Materials¶

There are four predefined materials in MULASSIS: Vacuum, Air, Aluminium and Silicon:

    PreInit> /geometry/material/list
    There are  4 materials defined.
         Material Index   1         Vacuum  density: 1e-022 mg/cm3
         Material Index   2            Air  density:   1.29 mg/cm3
         Material Index   3      Aluminium  density:    2.7 g/cm3
         Material Index   4        Silicon  density:   2.33 g/cm3

    PreInit>

In addition there are numerous predefined NIST materials from the Geant4 distribution:

    PreInit> /geometry/material/listNIST compound

    ###    Compound Materials from the NIST Data Base    ##
    =======================================================
     Ncomp Name  ChFormula        density(g/cm^3)  I(eV)
    =======================================================
    6  G4_A-150_TISSUE  1.127     65.1
                  1     0.101327
                  6     0.7755
                  7     0.035057
                  8     0.0523159
                  9     0.017422
                  20     0.018378
    3  G4_ACETONE  0.7899     64.2
                  1     0.104122
                  6     0.620405
                  8     0.275473
    2  G4_ACETYLENE  0.0010967     58.2
                  1     0.077418
                  6     0.922582
    3  G4_ADENINE  1.35     71.4
                  1     0.037294
                  6     0.44443
                  7     0.518276
    ..........
    PreInit> /geometry/material/addNIST G4_ACETONE
     Material:G4_ACETONE added from G4NistManager tables.
    PreInit>

New materials can be added with the command /geometry/material/add, e.g.

    PreInit> /geometry/material/add Water H2-O 1.

     Material:Water with formula: H2-O added!
         Nb of Material = 5
         Nb of Isotope =  0
         Nb of Element =  3

    PreInit> /geometry/material/list
    There are  5 materials defined.
         Material Index   1         Vacuum  density: 1e-022 mg/cm3
         Material Index   2            Air  density:   1.29 mg/cm3
         Material Index   3      Aluminium  density:    2.7 g/cm3
         Material Index   4        Silicon  density:   2.33 g/cm3
         Material Index   5          Water  density:      1 g/cm3
    PreInit>

The required parameters of the command are in the order of name; chemical formula; and density. The name is chosen by the user, and should be unique. The chemical composition uses a special syntax comprising: atomic symbol, isotope between brackets if required, stoichiometric proportion, and a hyphen to separate the different elements. The first letter for the chemical symbol can be upper case or lower case, the second must be lower case, i.e. “Na” and “na” will work but not “NA”. Isotope and stoichiometry are defined by integers only, i.e. you cannot use real numbers for stoichiometry. If the integer identifying the stoichiometric proportion is omitted, it will be assumed the value is unity. For example:

Na(24)1-Cl1, is equivalent to Na(24)-Cl (either specifically selecting the Na-24 radioisotope).

Bi4-Ge3-O12 (for bismuth germanate)

H(2)2-O1, is equivalent to H(2)2-O (heavy water).

The density of the material should be defined in units of g/cm³.

There are additional optional parameters of the material that the user can specify: state, temperature and pressure. Please refer to Geometry Commands for a full explanation of the command.

Mulassis/ml-v02-00/r342