diff --git a/Detector/DetCRD/compact/CRD_common_v01/DC_Simple_v01_01.xml b/Detector/DetCRD/compact/CRD_common_v01/DC_Simple_v01_01.xml
index 437706b53400d634c49d5d1e13ec15f79416d046..23e1fe963e78e42b8c6bb2160477052412dda47a 100644
--- a/Detector/DetCRD/compact/CRD_common_v01/DC_Simple_v01_01.xml
+++ b/Detector/DetCRD/compact/CRD_common_v01/DC_Simple_v01_01.xml
@@ -18,12 +18,12 @@
     <constant name="SDT_length" value="SDT_half_length*2"/>
     <constant name="DC_length" value="DC_half_length*2"/>
 
-    <constant name="SDT_inner_chamber_radius_min" value="235*mm-DC_safe_distance"/>
+    <constant name="SDT_inner_chamber_radius_min" value="DC_inner_chamber_layer_rbegin-DC_safe_distance"/>
     <constant name="SDT_inner_chamber_radius_max" value="InnerTracker_outer_radius"/>
     <constant name="SDT_inner_chamber_length" value="DC_length"/>
 
     <constant name="SDT_outer_chamber_radius_min" value="OuterTracker_inner_radius"/>
-    <constant name="SDT_outer_chamber_radius_max" value="1715*mm+DC_safe_distance"/>
+    <constant name="SDT_outer_chamber_radius_max" value="DC_outer_chamber_radius_max"/>
     <constant name="SDT_outer_chamber_length" value="DC_length"/>
 
     <constant name="SDT_inner_chamber_layer_number" value="67"/>
@@ -31,14 +31,17 @@
     <constant name="SDT_chamber_layer_width" value="10*mm"/>
     <constant name="Epsilon" value="0*deg"/>
 
-    <constant name="SDT_inner_chamber_inner_wall_radius_min" value="234.6*mm"/>
-    <constant name="SDT_inner_chamber_inner_wall_radius_max" value="234.8*mm"/>
-    <constant name="SDT_inner_chamber_outer_wall_radius_min" value="906*mm"/>
-    <constant name="SDT_inner_chamber_outer_wall_radius_max" value="908.8*mm"/>
-    <constant name="SDT_outer_chamber_inner_wall_radius_min" value="1084*mm"/>
-    <constant name="SDT_outer_chamber_inner_wall_radius_max" value="1084.2*mm"/>
-    <constant name="SDT_outer_chamber_outer_wall_radius_min" value="1716*mm"/>
-    <constant name="SDT_outer_chamber_outer_wall_radius_max" value="1718.8*mm"/>
+    <constant name="SDT_inner_wall_thickness" value="0.2*mm"/>
+    <constant name="SDT_outer_wall_thickness" value="2.8*mm"/>
+
+    <constant name="SDT_inner_chamber_inner_wall_radius_min" value="SDT_inner_chamber_radius_min-SDT_inner_wall_thickness"/>
+    <constant name="SDT_inner_chamber_inner_wall_radius_max" value="SDT_inner_chamber_radius_min"/>
+    <constant name="SDT_inner_chamber_outer_wall_radius_min" value="SDT_inner_chamber_radius_max"/>
+    <constant name="SDT_inner_chamber_outer_wall_radius_max" value="SDT_inner_chamber_radius_max+SDT_outer_wall_thickness"/>
+    <constant name="SDT_outer_chamber_inner_wall_radius_min" value="SDT_outer_chamber_radius_min-SDT_inner_wall_thickness"/>
+    <constant name="SDT_outer_chamber_inner_wall_radius_max" value="SDT_outer_chamber_radius_min"/>
+    <constant name="SDT_outer_chamber_outer_wall_radius_min" value="SDT_outer_chamber_radius_max"/>
+    <constant name="SDT_outer_chamber_outer_wall_radius_max" value="SDT_outer_chamber_radius_max+SDT_outer_wall_thickness"/>
 
     <constant name="DC_Endcap_rmin" value="SDT_radius_min"/>
     <constant name="DC_Endcap_rmax" value="SDT_radius_max"/>
@@ -51,11 +54,22 @@
 
   </define>
 
+  <limits>
+    <limitset name="DC_limits">
+      <limit name="step_length_max" particles="*" value="0.5" unit="mm" />
+    </limitset>
+  </limits>
+
+  <regions>
+    <region name="DriftChamberRegion">
+    </region>
+  </regions>
+
   <detectors>
-    <detector id="DetID_DC" name="DriftChamber" type="DriftChamber" readout="DriftChamberHitsCollection" vis="BlueVis" sensitive="true" insideTrackingVolume="true">
+    <detector id="DetID_DC" name="DriftChamber" type="DriftChamber" readout="DriftChamberHitsCollection" vis="BlueVis" sensitive="true" insideTrackingVolume="true" limits="DC_limits">
       <envelope vis="SeeThrough">
         <shape type="BooleanShape" operation="Union" material="Air">
-          <shape type="Tube" rmin="SDT_radius_min" rmax="909*mm" dz="SDT_half_length" />
+          <shape type="Tube" rmin="SDT_radius_min" rmax="OuterTracker_inner_radius" dz="SDT_half_length" />
           <shape type="Tube" rmin="SDT_outer_chamber_inner_wall_radius_min" rmax="SDT_radius_max" dz="SDT_half_length" />
         </shape>
       </envelope>
@@ -78,7 +92,7 @@
 
   <readouts>
     <readout name="DriftChamberHitsCollection">
-      <segmentation type="GridDriftChamber" cell_size="10*mm" epsilon0="Epsilon" detector_length="DC_length" identifier_phi="cellID" DC_inner_rmin="SDT_inner_chamber_radius_min" DC_inner_rmax="SDT_inner_chamber_radius_max" DC_outer_rmin="SDT_outer_chamber_radius_min" DC_outer_rmax="SDT_outer_chamber_radius_max" layerID="layer"/>
+      <segmentation type="GridDriftChamber" cell_size="10*mm" epsilon0="Epsilon" detector_length="DC_length" identifier_phi="cellID" DC_inner_rbegin="DC_inner_chamber_layer_rbegin" DC_inner_rend="DC_inner_chamber_layer_rend" DC_outer_rbegin="DC_outer_chamber_layer_rbegin" DC_outer_rend="DC_outer_chamber_layer_rend" DC_inner_rmin="SDT_inner_chamber_radius_min" DC_inner_rmax="SDT_inner_chamber_radius_max" DC_outer_rmin="SDT_outer_chamber_radius_min" DC_outer_rmax="SDT_outer_chamber_radius_max" DC_inner_layer_number="SDT_inner_chamber_layer_number" DC_outer_layer_number="SDT_outer_chamber_layer_number" safe_distance="DC_safe_distance" layerID="layer" layer_width="SDT_chamber_layer_width"/>
 
       <id>system:8,chamber:1,layer:8,cellID:16</id>
     </readout>
diff --git a/Detector/DetCRD/compact/CRD_o1_v01/CRD_Dimensions_v01_01.xml b/Detector/DetCRD/compact/CRD_o1_v01/CRD_Dimensions_v01_01.xml
index 4291475b54acb191083bb344011b60a2397273f8..519eb0cb1df53190bf606a4f033da7c54eef511f 100644
--- a/Detector/DetCRD/compact/CRD_o1_v01/CRD_Dimensions_v01_01.xml
+++ b/Detector/DetCRD/compact/CRD_o1_v01/CRD_Dimensions_v01_01.xml
@@ -83,13 +83,21 @@
 
     <constant name="DC_Endcap_z" value="0.1*mm"/>
     <constant name="DC_half_length"  value="2225*mm" />
-    <constant name="DC_safe_distance" value="0.02*mm"/>
+    <constant name="DC_safe_distance" value="0.2*mm"/>
+    <constant name="DC_inner_chamber_layer_rbegin" value="235*mm"/>
+    <constant name="DC_inner_chamber_layer_rend" value="905*mm"/>
+    <constant name="DC_outer_chamber_layer_rbegin" value="1085*mm"/>
+    <constant name="DC_outer_chamber_layer_rend" value="1715*mm"/>
+    <constant name="DC_inner_chamber_radius_min" value="DC_inner_chamber_layer_rbegin"/>
+    <constant name="DC_inner_chamber_radius_max" value="909*mm"/>
+    <constant name="DC_outer_chamber_radius_min" value="DC_outer_chamber_layer_rbegin"/>
+    <constant name="DC_outer_chamber_radius_max" value="1716*mm"/>
     <constant name="MainTracker_half_length"  value="DC_half_length+DC_Endcap_z" />
     <constant name="InnerTracker_half_length"  value="DC_half_length" />
     <constant name="InnerTracker_inner_radius" value="234*mm"/>
-    <constant name="InnerTracker_outer_radius" value="906*mm"/>
+    <constant name="InnerTracker_outer_radius" value="DC_inner_chamber_radius_max"/>
     <constant name="OuterTracker_half_length"  value="DC_half_length"/>
-    <constant name="OuterTracker_inner_radius" value="1085*mm-DC_safe_distance"/>
+    <constant name="OuterTracker_inner_radius" value="DC_outer_chamber_radius_min-DC_safe_distance"/>
     <constant name="OuterTracker_outer_radius" value="1720*mm"/>
     
     <constant name="SIT1_inner_radius"   value="152.90*mm"/>