diff --git a/compact/ce_GEM.xml b/compact/ce_GEM.xml
index 4d5cceecd41d28cc78d45d4c044213a0e5d1cf9b..afac461d4c551252d9f7d99a2dcb6e05e5c1e3d8 100644
--- a/compact/ce_GEM.xml
+++ b/compact/ce_GEM.xml
@@ -16,7 +16,7 @@
     <constant name="ce_GEM_x_pos"           value="0.0 * cm"/>
     <constant name="ce_GEM_y_pos"           value="0.0 * cm"/>
     <!--<constant name="ce_GEM_z_pos"           value="-Solenoid_length/2.0 + ce_GEM_length/2.0"/>-->
-    <constant name="ce_GEM_z_pos"           value="CrystalEndcap_z_pos - CrystalBox_z_length"/>
+    <constant name="ce_GEM_z_pos"           value="-EcalEndcapN_zmin - CrystalBox_z_length - ce_GEM_length/2.0"/>
     <constant name="ce_GEM_layer"           value="8"/>
     <constant name="ce_GEM_layer_thickness" value="1.0 * cm"/>
   </define>