diff --git a/Detector/DetEcalMatrix/compact/det.xml b/Detector/DetEcalMatrix/compact/det.xml
index fb39af73d2267cf83788045fd3da3be13fc676e3..bb4f486360a1c5bee3176f9ca2214653ddda0cf7 100644
--- a/Detector/DetEcalMatrix/compact/det.xml
+++ b/Detector/DetEcalMatrix/compact/det.xml
@@ -39,7 +39,11 @@
   
   <readouts>
     <readout name="CaloHitsCollection">
-      <id>system:8</id>
+      <segmentation type="CartesianGridXYZ" 
+                    grid_size_x="1*cm" 
+                    grid_size_y="1*cm" 
+                    grid_size_z="1*cm"/>
+      <id>system:8,x:32:-6,y:-6,z:-6</id>
     </readout>
   </readouts>