:P POSX 8. :P A_H 1.00797 :P A_O 15.9994 // Define single elements :ELEM Hydrogen H 1. $A_H // Define elements from isotopes :ISOT N 7 14 14.0031 :ISOT N_2 7 15 15.0001 :ELEM_FROM_ISOT Nytrogen N 2 N 0.99632 N_2 0.00368 :ISOT O 8 16 15.9949 :ISOT O_2 8 17 16.9991 :ISOT O_3 8 18 17.9992 :ELEM_FROM_ISOT Oxygen O 3 O 0.99757 O_2 0.00038 O_3 0.00205 // Define single material :MATE Hydrogen 1 1. 8.37480e-5 // Define material mixtures // Define material mixture of elements by weight :MIXT WaterW_EE 1. 2 // Use Hydrogen element built here and Oxygen element from GEANT4 NIST Hydrogen 2.*$A_H/(2.*$A_H+$A_O) O $A_O/(2.*$A_H+$A_O) // Define material mixture of element and material by weight :MIXT WaterW_EM 1. 2 // Use Hydrogen element built here and Oxygen material from GEANT4 NIST Hydrogen 2.*$A_H/(2.*$A_H+$A_O) G4_O $A_O/(2.*$A_H+$A_O) // Define material mixture of elements by number of atoms :MIXT_BY_NATOMS WaterNA 1 2 Hydrogen 2 Oxygen 1 // Define material mixture of material mixtures :MIXT_BY_NATOMS CO2 1.8182E-3 2 C 1 O 2 :MIXT_BY_VOLUME H-CO2 (1.214E-03+1.8182E-3)/2. 2 // Use Hydrogen material (MIXT_BY_VOLUME does not use elements) Hydrogen 0.5 CO2 0.5 // Use materials (if a material is not used it will not be created as a Geant4 object) :ROTM R00 90. 0. 90. 90. 0. 0. :VOLU world BOX 100. 100. 100. WaterW_EE :VOLU "my tube" TUBS 0. 10. 20. 0. 360. WaterW_EM :PLACE "my tube" 1 world R00 0. 0. $POSX :VOLU sphere ORB 5. WaterNA :PLACE sphere 1 "my tube" R00 0. 1. $POSX :VOLU sphere2 ORB 5. H-CO2 :PLACE sphere2 1 "my tube" R00 0. 1. -$POSX // Switch on overlap checking for all volumes :CHECK_OVERLAPS * ON