FLUKA: 5.2} Pre-defined materials
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5.2} Pre-defined materials
--------------------------
Materials can be easily defined by option MATERIAL by assigning a density, a
name, a code number (compulsory only if the input has been defined as purely
numeric), and, in the case of single elements, an atomic number and an atomic
weight. For compounds, the MATERIAL option card must be accompanied by a
COMPOUND definition referred to the same material name. If low-energy neutrons
(E < 20 MeV) need to be transported, the chosen name of a single element
material must coincide with that of one for which cross sections are available
(see Table in 10}).
However, for user's convenience, 25 common single-element materials are
already pre-defined (see Table below): they are assigned a default density,
name and code number even if no MATERIAL definition has been given. The user
can override any of these if desired (but cannot change the code number), and
can add more material definitions by means of one or more MATERIAL cards. The
only constraints are:
there may not be any gap in the numbering sequence from 25 onwards. If the
input is name-based, omitting the material number is the easiest way to
ensure this, since the code will assign a correct number automatically.
number (if expressed explicitly) must be equal to that of the pre-defined
material.
Note that the above constraints can be ignored if the input is name-based and
the material number in the MATERIAL option is left blank. In that case, the
material name must be used in all relevant command (e.g. ASSIGNMAt, COMPOUND).
In addition to the 25 pre-defined single-element materials, some pre-defined
compounds are available. For them, the stopping power of charged particles is
not calculated directly from the component elements by the Bragg formula, but
the Sternheimer parameters and the ionisation potential recommended by ICRU
[ICRU84] are applied. Composition is also that recommended by ICRU. Reference
to these pre-defined compounds is normally by name and no MATERIAL and
COMPOUND cards are needed: if the input is explicitly number-based only (via
command GLOBAL), a number needs to be assigned to them using a MATERIAL card,
of course leaving no gaps in the numbering sequence.
If a user defines a compound with the same name and similar composition, the
code automatically "matches" its stopping power parameters to those of the
pre-defined one. It is also possible to modify the Sternheimer parameters with
command STERNHEIme and the ionisation potential with MAT-PROP.
List of pre-defined single-element FLUKA materials
--------------------------------------------------
FLUKA name FLUKA Common name A Z Density
number [g/cm^3]
BLCKHOLE 1 Blackhole or External Vacuum 0 0 0
VACUUM 2 Vacuum or Internal Vacuum 0 0 0
HYDROGEN 3 Hydrogen 1.00794 1. 0.0000837
HELIUM 4 Helium 4.002602 2. 0.000166
BERYLLIU 5 Beryllium 9.012182 4. 1.848
CARBON 6 Carbon 12.0107 6. 2.000
NITROGEN 7 Nitrogen 14.0067 7. 0.00117
OXYGEN 8 Oxygen 15.9994 8. 0.00133
MAGNESIU 9 Magnesium 24.3050 12. 1.740
ALUMINUM 10 Aluminium 26.981538 13. 2.699
IRON 11 Iron 55.845 26. 7.874
COPPER 12 Copper 63.546 29. 8.960
SILVER 13 Silver 107.8682 47. 10.500
SILICON 14 Silicon 28.0855 14. 2.329
GOLD 15 Gold 196.96655 79. 19.320
MERCURY 16 Mercury 200.59 80. 13.546
LEAD 17 Lead 207.2 82. 11.350
TANTALUM 18 Tantalum 180.9479 73. 16.654
SODIUM 19 Sodium 22.989770 11. 0.971
ARGON 20 Argon 39.948 18. 0.00166
CALCIUM 21 Calcium 40.078 20. 1.550
TIN 22 Tin 118.710 50. 7.310
TUNGSTEN 23 Tungsten 183.84 74. 19.300
TITANIUM 24 Titanium 47.867 22. 4.540
NICKEL 25 Nickel 58.6934 28. 8.902
List of pre-defined ICRU compounds
----------------------------------
Fluka name Common name Density
[g/cm^3]
WATER Water 1.0
POLYSTYR Polystyrene 1.06
PLASCINT Plastic scintillator 1.032
PMMA Polymethyl methacrylate, Plexiglas, Lucite, Perspex 1.19
BONECOMP Compact bone 1.85
BONECORT Cortical bone 1.85
MUSCLESK Skeletal muscle 1.04
MUSCLEST Striated muscle 1.04
ADTISSUE Adipose tissue 0.92
KAPTON Kapton polyimide film 1.42
POLYETHY Polyethylene 0.94
AIR Dry air at NTP conditions 0.00120479
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