
a possible previously input value is restored to default
= 1.0- Default
= 1.0
- WHAT(3) > 0.0:
average ionisation potential to be used for dE/dx calculations (eV)
- < 0.0:
a default value of the average ionisation potential is obtained from the systematics of Ziegler [Zie77] or Sternheimer, Berger and Seltzer [Ste82, Ste84]
- = 0.0:
ignored
- Default
: ionisation potential calculated from systematics
- WHAT(4) =
- lower bound of the indices of materials, or corresponding name, in which gas pressure,
RHORfactor or ionisation potential are set(“From material ``WHAT(4)``…”) - Default
= 3.0
- WHAT(5) =
- upper bound of the indices of materials, or corresponding name, in which gas pressure,
RHORfactor or ionisation potential are set(“…to material ``WHAT(5)``…”) - Default
=
WHAT(4)- WHAT(6) =
- step length in assigning indices(“…in steps of ``WHAT(6)`` ”)
- Default
= 1.0
- Default
: (option
MAT–PROPnot given): if the density of the default material or that assigned by aMATERIALcard is> 0.01, the material is not assumed to be a gas. Otherwise it is a gas at a default pressure of 1 atmosphere. If the material is a compound, the average ionisation potential is that resulting from applying Bragg’s rule of additivity to stopping power.
For SDUM = DPA–ENER:
- WHAT(1) > 0.0:
Damage energy threshold (eV) for the given materials. (see Note 5)
- = 0.0:
ignored
- < 0.0:
resets to default
- Default
: values from the literature for elements; 30 eV for compounds
- WHAT(2)
- > 0.0: |b| coefficient for athermal recombination (arc)= 0.0: ignored< 0.0: resets to defaultDefault = b, c from literature if available, arc Xsi, if no data available or compound the Smirnov Xsi parameterization is used
- WHAT(3)
- > 0.0: c coefficient for athermal recombination (arc)= 0.0: ignored< 0.0: resets to default (b, c from literature if available, arc Xsi, if no data available or compound the Smirnov Xsi parameterization is used)
- WHAT(4) =
- lower bound of the indices of materials, or corresponding name, in which the damage energy threshold and possible arc parameters have to be applied(“From material ``WHAT(4)``…”)
- Default
= 3.0
- WHAT(5) =
- upper bound of the indices of materials, or corresponding name, in which the damage energy threshold and possible arc parameters have to be applied(“…to material ``WHAT(5)``…”)
- Default
=
WHAT(4)- WHAT(6) =
- step length in assigning indices(“…in steps of ``WHAT(6)`` ”)
- Default
= 1.0
- Default
(option
MAT–PROPnot given): Damage energy thresholds from the literature for elements and 30 eV for compounds
For SDUM = N-REFLECtivity¶
- WHAT(1)
- = flag activating/deactivating reflectivity for neutrons when entering the material(s) defined by what(4-6). 0.0 : ignored> 0.0 : neutron reflectivity activated. 1000 means a call to the user routine usnrfl will be performed at run time every time the neutron is going to cross the surface between the selected materials. At present this is the only option implemented.< 0.0 : resets to default (no neutron reflectivity)Default = no call (-1.0)
- WHAT(2)
= neutron incoming material when reflectivity must be applied Default = 2 (vacuum).
- WHAT(3)
= Not used
- WHAT(4)
= lower bound of the indices of materials, or corresponding name, for which the neutron reflectivity has to be computed (“From material WHAT(4)…”) Default = 3.0
- WHAT(5)
= upper bound of the indices of materials, or corresponding name, for which the neutron reflectivity has to be computed (”… to material WHAT(5)…”) Default = WHAT(4)
- WHAT(6)
= step length in assigning indices (”…in steps of WHAT(6)”) Default = 1.
Default (option MAT-PROP not given): no neutron reflectivity
For SDUM = NIEL-PFN:¶
- WHAT(1)
- = Flag for the Lindhard partition function approximation to be used for NIEL/DPA calculations:= 0.0: ignored= 1.0: Jun/Robinson approximation w/o empirical correction= 2.0: Jun/Robinson approximation with empirical correction= 3.0: Akkerman approximation< 0.0: resets to defaultDefault = 3.0
- WHAT(2)
- = Flag for the screening potential radius model used for the Lindhard partition function:= 0.0: ignored= 1.0: Moliere screening radius= 2.0: Ziegler, Biersack, and Littmark screening radius< 0.0: resets to defaultDefault = 1.0
- WHAT(3)
= not used
- WHAT(4)
= lower bound of the indices of materials, or corresponding name, in which the chosen partition function and screening radius parameters parameters have to be applied (“From material WHAT(4)…”) Default = 3.0
- WHAT(5)
= upper bound of the indices of materials, or corresponding name, in which the chosen partition function and screening radius parameters parameters have to be applied (”… to material WHAT(5)…”) Default = WHAT(4)
- WHAT(6)
= step length in assigning indices (”…in steps of WHAT(6)”) Default = 1.
Default (option MAT-PROP not given): Jun/Robinson partition function approximation with empirical correction factor and Moliere screening radius used for all materials
For SDUM = PWXSTEMP:¶
- WHAT(1)
- = Temperature for pointwise neutron cross sections for the given FLUKA material:= 0.0: ignored> 0.0: pointwise cross section temperature (K)< 0.0: resets to defaultDefault = the temperature of the corresponding group cross section dataset
- WHAT(2)
= not used
- WHAT(3)
= not used
- WHAT(4)
= lower bound of the indices of materials, or corresponding name, to which the pointwise cross section temperature has to be applied (“From material WHAT(4)…”) Default = 3.0
- WHAT(5)
= upper bound of the indices of materials, or corresponding name, to which the pointwise cross section temperature has to be applied (”… to material WHAT(5)…”) Default = WHAT(4)
- WHAT(6)
= step length in assigning indices (”…in steps of WHAT(6)”) Default = 1.
Default (option MAT-PROP not given): the temperature of the corresponding group cross section dataset, or the the one specified in the LOW-PWXS option is applied to all pointwise neutron cross sections
For SDUM = USERDIREctive:
- WHAT(1) = 0.0:
ignored
- > 0.0:
a call to the user routine
USRMEDwill be performed at run time every time a particle is going to be transported in the selected materials (spot depositions are anyway performed: i.e., they cannot be killed byUSRMED)- < 0.0:
a possible previously given value is restored to default (i.e. no call to
USRMEDis made)- WHAT(2)
and WHAT(3): not used
- WHAT(4) =
- lower bound of the indices of materials, or corresponding name, in which the call to
USRMEDmust be performed(“From material ``WHAT(4)``…”) - Default
= 3.0
- WHAT(5) =
- upper bound of the indices of materials, or corresponding name, in which the call to
USRMEDmust be performed(“…to material ``WHAT(5)``…”) - Default
=
WHAT(4)- WHAT(6) =
- step length in assigning indices(“…in steps of ``WHAT(6)`` ”)
- Default
= 1.0
- Default
(option
MAT–PROPnot given): no extra information about the assigned materials is supplied
For SDUM = X-REFLECtivity:
- WHAT(1) = 0.0:
ignored
- > 0.0:
X-ray reflectivity activated, using the
WHAT(1)\(^{th}\) form factor data set. 1000 means a call to the user routineUSXRFLwill be performed at run time every time the X-ray is going to cross tha surface bewteen the selected materials. At present only material data set 998 is available (form factors used in the X-ray complex refraction coefficients taken from EPICS), soWHAT(1)should be 998 or 1000- < 0.0:
a possible previously given value is restored to default (i.e. no X-ray reflectivity)
- WHAT(2) =
X-ray incoming material when reflectivity must be applied
- Default
= 2.0 (vacuum)
- WHAT(3) :
not used
- WHAT(4) =
- lower bound of the indices of materials, or corresponding name, for which the X-ray reflectivity has to be computed(“From material ``WHAT(4)``…”)
- Default
= 3.0
- WHAT(5) =
- upper bound of the indices of materials, or corresponding name, for which the X-ray reflectivity has to be computed(“…to material ``WHAT(5)``…”)
- Default
=
WHAT(4)- WHAT(6) =
- step length in assigning indices(“…in steps of ``WHAT(6)`` ”)
- Default
= 1.0
- Default
(option
MAT–PROPnot given): no X-ray reflectivity
SDUM = blank (i.e. ≠ DPA–ENER, USERDIREctive, X-REFLECtivity):
- When issuing a
MATERIALdefinition the gas pressure is set to 1 atm if the densityRHOis< 0.01. If this value is not acceptable to the user, aMAT–PROPcard must be issued after theMATERIALcard to force a different value of the gas pressure. Note that this is one of the rare cases (withGLOBAL, DEFAULTSandPLOTGEOM) where sequential order of input cards is of importance in FLUKA. If
WHAT(1)is set to a value> 0.0, the transport of charged particles will be calculated according to a densityRHOdefined at the actual pressure by the correspondingMATERIALcard, while the density effect correction to stopping power will be calculated using a density \(\rho({NTP})\) =RHO/WHAT(1) and then re-scaled to the actual densityRHO.- When giving a
WHAT(2)non-zero value, remember that ifRHO(defined by a MATERIAL card) indicates the “transport (effective) density”, the “physical density” used to calculate the density effect on stopping power will beRHOR*RHO = WHAT(2)*RHO.ForSDUM = DPA–ENER: Displacement damage can be induced by all particles produced in a cascade, including high energy photons. The latter, however, have to initiate a reaction producing charged particles, neutrons or ions.
- The damage threshold is the minimum energy needed to produce a defect. Typical values used in the Njoy99 code [NJOY] are:Li: 10 eV, C in SiC: 20 eV, Graphite: 30\(\cdots\) 35 eV, Al: 27 eV, Si: 25 eV, Mn, Fe, Co, Ni, Cu, Nb: 40 eV, Mo: 60 eV, W: 90 eV, Pb: 25 eV FLUKA provides literature-based defaults for all elements in the absence of explicit input.
The default damage threshold for compounds is 30 eV. There is no general physical algorithm to derive it from the constituents; for example, an alloy can have a different crystalline structure. The user must set a meaningful threshold for the compound.
- In most problems, the expected DPA values are generally expressed by very small numbers.
SDUM = USERDIREctive: For
SDUM = N-REFLECtivity, only one incoming material is permitted. To apply reflectivity from several incoming materials, define the reflecting material more than once with different names and issue the correspondingMAT-PROPcards. The user routineUSNRFLis always invoked; the user must return the reflection coefficient.- User routine
USRMEDis typically used to implement albedo and refraction, especially in connection with optical photon transport as defined byOPT–PROP. See USRMED: USeR MEDium dependent directives for instructions.SDUM = X-REFLECtivity: Only one incoming material is permitted. If reflectivity on a given material is requested incoming from more than one material, please define the material twice with different names and issue twice the relevant
MAT–PROPcards.The reflection coefficients are in general different for X-rays polarized parallel or perpendicular to the incidence plane. Therefore, even an unpolarized incident beam can become partially polarized after being reflected.
When the user routine
USXRFLis invoked, the user is responsible for returning the reflection coefficients for parallel and perpendicular incident polarization.The complex refraction coefficients are based on the EPICS anomalous real (\(f_1\)) and imaginary (\(f_2\)) form factors, which become meaningless below about 100 eV. At vacuum–material interfaces, photons below the 100 eV transport threshold (for example from synchrotron radiation) can impinge: X-ray reflectivity is calculated down to 30 eV, although this can be questionable. Below a few tens of eV, photons can be treated as optical photons by supplying the required optical properties.
Example 1 (number based):
* Call USRMED every time a particle is going to be transported in Pb Glass or
* in plexiglas (PMMA)
*...+....1....+....2....+....3....+....4....+....5....+....6....+....7....+...
MATERIAL 1. 0.0 8.3748E-5 3. 0.0 1. HYDROGEN
MATERIAL 6. 0.0 2.265 6. 0.0 0. CARBON
MATERIAL 8. 0.0 0.001429 8. 0.0 0. OXYGEN
MATERIAL 14. 0.0 2.33 14. 0.0 0. SILICON
MATERIAL 22. 0.0 4.54 11. 0.0 0. TITANIUM
MATERIAL 33. 0.0 5.73 12. 0.0 0. ARSENIC
MATERIAL 82. 0.0 11.35 17. 0.0 0. LEAD
MATERIAL 0. 0. 6.22 18. 0.0 0. LEADGLAS
COMPOUND -0.156453 8. -0.080866 14. -0.008092 11. LEADGLAS
COMPOUND -0.002651 12. -0.751938 17. 0.0 0. LEADGLAS
MATERIAL 0. 0. 1.19 15. 0.0 0. PMMA
COMPOUND -0.080538 3. -0.599848 6. -0.319614 8. PMMA
MAT-PROP 1.0 0.0 0.0 15. 18. 3. USERDIRE
The same example, name based:
*...+....1....+....2....+....3....+....4....+....5....+....6....+....7....+...
MATERIAL 1. 0.0 8.3748E-5 0.0 0.0 1. HYDROGEN
MATERIAL 6. 0.0 2.265 0.0 0.0 0. CARBON
MATERIAL 8. 0.0 0.001429 0.0 0.0 0. OXYGEN
MATERIAL 14. 0.0 2.33 0.0 0.0 0. SILICON
MATERIAL 22. 0.0 4.54 0.0 0.0 0. TITANIUM
MATERIAL 33. 0.0 5.73 0.0 0.0 0. ARSENIC
MATERIAL 82. 0.0 11.35 0.0 0.0 0. LEAD
MATERIAL 0. 0. 6.22 0.0 0.0 0. LEADGLAS
COMPOUND -0.156453 OXYGEN -0.080866 SILICON -0.008092 TITANIUM LEADGLAS
COMPOUND -0.002651 ARSENIC -0.751938 LEAD 0.0 0. LEADGLAS
MATERIAL 0. 0. 1.19 0.0 0.0 0. PMMA
COMPOUND -0.080538 HYDROGEN -0.599848 CARBON -0.319614 OXYGEN PMMA
MAT-PROP 1.0 0.0 0.0 PMMA LEADGLAS 3. USERDIRE
Example 2:
* Lung tissue with ICRP composition and Sternheimer parameters
*...+....1....+....2....+....3....+....4....+....5....+....6....+....7....+...
MATERIAL 1. 0.0 8.3748E-5 3. 0.0 1. HYDROGEN
MATERIAL 6. 0.0 2.265 6. 0.0 0. CARBON
MATERIAL 7. 0.0 0.0011653 7. 0.0 0. NITROGEN
MATERIAL 8. 0.0 0.001429 8. 0.0 0. OXYGEN
MATERIAL 12. 0.0 1.74 9. 0.0 0. MAGNESIU
MATERIAL 11. 0.0 0.971 10. 0.0 0. SODIUM
MATERIAL 26. 0.0 7.874 11. 0.0 0. IRON
MATERIAL 16. 0.0 2.0 12. 0.0 0. SULFUR
MATERIAL 17. 0.0 2.9947E-3 13 0.0 0. CHLORINE
MATERIAL 19. 0.0 0.862 14. 0.0 0. POTASSIU
MATERIAL 15. 0.0 2.2 16. 0.0 0. PHOSPHO
MATERIAL 30. 0.0 7.133 17. 0.0 0. ZINC
MATERIAL 20. 0.0 1.55 21. 0.0 0. CALCIUM
* Average density of lung is 0.3 g/cm3
MATERIAL 0.0 0.0 0.3 18. 0.0 0. LUNG
COMPOUND -0.101278 3. -0.10231 6. -0.02865 7. LUNG
COMPOUND -0.757072 8. -0.00184 10. -0.00073 9. LUNG
COMPOUND -0.0008 16. -0.00225 12. -0.00266 13. LUNG
COMPOUND -0.00194 14. -0.00009 21. -0.00037 11. LUNG
COMPOUND -0.00001 17. 0. 0. 0. 0. LUNG
* Local density of lung is 1.05 = 0.3*3.50 g/cm3. Average ionisation
* potential is 75.3 eV (At. Data Nucl. Data Tab. 30, 261 (1984))
MAT-PROP 0.0 3.50 75.3 18. 0. 0.
STERNHEI 3.4708 0.2261 2.8001 0.08588 3.5353 0. 18
The same example, name based:
*...+....1....+....2....+....3....+....4....+....5....+....6....+....7....+...
MATERIAL 1. 0.0 8.3748E-5 0.0 0.0 1. HYDROGEN
MATERIAL 6. 0.0 2.265 0.0 0.0 0. CARBON
MATERIAL 7. 0.0 0.0011653 0.0 0.0 0. NITROGEN
MATERIAL 8. 0.0 0.001429 0.0 0.0 0. OXYGEN
MATERIAL 12. 0.0 1.74 0.0 0.0 0. MAGNESIU
MATERIAL 11. 0.0 0.971 0.0 0.0 0. SODIUM
MATERIAL 26. 0.0 7.874 0.0 0.0 0. IRON
MATERIAL 16. 0.0 2.0 0.0 0.0 0. SULFUR
MATERIAL 17. 0.0 2.9947E-3 0.0 0.0 0. CHLORINE
MATERIAL 19. 0.0 0.862 0.0 0.0 0. POTASSIU
MATERIAL 15. 0.0 2.2 0.0 0.0 0. PHOSPHO
MATERIAL 30. 0.0 7.133 0.0 0.0 0. ZINC
MATERIAL 20. 0.0 1.55 0.0 0.0 0. CALCIUM
MATERIAL 0.0 0.0 0.3 0.0 0.0 0. LUNG
COMPOUND -0.101278 HYDROGEN -0.10231 CARBON -0.02865 NITROGEN LUNG
COMPOUND -0.757072 OXYGEN -0.00184 SODIUM -0.00073 MAGNESIU LUNG
COMPOUND -0.0008 PHOSPHO -0.00225 SULFUR -0.00266 CHLORINE LUNG
COMPOUND -0.00194 POTASSIU -0.00009 CALCIUM -0.00037 IRON LUNG
COMPOUND -0.00001 ZINC 0. 0. 0. 0. LUNG
MAT-PROP 0.0 3.50 75.3 LUNG 0. 0.
STERNHEI 3.4708 0.2261 2.8001 0.08588 3.5353 0. LUNG
Example 3 (number based):
* Definition of air at non-standard pressure.
*...+....1....+....2....+....3....+....4....+....5....+....6....+....7....+...
MATERIAL 6. 0.0 2.265 6. 0.0 0. CARBON
MATERIAL 7. 0.0 0.0011653 7. 0.0 0. NITROGEN
MATERIAL 8. 0.0 0.001429 8. 0.0 0. OXYGEN
MATERIAL 18. 0.0 1.662E-3 20. 0.0 0. ARGON
* AIR defined as air with normal NTP density (0.001205)
MATERIAL 0.0 0.0 0.001205 10. 0.0 0. AIR
COMPOUND -0.000124 6. -0.755267 7. -0.231781 8. AIR
COMPOUND -0.012827 20. AIR
* AIR2 defined as air with a density 0.002410, double of that at NTP
MATERIAL 0.0 0.0 0.002410 11. 0.0 0. AIR2
COMPOUND -0.000124 6. -0.755267 7. -0.231781 8. AIR2
COMPOUND -0.012827 20. AIR2
* The pressure of AIR2 is 2 atm. Set also the ionisation potential = 85.7 eV
MAT-PROP 2.0 0.0 85.7 11.
STERNHEI 10.5961 1.7418 4.2759 0.10914 3.3994 0. 11
The same example, name based:
*...+....1....+....2....+....3....+....4....+....5....+....6....+....7....+...
MATERIAL 6. 0.0 2.265 0.0 0.0 0. CARBON
MATERIAL 7. 0.0 0.0011653 0.0 0.0 0. NITROGEN
MATERIAL 8. 0.0 0.001429 0.0 0.0 0. OXYGEN
MATERIAL 18. 0.0 1.662E-3 0.0 0.0 0. ARGON
MATERIAL 0.0 0.0 0.001205 0.0 0.0 0. AIR
COMPOUND -0.000124 CARBON -0.755267 NITROGEN -0.231781 OXYGEN AIR
COMPOUND -0.012827 ARGON AIR
MATERIAL 0.0 0.0 0.002410 0.0 0.0 0. AIR2
COMPOUND -0.000124 CARBON -0.755267 NITROGEN -0.231781 OXYGEN AIR2
COMPOUND -0.012827 ARGON AIR2
MAT-PROP 2.0 0.0 85.7 AIR2
STERNHEI 10.5961 1.7418 4.2759 0.10914 3.3994 0. AIR2
%* The total and capture cross sections of Au have a good 1/v dependence in the
%* thermal region. Here we assume Gold to be at a temperature of 300K, while
%* the cross sections in the 72-group ENEA library are at 293K.
%*...+....1....+....2....+....3....+....4....+....5....+....6....+....7....+...
%LOW-NEUT 72.0 22.0 0.0196 0. 1.0 0.
%MATERIAL 79.0 0.0 19.32 15. 0.0 0.
%* (300/293 = 1.02389). The ENEA library has only 1 thermal group.
%MAT-PROP 1.02389 1.0 293. 15. 0.0 0. LOWNTEMP
%
%*...+....1....+....2....+....3....+....4....+....5....+....6....+....7....+...
%LOW-NEUT 72.0 22.0 0.0196 0. 1.0 0.
%MATERIAL 79.0 0.0 19.32 0.0 0.0 0. GOLD
%MAT-PROP 1.02389 1.0 293. GOLD 0.0 0. LOWNTEMP
%