- fixed logic for writing out MCParticles:

   - don't write particles created in calo
     unless scattered back into tracker)
   - don't write particles created in tracker
     if below MinimalKineticEnergy ( Geant4ParticleHandler)

DDG4/plugins/Geant4TCUserParticleHandler.cpp

@@ -12,6 +12,7 @@
 // Framework include files
 #include "DDG4/Geant4UserParticleHandler.h"
 
+
 /*
  *   DD4hep namespace declaration
  */
@@ -70,6 +71,7 @@ namespace DD4hep {
 #include "DDG4/Geant4Particle.h"
 #include "DDG4/Factories.h"
 
+
 using namespace DD4hep::Simulation;
 DECLARE_GEANT4ACTION(Geant4TCUserParticleHandler)
 
@@ -83,16 +85,31 @@ Geant4TCUserParticleHandler::Geant4TCUserParticleHandler(Geant4Context* context,
 
 /// Post-track action callback
 void Geant4TCUserParticleHandler::end(const G4Track* /* track */, Particle& p)  {
-  double r_end  = sqrt(p.vex*p.vex + p.vey*p.vey);
-  double z_end  = fabs(p.vez);
-  // Keep particles with end-vertex inside tracking (including back-scattered particles)
-  if ( r_end <= m_rTracker && z_end <= m_zTracker )  {
-    return;
-  }
+
+
   double r_prod = sqrt(p.vsx*p.vsx + p.vsy*p.vsy);
   double z_prod = fabs(p.vsz);
-  // Otherwise: reject particles created outside the tracking volume.
-  if ( r_prod > m_rTracker || z_prod > m_zTracker )  {
+  bool starts_in_trk_vol = ( r_prod <= m_rTracker && z_prod <= m_zTracker )  ;
+
+  // created in tracking volume but below energy cut
+  if( starts_in_trk_vol && ! (p.reason&G4PARTICLE_ABOVE_ENERGY_THRESHOLD)  ){
+    
+    p.reason = 0 ;
+    return;
+  }
+
+  double r_end  = sqrt(p.vex*p.vex + p.vey*p.vey);
+  double z_end  = fabs(p.vez);
+  bool ends_in_trk_vol =  ( r_end <= m_rTracker && z_end <= m_zTracker ) ;
+
+  // created and ended in calo
+  if( !starts_in_trk_vol && !ends_in_trk_vol ){
+    
     p.reason = 0;
+    return ;
   }
+  
+  //fg: backscatter ??
+  // if( !starts_in_trk_vol &&  ends_in_trk_vol ){  keep ?  } 
+
 }