diff --git a/NPSimulation/EventGenerator/EventGeneratorIsotropic.cc b/NPSimulation/EventGenerator/EventGeneratorIsotropic.cc
index ff9013b94257a40b84e3c5a08b56c29c6cd442cd..f1e070aa212b9662f08c4813a33cab2a14fd3cf3 100644
--- a/NPSimulation/EventGenerator/EventGeneratorIsotropic.cc
+++ b/NPSimulation/EventGenerator/EventGeneratorIsotropic.cc
@@ -69,9 +69,6 @@ EventGeneratorIsotropic::SourceParameters::SourceParameters(){
   m_particle     = NULL;
   m_direction    = 'z' ;
   m_SourceProfile = "Gauss" ;
-  m_DecayLaw     = "off";
-  m_ActivityBq   = 1.  ;
-  m_TimeWindow   = 1.e-9 ;
 }
 
 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
@@ -131,12 +128,6 @@ void EventGeneratorIsotropic::ReadConfiguration(NPL::InputParser parser){
         it->m_SigmaZ=blocks[i]->GetDouble("SigmaZ","mm");
       if(blocks[i]->HasToken("Multiplicity"))
         it->m_Multiplicity=blocks[i]->GetVectorInt("Multiplicity");
-      if(blocks[i]->HasToken("DecayLaw"))
-        it->m_DecayLaw=blocks[i]->GetString("DecayLaw");
-      if(blocks[i]->HasToken("ActivityBq"))
-        it->m_ActivityBq=blocks[i]->GetDouble("ActivityBq","Bq");
-      if(blocks[i]->HasToken("TimeWindow"))
-        it->m_TimeWindow=blocks[i]->GetDouble("TimeWindow","s");
     }
     else{
       cout << "ERROR: check your input file formatting \033[0m" << endl;
@@ -165,13 +156,7 @@ void EventGeneratorIsotropic::ReadConfiguration(NPL::InputParser parser){
 void EventGeneratorIsotropic::GenerateEvent(G4Event*){
 
   for(auto& par : m_Parameters) {
-    double delta_t = 0.;
-    bool   DecayOn = true;
     for(unsigned int p=0; p<par.m_particleName.size(); p++){
-      double step_t = 1.e-2 / par.m_ActivityBq; // [s]
-      if(par.m_DecayLaw=="on"){
-        par.m_Multiplicity[p] = ((int)(par.m_TimeWindow / step_t) == 0) ? 1 : (int)(50.e-9 / step_t);
-      }
       for(int i=0; i<par.m_Multiplicity[p]; i++){
         par.m_particle=NULL;
         if(par.m_particle==NULL){
@@ -185,13 +170,8 @@ void EventGeneratorIsotropic::GenerateEvent(G4Event*){
             NPL::Nucleus* N = new NPL::Nucleus(par.m_particleName[p]);
             par.m_particle = G4ParticleTable::GetParticleTable()->GetIonTable()->GetIon(N->GetZ(), N->GetA(),par.m_ExcitationEnergy[p]);
             delete N;
-            if(par.m_DecayLaw == "on" && i>0){
-              delta_t = i*step_t;
-              DecayOn = !(par.m_DecayLaw == "on" && RandFlat::shoot() > 1.e-2);
-            }
           }
         }
-        if(!DecayOn) continue;
         G4double cos_theta_min   = cos(par.m_HalfOpenAngleMin);
         G4double cos_theta_max   = cos(par.m_HalfOpenAngleMax);
         G4double cos_theta       = cos_theta_min + (cos_theta_max - cos_theta_min) * RandFlat::shoot();
@@ -249,7 +229,6 @@ void EventGeneratorIsotropic::GenerateEvent(G4Event*){
           momentum_x = cos(theta)             ;
         }
 
-
         NPS::Particle particle(par.m_particle, theta, particle_energy, G4ThreeVector(momentum_x, momentum_y, momentum_z), G4ThreeVector(x0, y0, z0));
         m_ParticleStack->AddParticleToStack(particle);
       }
diff --git a/NPSimulation/EventGenerator/EventGeneratorIsotropic.hh b/NPSimulation/EventGenerator/EventGeneratorIsotropic.hh
index 2e0cab718bac2e88d7f7baf6bbdb10e9046b89fd..d1161a3f25687e21b806c70ca655136dc31b1b09 100644
--- a/NPSimulation/EventGenerator/EventGeneratorIsotropic.hh
+++ b/NPSimulation/EventGenerator/EventGeneratorIsotropic.hh
@@ -72,9 +72,6 @@ private:    // Source parameter from input file
       vector<G4double>         m_ExcitationEnergy ;  // Excitation energy of the emitted particle
       vector<string>           m_particleName     ;
       vector<G4int>            m_Multiplicity     ;
-      TString                  m_DecayLaw         ;  // [on]: mult follows the decay law controlled by T1/2 [off]: fix mult
-	    G4double                 m_ActivityBq       ;  // if m_DecayLaw = "on" gives here the Activity in Bq of the sample
-      G4double                 m_TimeWindow       ;  // DAQ time window during we see the alpha pile-up
     };
 	  vector<SourceParameters> m_Parameters       ;
     ParticleStack*           m_ParticleStack    ;