diff --git a/src/flow2supera/driver.py b/src/flow2supera/driver.py
index 47344d1..0f32a86 100644
--- a/src/flow2supera/driver.py
+++ b/src/flow2supera/driver.py
@@ -210,6 +210,7 @@ def ReadEvent(self, data, is_sim=True,verbose=False):
         
         if not is_sim:
             hits = data.hits
+            self._edeps_unassociated.reserve(len(hits))
             for i_ht, hit in enumerate(hits):
                 edep = supera.EDep()
                 edep.x = hit['x']
@@ -217,7 +218,7 @@ def ReadEvent(self, data, is_sim=True,verbose=False):
                 edep.z = hit['z']
                 edep.t = hit['t_drift']
                 edep.e = hit['E']
-                supera_event.unassociated_edeps.push_back(edep)
+                self._edeps_unassociated.push_back(edep)
             return supera_event
     
         if data.trajectories is None:
diff --git a/src/flow2supera/utils.py b/src/flow2supera/utils.py
index 9864954..3168cad 100644
--- a/src/flow2supera/utils.py
+++ b/src/flow2supera/utils.py
@@ -262,7 +262,7 @@ def run_supera(out_file='larcv.root',
         if save_log: logger['time_read'].append(time_read)
 
         t1 = time.time()
-        EventInput = driver.ReadEvent(input_data)
+        EventInput = driver.ReadEvent(input_data, is_sim=reader._is_sim)
         time_convert = time.time() - t1
         print("[run_supera] data conversion {:.3e} seconds".format(time_convert))
         if save_log: logger['time_convert'].append(time_convert)
@@ -279,7 +279,7 @@ def run_supera(out_file='larcv.root',
 
             t3 = time.time()
             tensor_hits = writer.get_data("sparse3d", "hits")
-            driver.Meta().edep2voxelset(EventInput.unassociated_edeps).fill_std_vectors(id_v, value_v)
+            driver.Meta().edep2voxelset(driver._edeps_unassociated).fill_std_vectors(id_v, value_v)
             larcv.as_event_sparse3d(tensor_hits, meta, id_v, value_v)          
 
         else: