refs #8614 Should fix the issue.

Though careful checks are needed. (and system tests as well)

Code/Mantid/instrument/LET_Parameters.xml

@@ -34,7 +34,10 @@
    <value val="LET_rings_123.map"/>
 </parameter>
 
-
+<!-- Parameter describes if nexus data files are written in event mode or not -->
+<parameter name="nexus_in_event_mode" type="bool">
+    <value val = "True"/>
+</parameter>
 
 
 <!-- RunNumber to use for diag instead of the input run number if none - use input run -->

Code/Mantid/scripts/Inelastic/CommonFunctions.py

@@ -69,7 +69,7 @@ def mark_as_loaded(filename):
         logger.notice("Marking %s as loaded." % filename)
         _loaded_data.append(data_name)
 
-def load_runs(runs, sum=True):
+def load_runs(runs, sum=True,event_mode = False):
     """
     Loads a list of files, summing if the required.    
     """
@@ -95,9 +95,10 @@ def load_runs(runs, sum=True):
                 return loaded
     else:
         # Try a single run
-        return load_run(runs)
+        force = False
+        return load_run(runs,force,event_mode)
 
-def load_run(run_number, force=False):
+def load_run(run_number, force=False,event_mode = False):
     """Loads run into the given workspace. 
     
     The AddSampleLog algorithm is used to add a Filename property
@@ -136,7 +137,10 @@ def load_run(run_number, force=False):
     if filename.endswith("_event.nxs"):
         LoadEventNexus(Filename=filename, OutputWorkspace=output_name) 
     elif ext.startswith(".n"):
-        LoadNexus(Filename=filename,OutputWorkspace=output_name)
+        if event_mode : 
+            LoadEventNexus(Filename=filename,OutputWorkspace=output_name,LoadMonitors='1')
+        else:
+            LoadNexus(Filename=filename,OutputWorkspace=output_name)
     elif filename.endswith("_event.dat"):
         #load the events
         LoadEventPreNexus(EventFilename=filename, OutputWorkspace=output_name)       

Code/Mantid/scripts/Inelastic/DirectEnergyConversion.py

@@ -577,12 +577,25 @@ def get_ei(self, input_ws, resultws_name, ei_guess):
             raise TypeError('Unknown option passed to get_ei "%s"' % fix_ei)
 
         self.incident_energy= ei_guess
+        monitor_ws = input_ws;
+        if type(monitor_ws) is str:
+            pws = mtd[monitor_ws]
+        else:
+            pws = monitor_ws;
+        try: 
+            nsp = pws.getSpectrum(int(self.ei_mon_spectra[0]));
+        except:
+            monitor_ws = pws.getName()+'_monitors'
+
         # Calculate the incident energy
         ei,mon1_peak,mon1_index,tzero = \
-            GetEi(InputWorkspace=input_ws, Monitor1Spec=int(self.ei_mon_spectra[0]), Monitor2Spec=int(self.ei_mon_spectra[1]), 
+            GetEi(InputWorkspace=monitor_ws, Monitor1Spec=int(self.ei_mon_spectra[0]), Monitor2Spec=int(self.ei_mon_spectra[1]), 
                   EnergyEstimate=ei_guess,FixEi=self.fix_ei)
 
+
         self.incident_energy = ei
+        AddSampleLog(Workspace=input_ws,LogName='Ei',LogText=str(ei),LogType='Number')
+
         # Adjust the TOF such that the first monitor peak is at t=0
         ChangeBinOffset(InputWorkspace=input_ws,OutputWorkspace= resultws_name,Offset= -float(str(mon1_peak)))
         mon1_det = input_ws.getDetector(mon1_index)
@@ -768,7 +781,12 @@ def load_data(self, runs,new_ws_name=None,keep_previous_ws=False):
         Load a run or list of runs. If a list of runs is given then
         they are summed into one.
         """
-        result_ws = common.load_runs(runs, sum=True)
+        event_mode = False;
+        if hasattr(self, 'nexus_in_event_mode') and self.nexus_in_event_mode:
+            event_mode = True;
+
+        sum = True
+        result_ws = common.load_runs(runs, sum,event_mode)
         if new_ws_name != None :
             if keep_previous_ws:
                 result_ws = CloneWorkspace(InputWorkspace = result_ws,OutputWorkspace = new_ws_name)