Import Geant4 11.3.2 source tree

source/processes/decay/History

@@ -1,9 +1,13 @@
 # Category 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!
 
+-------------------------------------------------------------------------------
+
+## 2025-04-03 Alvaro Tolosa-Delgado (decay-V11-02-00)
+- Remove approximation in calculation of G4Decay path length, fix issue #2645
 
 ## 2021-12-10 Ben Morgan (decay-V11-00-00)
 - Change to new Markdown History format

source/processes/decay/include/G4Decay.hh

@@ -166,8 +166,6 @@ class G4Decay : public G4VRestDiscreteProcess
      //  2: More
 
   protected:
-    // HighestValue.
-    const G4double HighestValue;
  
     // Remainder of life time at rest
     G4double                 fRemainderLifeTime;

source/processes/decay/src/G4Decay.cc

@@ -62,7 +62,6 @@
 G4Decay::G4Decay(const G4String& processName)
                                :G4VRestDiscreteProcess(processName, fDecay),
 				verboseLevel(1),
-                                HighestValue(20.0),
 				fRemainderLifeTime(-1.0),
                                 pExtDecayer(nullptr)
 {
@@ -151,10 +150,7 @@ G4double G4Decay::GetMeanFreePath(const G4Track& aTrack,G4double, G4ForceConditi
     //calculate the mean free path 
     // by using normalized kinetic energy (= Ekin/mass)
      G4double   rKineticEnergy = aParticle->GetKineticEnergy()/aMass; 
-     if ( rKineticEnergy > HighestValue) {
-       // gamma >>  1
-       pathlength = ( rKineticEnergy + 1.0)* aCtau;
-     } else if ( rKineticEnergy < DBL_MIN ) {
+     if ( rKineticEnergy < DBL_MIN ) {
        // too slow particle
 #ifdef G4VERBOSE
        if (GetVerboseLevel()>1) {