W pliku     src/MyDetectorConstruction.cc    (zmiany kolorem czerwonym)
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#include "G4NistManager.hh"
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void MyDetectorConstruction::SetupGeometry()
{
  // NIST definition of air
  //  G4Material* air = G4Material::GetMaterial("Air");

  G4NistManager* man = G4NistManager::Instance();
  G4Material* air = man->FindOrBuildMaterial("G4_AIR");
  G4cout << air << G4endl;

  // World volume
  G4Box* worldSolid = new G4Box("World_Solid",           // Name
                                2.0*m, 2.0*m, 2.0*m);    // Half lengths
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