diff --git a/doc/musrSim.pdf b/doc/musrSim.pdf
index 94ee1ad..5962a05 100644
Binary files a/doc/musrSim.pdf and b/doc/musrSim.pdf differ
diff --git a/doc/musrSim.tex b/doc/musrSim.tex
index d58f55e..b1f5da9 100644
--- a/doc/musrSim.tex
+++ b/doc/musrSim.tex
@@ -126,6 +126,7 @@ in the macro file:
 
 By default, the output of the simulation is written out in the subdirectory ``data'' with
 the name ``musr\_RUNNUMBER.root''.
+(Note that the execution of the simulation can be terminated gently by creating a file ``RUNNUMBER.stop'' in the working directory.)
 
 \section{Conventions}
 The default units of the musrSim in both the macro file (RUNNUMBER.mac) and in the Root tree 
@@ -766,7 +767,10 @@ Three special volumes ``Target, M0, M1 and M2''.
 	the job will be terminated gently if its physical execution time
 	exceeds \emph{timeMax}.  
 	Note that the units of \emph{timeMax} are seconds,
-	and the default value is set to 85000\,s (23\,hours, 37\,minutes).
+	and the default value is set to 85000\,s (23\,hours, 37\,minutes).\\
+	(Note that the simulation can also be terminated gently by creating a file
+         ``RUNNUMBER.stop'' in the working directory, where RUNNUMBER matches the 
+	run number specified in the name of the macro file.)
 \end{description}
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \section{Output root tree variables}
diff --git a/include/musrParameters.hh b/include/musrParameters.hh
index eb33d84..8c0efb2 100644
--- a/include/musrParameters.hh
+++ b/include/musrParameters.hh
@@ -34,6 +34,7 @@ class musrParameters {
     static musrParameters* GetInstance();
 
     static G4String mySteeringFileName;      // name of the steering file (e.g. the *.mac file)
+    static G4String myStopFileName;      // name of the stop file (e.g. the *.stop file), which will stop the run if it is created
     static G4bool storeOnlyEventsWithHits;   // variable specifying whether to store interesting 
                                              // or all events into the ROOT tree. (default = true)
     static G4int  storeOnlyEventsWithHitInDetID; // simillar to "storeOnlyEventsWithHits".  The event is stored
diff --git a/src/musrEventAction.cc b/src/musrEventAction.cc
index af4edff..9130b9b 100644
--- a/src/musrEventAction.cc
+++ b/src/musrEventAction.cc
@@ -30,11 +30,14 @@
 #include "G4ios.hh"
 #include "G4TransportationManager.hh"
 #include "G4FieldManager.hh"
+#include "musrParameters.hh"
 #include "musrRootOutput.hh"
 #include "musrErrorMessage.hh"
 #include "musrSteppingAction.hh"
 #include "F04GlobalField.hh"
-#include "G4RunManager.hh"  // needed just in order to save random number generator seed
+#include "G4Run.hh"
+#include "G4RunManager.hh"
+#include <sys/stat.h>
 
 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
 
@@ -75,6 +78,13 @@ void musrEventAction::EndOfEventAction(const G4Event* evt)  {
   //  cout << ":." << flush;
   long thisEventNr = (long) evt->GetEventID();
   
+  // write out the root tree:
+  musrRootOutput* myRootOutput = musrRootOutput::GetRootInstance();
+  G4RunManager* fRunManager = G4RunManager::GetRunManager();
+  myRootOutput->SetRunID(fRunManager->GetCurrentRun()->GetRunID());
+  myRootOutput->SetEventID(fRunManager->GetCurrentEvent()->GetEventID());
+  myRootOutput->FillEvent();
+
   // get number of stored trajectories
   G4TrajectoryContainer* trajectoryContainer = evt->GetTrajectoryContainer();
   G4int n_trajectories = 0;
@@ -94,6 +104,19 @@ void musrEventAction::EndOfEventAction(const G4Event* evt)  {
     G4RunManager* fRunManager = G4RunManager::GetRunManager();
     fRunManager->AbortRun(true);
   }
+
+  // Stop the run, if the user wished that (by creating a file "RUNNUMBER.stop"
+  struct stat stFileInfo; 
+  if (stat((musrParameters::myStopFileName).c_str(),&stFileInfo)==0) {
+    // Stop the execution of the run - the file "RUNNUMBER.stop" was found
+    remove((musrParameters::myStopFileName).c_str());
+    char eMessage[200];
+    sprintf(eMessage,"musrEventAction::EndOfEventAction(): Request to stop the run was found (%s) ==> RUN STOPPED",musrParameters::myStopFileName.c_str());
+    musrErrorMessage::GetInstance()->musrError(WARNING,eMessage,false);
+    G4RunManager* fRunManager = G4RunManager::GetRunManager();
+    fRunManager->AbortRun(true);
+  }
+
   if (thisEventNr != 0 and thisEventNr%nHowOftenToPrintEvent == 0) {
     time_t curr=time(0);
     //char * ctime(const time_t * tp);
diff --git a/src/musrParameters.cc b/src/musrParameters.cc
index 40ba6b5..d389da2 100644
--- a/src/musrParameters.cc
+++ b/src/musrParameters.cc
@@ -30,6 +30,12 @@ musrParameters::musrParameters(G4String steeringFileName)
   pointerToParameters = this;
   boolG4RegionRequested = false;
   mySteeringFileName = steeringFileName;
+  myStopFileName = mySteeringFileName;  
+  //  myStopFileName.replace(myStopFileName.end()-2,myStopFileName.end(),"stop");
+  //  Int_t lengthOfFileName=
+  //  myStopFileName.replace(3,5,"stop");
+  myStopFileName.replace(myStopFileName.length()-3,myStopFileName.length()-1,"stop");
+
 
   // Read in the parameters, which have to be known before the detector construction is run
   // (and therefore the parameters can not be read in in the musrDetectorConstruction.cc class).
@@ -98,7 +104,8 @@ musrParameters* musrParameters::GetInstance() {
   return pointerToParameters;
 }
 
-G4String musrParameters::mySteeringFileName="Unset"; 
+G4String musrParameters::mySteeringFileName="Unset";
+G4String musrParameters::myStopFileName="Unsetblablabla034tdk40928jfmfnakfh921djf02UNSET";
 G4bool   musrParameters::storeOnlyEventsWithHits=true;
 G4int    musrParameters::storeOnlyEventsWithHitInDetID=0;
 G4double musrParameters::signalSeparationTime=100*nanosecond;
diff --git a/src/musrRootOutput.cc b/src/musrRootOutput.cc
index 2acaf24..145dbae 100644
--- a/src/musrRootOutput.cc
+++ b/src/musrRootOutput.cc
@@ -25,6 +25,7 @@
 #include "G4RunManager.hh"
 #include "G4Run.hh"
 #include "musrErrorMessage.hh"
+#include "musrParameters.hh"
 
 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
 
@@ -310,7 +311,9 @@ void musrRootOutput::FillEvent() {
   htest5->Fill(atan2(posIniMomy_t,posIniMomx_t));
   htest6->Fill(atan2(sqrt(posIniMomx_t*posIniMomx_t+posIniMomy_t*posIniMomy_t),posIniMomz_t));
   if (weight_t>0.) {
-    rootTree->Fill();
+    if ( !((musrParameters::storeOnlyEventsWithHits)&&(det_n<=0)) ) {
+      rootTree->Fill();
+    }
   }
 }
 
diff --git a/src/musrScintSD.cc b/src/musrScintSD.cc
index d1c1349..5cd5697 100644
--- a/src/musrScintSD.cc
+++ b/src/musrScintSD.cc
@@ -29,8 +29,6 @@
 #include "G4ios.hh"
 #include <algorithm>   // needed for the sort() function
 #include "G4VProcess.hh"  // needed for the degugging message of the process name
-#include "G4RunManager.hh"
-#include "G4Run.hh"
 #include "musrParameters.hh"
 #include "musrErrorMessage.hh"
 #include "musrSteppingAction.hh"
@@ -154,10 +152,6 @@ void musrScintSD::EndOfEvent(G4HCofThisEvent*) {
   //  Positron_momentum_already_stored=0;
   musrRootOutput* myRootOutput = musrRootOutput::GetRootInstance();
 
-  G4RunManager* fRunManager = G4RunManager::GetRunManager();
-  myRootOutput->SetRunID(fRunManager->GetCurrentRun()->GetRunID());
-  myRootOutput->SetEventID(fRunManager->GetCurrentEvent()->GetEventID());
-
   G4int NbHits = scintCollection->entries(); 
   
   if (myStoreOnlyEventsWithHits) {
@@ -373,8 +367,6 @@ void musrScintSD::EndOfEvent(G4HCofThisEvent*) {
 
     }
   }   //end "if (NbHits>0)"
-
-  myRootOutput->FillEvent();
 }  
 
 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......