diff --git a/src/gui/DamarisGUI.py b/src/gui/DamarisGUI.py
index f947ed3..282b9ae 100644
--- a/src/gui/DamarisGUI.py
+++ b/src/gui/DamarisGUI.py
@@ -197,6 +197,9 @@ class DamarisGUI:
         # lock file to prevent other DAMARIS to start immediatly
         self.lockfile = LockFile()  # = os.path.expanduser("~/.damaris.lock")
         self.id = None
+        
+        #to stop queued experiments
+        self.stop_experiment_flag = threading.Event()
 
         exp_script = u""
         if exp_script_filename is not None and exp_script_filename != "":
@@ -454,10 +457,13 @@ class DamarisGUI:
             self.log.textbuffer.create_mark( "lastdumped", self.log.textbuffer.get_end_iter( ), left_gravity=True )
 
         loop_run=0
-        interval = 2
+        #user shorter interval because this blocks user events from the GUI
+        interval = 0.1
+        self.stop_experiment_flag.clear()
+        
         self.id = self.lockfile.add_experiment()
-        while not self.lockfile.am_i_next():
-            time.sleep(interval)
+        while not self.lockfile.am_i_next() and not self.stop_experiment_flag.isSet():
+            self.stop_experiment_flag.wait(interval)
             while gtk.events_pending():
                 gtk.main_iteration(False)
             if loop_run > 1:
@@ -937,6 +943,7 @@ class DamarisGUI:
 
     def stop_experiment( self, widget, data=None ):
         if self.state in [ DamarisGUI.Run_State, DamarisGUI.Pause_State ]:
+            self.stop_experiment_flag.set()
             if self.si is None:
                 return
             still_running = filter( None, [ self.si.exp_handling, self.si.res_handling, self.si.back_driver ] )