physics: increase default time threshold for decays

back to the old default of Geant4 11.0 - 11.1

CMakeLists.txt

@@ -70,6 +70,12 @@ if(Geant4_FOUND)
   message(STATUS "Found Geant4 v" ${Geant4_VERSION})
 endif()
 
+if (Geant4_VERSION VERSION_GREATER_EQUAL "11.2.0")
+    set(RMG_HAS_GEANT4_11_2_OR_LATER 1)
+else()
+    set(RMG_HAS_GEANT4_11_2_OR_LATER 0)
+endif()
+
 # check for optional components
 find_package(Geant4 QUIET OPTIONAL_COMPONENTS hdf5 usolids multithreaded gdml ui_all vis_all)
 

cmake/RMGConfig.hh.in

@@ -12,5 +12,6 @@
 #define RMG_HAS_BXDECAY0_THREADSAFE @BxDecay0_THREADSAFE@
 #define RMG_HAS_GDML @RMG_HAS_GDML@
 #define RMG_HAS_HDF5 @RMG_HAS_HDF5@
+#define RMG_HAS_GEANT4_11_2_OR_LATER @RMG_HAS_GEANT4_11_2_OR_LATER@
 
 #endif

src/RMGPhysics.cc

@@ -36,6 +36,7 @@
 #include "G4HadronPhysicsQGSP_BIC_AllHP.hh"
 #include "G4HadronPhysicsQGSP_BIC_HP.hh"
 #include "G4HadronPhysicsShielding.hh"
+#include "G4HadronicParameters.hh"
 #include "G4HadronicProcessStore.hh"
 #include "G4IonConstructor.hh"
 #include "G4IonPhysics.hh"
@@ -65,6 +66,7 @@
 #include "G4StoppingPhysics.hh"
 #include "G4ThermalNeutrons.hh"
 
+#include "RMGConfig.hh"
 #include "RMGLog.hh"
 #include "RMGNeutronCaptureProcess.hh"
 #include "RMGOpWLSProcess.hh"
@@ -179,6 +181,14 @@ void RMGPhysics::ConstructProcess() {
 
   // Hadronic Physics
 
+#if RMG_HAS_GEANT4_11_2_OR_LATER
+  // Geant4 11.2 changed this to 1 year, which is rather short for our use case.
+  // Reset it to the old default of Geant4 11.0/11.1.
+  // note: this still might be too short for very rare decays, but it can be increased with
+  // a macro command.
+  G4HadronicParameters::Instance()->SetTimeThresholdForRadioactiveDecay(1.0e+27 * u::ns);
+#endif
+
   /*
   G4ParticleHPManager::GetInstance()->SetSkipMissingIsotopes( false );
   G4ParticleHPManager::GetInstance()->SetDoNotAdjustFinalState( true );