Geant4 User's Guide for Application Developers - Geant4 - CERN

Detector Definition and ResponseG4GeometryManager::GetInstance()->SetWorldMaximumExtent(WorldExtent);where, WorldExtent is the actual maximum extent of the world volume used for placing the whole geometrysetup.Such call to G4GeometryManager must be done before defining any geometrical component of the setup (solidshape or volume), and can be done only once !The class G4GeometryTolerance is to be used for retrieving the actual values defined for tolerances, surface(Cartesian), angular or radial respectively:G4GeometryTolerance::GetInstance()->GetSurfaceTolerance();G4GeometryTolerance::GetInstance()->GetAngularTolerance();G4GeometryTolerance::GetInstance()->GetRadialTolerance();4.1.9. A Simple Geometry EditorGGE is the acronym for Geant4 Graphical Geometry Editor. GGE aims to assist physicists who have a littleknowledge on C++ and the Geant4 toolkit to construct his or her own detector geometry. In essence, GGE is madeup of a set of tables which can contain all relevant parameters to construct a simple detector geometry. Tablesfor scratch or compound materials, tables for logical and physical volumes are provided. From the values in thetables, C++ source codes are automatically generated.GGE provides methods to:1. construct a detector geometry including G4Element, G4Material, G4Solids, G4LogicalVolume,G4PVPlacement, etc.2. view the detector geometry using existing visualization system, DAWN3. keep the detector object in a persistent way, either in GDML format (currently only logical volumes are supported)or Java serialized format.4. produce corresponding C++ codes after the norm of Geant4 toolkit5. make a Geant4 executable, in collaboration with another component of MOMO, i.e., GPE, or Geant4 PhysicsEditor.GGE can be found in the standard Geant4 distribution under the $G4INSTALL/environments/MO-MO/MOMO.jar. JRE (Java Run-time Environment) is prerequisite to run MOMO.jar, Java archive file of MO-MO. MOMO contains GGE, GPE, GAG and other helper tools. Further information is available from the Webpages below.MOMO = GGE + GPE + GAG: http://www-geant4.kek.jp/~yoshidah4.1.9.1. Materials: elements and mixturesGGE provides the database of elements in the form of the periodic table, from which users can select element(s) toconstruct new materials. They can be loaded, used, edited and saved as Java persistent objects or in a GDML file.In $G4INSTALL/enviroments/MOMO, a pre-constructed database of materials taken from the PDG book,PDG.xml is present.Users can also create new materials either from scratch or by combining other materials.• By selecting an element in the periodic table, default values as shown below are copied to a row in the table.Use Name A Z Density Unit State TemperatureUnitPressure UnitUse marks the used materials. Only the elements and materials used in the logical volumes are kept in thedetector object and are used to generate C++ constructors.• By selecting multiple elements in the periodic table, a material from a combination of elements is assigned toa row of the compound material table. The minimum actions user have to do is to give a name to the materialand define its density.105