Introduction Resources

• http://geant4.cern.ch/geant4/collaboration/working_groups/geometry/training/D2-Basics.pdf

Solid LV PV

• LV is everything but the position

Geometrical Hierarchy

• Position and rotation of the daughter volume is described with respect to the local coordinate system of the mother volume
• The origin of the mother’s local coordinate system is at the center of the mother volume
• Daughter volumes cannot protrude from the mother volume
• Daughter volumes cannot overlap
• Logical volume of mother knows the daughter volumes it contains
  • It is uniquely defined to be their mother volume
  • If the logical volume of the mother is placed more than once, all daughters appear by definition in all these physical instances of the mother
• The origin of the global coordinate system is at the center of the world volume

Touchables

A touchable for a volume serves the purpose of providing a unique identification for a detector element. Via copy numbers eg A.3/B.2/C.1