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MAT-PROP


    Provides extra information about materials

    See also MATERIAL, STERNHEIme

    This command can be used for several different tasks:

    1) to supply extra information about gaseous materials and
       materials with fictitious or effective density.
    2) to override the default average ionisation potential.
    3) to set a flag to call the user routine USRMED every time a particle is
       going to be transported in the selected material(s)
    4) to set the energy threshold for DPAs (Displacements Per Atom)
* Start_Devel_seq
    5) to do a rough rescaling of thermal neutron cross sections
       if the actual material temperature is different from the one of
       the low energy neutron cross section data set.

    For 
SDUM
whatever except DPA-ENER, LOWNTEMP, USERDIREctive: * End_Devel_seq * Start_Prod_seq For
SDUM
whatever except DPA-ENER, USERDIREctive: * End_Prod_seq
WHAT(1)
= Gas pressure in atmospheres. 0.0 : ignored < 0.0 : resets to 1 atm a possible previously input pressure value
WHAT(2)
= RHOR factor : this factor multiplies the density of the material(s) 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: average ionisation potential to be used for dE/dx calculations (eV) < 0: a default value of the average ionisation potential is obtained from the systematics of Ziegler [Zie77] or Sternheimer, Berger and Seltzer [Ste84] = 0: ignored
Default
: ionisation potential calculated from systematics
WHAT(4)
= lower bound of the indices of materials, or corresponding name, in which gas pressure, RHOR factor 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, RHOR factor 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.
Default
(option MAT-PROP not given): if the density of the default material or that assigned by a MATERIAL card 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
Default
= 30 eV
WHAT(2)
= Not used
WHAT(3)
= Not used
WHAT(4)
= lower bound of the indices of materials, or corresponding name, in which the damage energy threshold has 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 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): Damage energy threshold = 30 eV for all materials * Start_Devel_seq For
SDUM
= LOWNTEMP:
WHAT(1)
= Temperature ratio (T_actual/T_xsec) with respect to the nominal one. The nominal temperature T_xsec (given by
WHAT(3)
, see below) is the temperature for which the neutron cross sections of the FLUKA material(s) concerned have been prepared (see the Table in 10}). See Notes d.1), d.2), d.3) for more details and limitations. = 0.0 : ignored < 0.0 : a possible previously given value is restored to default = 1.0
Default
= 1.0
WHAT(2)
= Number of (thermal) groups to which the temperature ratio has to be applied. It must be <= N_th, where N_th is the number of thermal groups in the cross section library. If
WHAT(2)
< N_th, the last
WHAT(2)
groups are affected (see the LOW-NEUT option for setting the number of thermal groups). = 0.0 : ignored < 0.0 : a possible previously given value is restored to default = 0.0
Default
= 0.0 (i.e., no correction, the whole command is ignored).
WHAT(3)
= Nominal temperature (K) of the indicated FLUKA materials = 0.0 : ignored < 0.0 : a possible previously given value is restored to default (3rd identifier, see below)
Default
= the temperature given as 3rd identifier of the associated low energy neutron data set (see LOW-MAT and the cross section description in 10})
WHAT(4)
= lower bound of the indices of materials, or corresponding name, in which the temperature rescaling has 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 temperature rescaling 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): No cross section re-scaling * End_Devel_seq For
SDUM
= USERDIREctive
WHAT(1)
= 0.0 : ignored > 0.0 : a call to the user routine USRMED (see 13.2.28}) will 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 by USRMED) < 0.0 : a possible previously given value is restored to default = no call
Default
= no call (-1.0)
WHAT(2)
= Not used
WHAT(3)
= Not used
WHAT(4)
= lower bound of the indices of materials for which the call to USRMED has to be performed ("From material
WHAT(4)
...")
Default
= 3.0
WHAT(5)
= upper bound of the indices of materials for which the call to USRMED has to be performed ("... 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 extra information about the assigned materials is supplied.
Notes:
* Start_Devel_seq
SDUM
= blank (i.e. /= DPA-ENER, LOWNTEMP, USERDIREctive): * End_Devel_seq * Start_Prod_seq
SDUM
= blank (i.e. /= DPA-ENER, USERDIREctive): * End_Prod_seq 1) When issuing a MATERIAL definition the gas pressure is set to 1 if the density RHO is < 0.01. If this value is not acceptable to the user, a MAT-PROP card must be issued AFTER the MATERIAL card to force a different value of the gas pressure. Note that this is one of the rare cases (with GLOBAL, DEFAULTS and PLOTGEOM) where sequential order of input cards is of importance in FLUKA. A non-zero value of
WHAT(1)
must be given only for gases: it is important when calculating the density effect parameters of the stopping power (see Note 1 to option STERNHEIme and Note 2 here below). 2) If
WHAT(1)
is set to a value > 0.0, the transport of charged particles will be calculated according to a density RHO defined at the actual pressure by the corresponding MATERIAL card, 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 density RHO. 3) When giving a
WHAT(2)
non-zero value, remember that if RHO (defined by a MATERIAL card) indicates the "transport (effective) density", the "physical density" used to calculate the density effect on stopping power will be RHOR*RHO =
WHAT(2)
*RHO
SDUM
= DPA-ENER: 4) 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. 5) 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...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 6) In most problems, the expected DPA values are generally expressed by very small numbers.
SDUM
= USERDIREctive: 7) User routine USRMED is typically used to implement albedo and refraction, especially in connection with optical photon transport as defined by OPT-PROP. See 13} for instructions. * Start_Devel_seq
SDUM
= LOWNTEMP: d.1) At present, temperature rescaling can be done only for the 72-group neutron cross section library. d.2) The temperature ratio is used to rescale the thermal group velocities, absorption probabilities, gamma generation probabilities, fission probabilities and kermas. For absorption, fission and gamma generation a 1/v dependence of the corresponding cross sections is implicitly assumed: IF THIS IS NOT THE CASE THE WHOLE PROCEDURE IS MEANINGLESS. No modification is made to the elastic cross section and hence to the downscattering matrix: THIS CAN BE A VERY BAD APPROXIMATION, ESPECIALLY FOR LIGHT MATERIALS. No modification is applied for possible Doppler broadening effects on resonances for thermal and epithermal neutrons: again, this can be a bad approximation. The total cross section is rescaled according to the modified absorption and fission cross sections. d.3) Cross section rescaling is applied to the FLUKA materials at run time, that is if for example two 10-B materials are def- ined and both point to the same cross section data set, a possible temperature rescaling will affect only the FLUKA material indicated by MAT-PROP, while the other one will be unaffected, although they share the same low energy neutron cross section data set. d.4) Velocity setting is applied for compounds INDEPENDENTLY from cross section rescaling. That is, a (nominal) temperature input for a compound is fully meaningful and will be used for velocity computation. However cross section rescaling is applied on single constituents (of course!) and therefore... !!!!! IMPORTANT WARNING !!!! ...it cannot be used for compounds unless the corresponding neutron cross section data sets is a pre-mixed one (see Notes 4 to option LOW-MAT and 7 to COMPOUND). Otherwise a new compound must be created with new elemental constituents and the correction must be invoked for each constituent. * End_Devel_seq 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 (number based):
* 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 10. 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 AIR STERNHEI 10.5961 1.7418 4.2759 0.10914 3.3994 0. AIR2 * Start_Devel_seq Example 4 (number based):
* 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 The same example, name based:
*...+....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 * End_Devel_seq

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