diff --git a/src/cosima/inc/MCParameterFile.hh b/src/cosima/inc/MCParameterFile.hh
index a6904e26..b3c07c25 100644
--- a/src/cosima/inc/MCParameterFile.hh
+++ b/src/cosima/inc/MCParameterFile.hh
@@ -124,6 +124,11 @@ public:
   bool DiscretizeHits() const { return m_DiscretizeHits; }
   /// Return the watched volumes list
   vector<MString> GetStoreSimulationInfoWatchedVolumes() const { return m_StoreSimulationInfoWatchedVolumes; }
+  /// Return true if you want to set a maximum number of IA per event (e.g 10000)
+  bool AllowMaxNbofIAs() const { return m_AllowMaxNbofIAs; }
+  /// Return the maximum number of IA allowed by event
+  int MaxNIAs() const { return m_MaxNIAs; }
+  
   
   /// Set the pre-trigger mode (either store everything, only events with hits, or fully pretriggered events)
   void SetPreTriggerMode(const int PreTriggerMode) { m_PreTriggerMode = PreTriggerMode; }
@@ -259,6 +264,12 @@ private:
 
   /// The activation time constant: The time during which decays are consindered coincident
   double m_DetectorTimeConstant;
+  
+  ///If you want to set a maximum number of IA
+  bool m_AllowMaxNbofIAs;
+  /// Maximum number of IA for an event
+  int m_MaxNIAs;
+  
 };
 
 #endif
diff --git a/src/cosima/src/MCEventAction.cc b/src/cosima/src/MCEventAction.cc
index f646f166..6bdd2776 100644
--- a/src/cosima/src/MCEventAction.cc
+++ b/src/cosima/src/MCEventAction.cc
@@ -76,6 +76,10 @@ MCEventAction::MCEventAction(MCParameterFile& RunParameters, const bool Zip, con
   
   m_PreTriggerMode = RunParameters.GetPreTriggerMode();
   
+  m_AllowMaxNbofIAs = RunParameters.AllowMaxNbofIAs();
+  m_MaxNIAs = RunParameters.MaxNIAs();
+  
+  
   if (RunParameters.StoreScientific() == true) {
     m_StoreScientificPrecision = RunParameters.StoreScientificPrecision();
   } else {
@@ -450,6 +454,19 @@ void MCEventAction::AddIA(G4String ProcessID,
   if (ProcessID == "ESCP") {
     AddEnergyLoss(NewKin);
   }
+  
+  
+  //If the number of IA is too much we abort the event
+  //This prevent to have event with 50K or even more hits 
+  if(m_AllowMaxNbofIAs==true){
+      if(m_Event->GetNIAs() > m_MaxNIAs){
+          mdebug<<"Number of IA is > "<<m_MaxNIAs<<" Event aborted !"<<endl;
+          //cout<<m_Event->ToString()<<endl;
+          const_cast<G4Event*>(G4RunManager::GetRunManager()->GetCurrentEvent())->SetEventAborted();
+          m_IsAborted = true;
+      }
+    }
+  
 }
 
 /******************************************************************************
@@ -522,7 +539,7 @@ void MCEventAction::AbortEvent()
 void MCEventAction::EndOfEventAction(const G4Event* Event)
 {
   // Let's store the events...
-  size_t h;
+  G4int h;
   G4String Text;
   
   MCRun& Run = m_RunParameters.GetCurrentRun();
diff --git a/src/cosima/src/MCParameterFile.cc b/src/cosima/src/MCParameterFile.cc
index 4cdb2ea6..7c582b8c 100644
--- a/src/cosima/src/MCParameterFile.cc
+++ b/src/cosima/src/MCParameterFile.cc
@@ -74,7 +74,9 @@ MCParameterFile::MCParameterFile() : MParser(' ', true),
                                      m_CreateCrossSectionFiles(false),
                                      m_CrossSectionFileDirectory(""),
                                      m_ActiveRun(0),
-                                     m_DetectorTimeConstant(1*ns)
+                                     m_DetectorTimeConstant(1*ns),
+				                     m_AllowMaxNbofIAs(false),
+				                     m_MaxNIAs(1000000)
 {
   // Intentionally left blank
 }
@@ -395,6 +397,18 @@ bool MCParameterFile::Parse()
              " Number of tokens is not correct!");
         return false;
       }
+    } else if (T->IsTokenAt(0, "AllowMaxNbofIAs", true) == true) {
+      if (T->GetNTokens() == 3) {
+        m_AllowMaxNbofIAs = T->GetTokenAtAsBoolean(1);
+        if (m_AllowMaxNbofIAs == true) {
+          m_MaxNIAs = T->GetTokenAtAsInt(2);
+        }
+        mdebug<<"Allow a maximum number of "<< m_MaxNIAs <<" IA per events : "<<((m_StoreSimulationInfoIonization == true) ? "true" : "false")<<endl;
+      } else {
+        Typo(i, "Cannot parse token AllowMaxNbofIAs correctly:"
+             " Number of tokens is not correct!");
+        return false;
+      }
     } else if (T->IsTokenAt(0, "StoreSimulationInfoWatchedVolumes", true) == true ||
                T->IsTokenAt(0, "StoreSimulationInfoWatchedVolume", true) == true) {
       if (T->GetNTokens() >= 2) {