Import Geant4 11.1.1 source tree

source/physics_lists/constructors/decay/History

@@ -1,8 +1,22 @@
 # Category phys-ctor-decay History
 
 See `CONTRIBUTING.rst` for details of **required** info/format for each entry,
-which **must** added in reverse chronological order (newest at the top). It must **not**
-be used as a substitute for writing good git commit messages!
+which **must** added in reverse chronological order (newest at the top).
+It must **not** be used as a substitute for writing good git commit messages!
+
+-------------------------------------------------------------------------------
+
+## 2023-01-11 Alberto Ribon (phys-ctor-decay-V11-00-04)
+- G4RadioactiveDecayPhysics : assigned the RadioactiveDecay process
+  to G4Triton (which is the only light ion that decays).
+  Note: before, triton did not have beta decay, i.e. it was wrongly
+  treated as stable even when radioactive decay physics was enabled;
+  anti_triton did not, and still does not, have beta decay
+  (because RadioactiveDecay, in its current implementation, does
+  not handle any kind of anti-ions): in practice, this is an acceptable
+  approximation because of its relatively long lifetime and the fact
+  that annihilation and nuclear capture are more likely to happen
+  before decay.
 
 ## 2022-11-16 Vladimir Ivanchenko (phys-ctor-decay-V11-00-03)
 - added calls to G4EmBuilder and G4PhysListUtil in order to 

source/physics_lists/constructors/decay/src/G4RadioactiveDecayPhysics.cc

@@ -40,6 +40,7 @@
 #include "G4DeexPrecoParameters.hh"
 #include "G4NuclideTable.hh"
 #include "G4PhysListUtil.hh"
+#include "G4Triton.hh"
 
 // factory
 #include "G4PhysicsConstructorFactory.hh"
@@ -99,6 +100,15 @@ void G4RadioactiveDecayPhysics::ConstructProcess()
 
   G4PhysicsListHelper::GetPhysicsListHelper()->
     RegisterProcess(new G4RadioactiveDecay(), G4GenericIon::GenericIon());
+
+  // Triton (which is not a generic ion) is the only light ion that decays.
+  // Note that the anti_triton does not have beta decay, because RadioactiveDecay,
+  // in its current implementation, does not handle any kind of anti-ions: 
+  // in practice, this is an acceptable approximation because of its relatively
+  // long lifetime and the fact that annihilation and nuclear capture
+  // are more likely to happen before decay.
+  G4PhysicsListHelper::GetPhysicsListHelper()->
+    RegisterProcess(new G4RadioactiveDecay(), G4Triton::Triton());
 }
 
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