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 71037c5c19390d0ffc0519e7f54e519d7f915986..cb346b082a29872267f46861cc7aeb3073ad6ca3 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
@@ -29,10 +29,14 @@
     <constant name="SDT_chamber_layer_width" value="10*mm"/>
     <constant name="Epsilon" value="0*deg"/>
 
-    <constant name="SDT_inner_wall_radius_min" value="234.8*mm"/>
-    <constant name="SDT_inner_wall_radius_max" value="235*mm"/>
-    <constant name="SDT_outer_wall_radius_min" value="1715*mm"/>
-    <constant name="SDT_outer_wall_radius_max" value="1717.8*mm"/>
+    <constant name="SDT_inner_chamber_inner_wall_radius_min" value="234.8*mm"/>
+    <constant name="SDT_inner_chamber_inner_wall_radius_max" value="235*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="1084.8*mm"/>
+    <constant name="SDT_outer_chamber_inner_wall_radius_max" value="1085*mm"/>
+    <constant name="SDT_outer_chamber_outer_wall_radius_min" value="1715*mm"/>
+    <constant name="SDT_outer_chamber_outer_wall_radius_max" value="1717.8*mm"/>
 
   </define>
 
@@ -40,8 +44,8 @@
     <detector id="DetID_DC" name="DriftChamber" type="DriftChamber" readout="DriftChamberHitsCollection" vis="BlueVis" sensitive="true" insideTrackingVolume="true">
       <envelope vis="SeeThrough">
         <shape type="BooleanShape" operation="Union" material="Air">
-	  <shape type="Tube" rmin="SDT_radius_min" rmax="SDT_inner_chamber_radius_max" dz="SDT_half_length" />
-          <shape type="Tube" rmin="SDT_outer_chamber_radius_min" rmax="SDT_radius_max" dz="SDT_half_length" />
+	  <shape type="Tube" rmin="SDT_radius_min" rmax="909*mm" dz="SDT_half_length" />
+          <shape type="Tube" rmin="1084.8*mm" rmax="SDT_radius_max" dz="SDT_half_length" />
         </shape>
       </envelope>
 
diff --git a/Detector/DetCRD/compact/CRD_common_v01/materials.xml b/Detector/DetCRD/compact/CRD_common_v01/materials.xml
index 74b3f3fa8dca29cc34b251fc38fc82d09884af1c..c9f7edf444b55e0cc7e766b4c87892bb081b5d28 100644
--- a/Detector/DetCRD/compact/CRD_common_v01/materials.xml
+++ b/Detector/DetCRD/compact/CRD_common_v01/materials.xml
@@ -562,4 +562,12 @@
       <fraction n="0.671054" ref="Bi" />
     </material>
 
+    <!-- Driftchamber: material for the drift chamber -->
+   <material name="GasHe_90Isob_10">
+     <D value="0.0003983999999999999" unit="g/cm3" />
+     <fraction n="0.3826351004462046" ref="He"/>
+     <fraction n="0.011371937371285891"   ref="H" />
+     <fraction n="0.6059929621825095" ref="C" />
+   </material>
+
   </materials>
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 64a9a153d6b15708ec9b17406842020637312e61..d7c15e97cfa2c49240cebbe6a1fa0196ae0ff2b3 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
@@ -84,7 +84,7 @@
     <constant name="MainTracker_half_length"  value="2225*mm" />
     <constant name="InnerTracker_half_length"  value="MainTracker_half_length" />
     <constant name="InnerTracker_inner_radius" value="234*mm"/>
-    <constant name="InnerTracker_outer_radius" value="909*mm"/>
+    <constant name="InnerTracker_outer_radius" value="906*mm"/>
     <constant name="OuterTracker_half_length"  value="MainTracker_half_length"/>
     <constant name="OuterTracker_inner_radius" value="1085*mm"/>
     <constant name="OuterTracker_outer_radius" value="1720*mm"/>