Compound material layers in dd.build and dd.blanket

[adrianaghiozzi]

See detailed description in ProjectTorreyPines/FUSE.jl#540

[imbeauf]

Hello, I think it would be better to use the material identifier of IMAS, instead of just giving the material name.

See the existing list in utilities/materials_identifier.xml

Then we have the choice of either creating a material array of structure and replace "name" by a "type" identifier structure with (name, index, description), or to have two sibling nodes:

material(:) --> the identifier structure with (name, index, description)
material_volume_fraction(:) --> Volume fraction of each material entering the composition

[orso82]

here's the link to the materials_identifier.xml

[orso82]

@imbeauf materials are tricky. The issue with using identifiers is that with materials there's virtually an infinite number of options.

For context, in FUSE we use the materials' name to then get the properties of the materials from the FusionMaterials.jl package.