diff --git a/src/hyperctui/__init__.py b/src/hyperctui/__init__.py
index d121e5d..74dc509 100644
--- a/src/hyperctui/__init__.py
+++ b/src/hyperctui/__init__.py
@@ -81,6 +81,8 @@ class EvaluationRegionKeys:
     id = "id of the pg horizontal line"
     name = 'name of the region'
     label_id = "id of the label naming the region"
+    from_index = "from file index"
+    to_index = "to file index"
 
 
 def load_ui(ui_filename, baseinstance):
diff --git a/src/hyperctui/autonomous_reconstruction/event_handler.py b/src/hyperctui/autonomous_reconstruction/event_handler.py
index ea72683..57bed4d 100644
--- a/src/hyperctui/autonomous_reconstruction/event_handler.py
+++ b/src/hyperctui/autonomous_reconstruction/event_handler.py
@@ -145,14 +145,21 @@ def init_autonomous_table(self):
 
         tof_regions = self.parent.tof_regions
         list_tof_region_collected = []
+        list_tof_region_index = []
         for _index in tof_regions.keys():
             if tof_regions[_index][EvaluationRegionKeys.state]:
                 _from = str(tof_regions[_index][EvaluationRegionKeys.from_value]).replace(".", "_")
                 _to = str(tof_regions[_index][EvaluationRegionKeys.to_value]).replace(".", "_")
+
+                _from_index = tof_regions[_index][EvaluationRegionKeys.from_index]
+                _to_index = tof_regions[_index][EvaluationRegionKeys.to_index]
+
                 list_tof_region_collected.append(f"from_{_from}Ang_to_{_to}Ang")
+                list_tof_region_index.append(f"from index: {_from_index} to index: {_to_index}")
 
         print(f"{formatted2_list_golden_ratio =}")
         print(f"{list_tof_region_collected =}")
+        print(f"{list_tof_region_index =}")
 
     def refresh_table_clicked(self):
         """refresh button next to the table has been clicked"""
diff --git a/src/hyperctui/autonomous_reconstruction/select_tof_regions.py b/src/hyperctui/autonomous_reconstruction/select_tof_regions.py
index 59e0e80..9b47bb0 100644
--- a/src/hyperctui/autonomous_reconstruction/select_tof_regions.py
+++ b/src/hyperctui/autonomous_reconstruction/select_tof_regions.py
@@ -12,6 +12,7 @@
 from neutronbraggedge.experiment_handler.experiment import Experiment
 
 from hyperctui.utilities.table import TableHandler
+from hyperctui.utilities.array import get_nearest_index
 from hyperctui import load_ui, EvaluationRegionKeys
 from hyperctui.session import SessionKeys
 from hyperctui.utilities.check import is_float, is_int
@@ -190,18 +191,28 @@ def save_table(self):
             _name = o_table.get_item_str_from_cell(row=_row,
                                                    column=ColumnIndex.name)
             _from = float(o_table.get_item_str_from_cell(row=_row,
-                                                       column=ColumnIndex.from_value))
+                                                         column=ColumnIndex.from_value))
             _to = float(o_table.get_item_str_from_cell(row=_row,
-                                                     column=ColumnIndex.to_value))
+                                                       column=ColumnIndex.to_value))
             _from, _to = self.sort(_from, _to)
 
+            _from_index = self.get_corresponding_index(lambda_value=_from,
+                                                       lambda_array=self.lambda_array)
+            _to_index = self.get_corresponding_index(lambda_value=_to,
+                                                     lambda_array=self.lambda_array)
+
             tof_regions[_row] = {EvaluationRegionKeys.state: _state,
                                  EvaluationRegionKeys.name: _name,
                                  EvaluationRegionKeys.from_value: float(_from),
                                  EvaluationRegionKeys.to_value: float(_to),
-                                 EvaluationRegionKeys.id: None}
+                                 EvaluationRegionKeys.id: None,
+                                 EvaluationRegionKeys.from_index: _from_index,
+                                 EvaluationRegionKeys.to_index: _to_index}
         self.parent.tof_regions = tof_regions
 
+    def get_corresponding_index(self, lambda_value=None, lambda_array=None):
+        return get_nearest_index(lambda_array, lambda_value)
+
     def check_table_content(self):
         """
         make sure 'from' and 'to' values are int
diff --git a/src/hyperctui/ui/main_application.ui b/src/hyperctui/ui/main_application.ui
index 5d17b8e..4e25e10 100644
--- a/src/hyperctui/ui/main_application.ui
+++ b/src/hyperctui/ui/main_application.ui
@@ -1378,25 +1378,6 @@
                 </property>
                </spacer>
               </item>
-              <item>
-               <widget class="QPushButton" name="pushButton">
-                <property name="minimumSize">
-                 <size>
-                  <width>50</width>
-                  <height>0</height>
-                 </size>
-                </property>
-                <property name="maximumSize">
-                 <size>
-                  <width>100</width>
-                  <height>16777215</height>
-                 </size>
-                </property>
-                <property name="text">
-                 <string>Kill process</string>
-                </property>
-               </widget>
-              </item>
              </layout>
             </item>
             <item>
@@ -2572,22 +2553,6 @@
     </hint>
    </hints>
   </connection>
-  <connection>
-   <sender>pushButton</sender>
-   <signal>clicked()</signal>
-   <receiver>MainWindow</receiver>
-   <slot>autonomous_reconstruction_stop_process_button_clicked()</slot>
-   <hints>
-    <hint type="sourcelabel">
-     <x>1026</x>
-     <y>444</y>
-    </hint>
-    <hint type="destinationlabel">
-     <x>1128</x>
-     <y>581</y>
-    </hint>
-   </hints>
-  </connection>
  </connections>
  <slots>
   <slot>step1_instrument_changed()</slot>
@@ -2636,6 +2601,5 @@
   <slot>action_step5_clicked()</slot>
   <slot>action_settings_clicked()</slot>
   <slot>refresh_list_of_obs_button_clicked()</slot>
-  <slot>autonomous_reconstruction_stop_process_button_clicked()</slot>
  </slots>
 </ui>
diff --git a/src/hyperctui/utilities/array.py b/src/hyperctui/utilities/array.py
new file mode 100644
index 0000000..8468a46
--- /dev/null
+++ b/src/hyperctui/utilities/array.py
@@ -0,0 +1,6 @@
+import numpy as np
+
+
+def get_nearest_index(array, value):
+    idx = int((np.abs(np.array(array) - value)).argmin())
+    return idx