/gamos/setParam GmGeometryFromText:FileName exercise1a.geom
/gamos/geometry GmGeometryFromText
/gamos/physicsList G4QGSP_BIC_HP
 
/gamos/generator GmGenerator

/run/initialize

/gamos/generator/addSingleParticleSource source neutron 1*MeV
/gamos/generator/directionDist source GmGenerDistDirectionConst  0. 0. 1.
/gamos/generator/positionDist source GmGenerDistPositionPoint 0. 0. 0. 

/gamos/userAction GmKillAllUA GmSecondaryFilter

#####  Use user action SHNthValueLayerUA
### SHNthValueLayerUA needs GmClassifierByAncestors (see User's Guide)
/gamos/classifier ancesC GmClassifierByAncestors 1 1000 
### SHNthValueLayerUA needs GmExitLogicalVolumeFilter (see User's Guide) 
/gamos/filter exitshieldF GmExitLogicalVolumeFilter shield

### layer width must be the same as geometry
/gamos/setParam SHNthValueLayerUA_exitshieldF_ancesC:LayerWidth 1.
/gamos/setParam SHNthValueLayerUA_exitshieldF_ancesC:Reductions 10.
/gamos/userAction SHNthValueLayerUA exitshieldF ancesC

/gamos/setParam GmCountTracksUA:EachNEvent 1000
/gamos/userAction GmCountTracksUA

/run/beamOn 10000