Set birks constants without patching geant4
Interfaces:
- geant4:
G4Material* m; m->GetIonisation()->SetBirksContant(value);
Problems:
- G4GDMLReadMaterials does not support
<material>
properties relevant to ionization beyondMEE
- dd4hep::Geant4Converter doesn't set any ionization properties beyond MEE (and even this it doesn't actually set them but lets TGeo do the work using GDML)
Possible strategy:
- dd4hep::Material has support for Property, which is a TGDMLMatrix pointer. We could define the birks constant as a material property table, similar to index of refraction for optical materials. That's a bit of an abuse of the material property tables since birks constants are never tables (or at least energy-dependence is not supported in geant4).