diff --git a/compact/definitions.xml b/compact/definitions.xml
index 3ee957384be105e5139b3a8ff3729494da606b8b..31aedf766776c87e1c7970dae0b8e99c9033fe47 100644
--- a/compact/definitions.xml
+++ b/compact/definitions.xml
@@ -440,7 +440,7 @@
     <constant name="ffi_ZDC_rotateZ_angle" value="0.0 * rad"/>-->
 
     <comment> Global parameters </comment>
-    <constant name="ffi_ZDC_width"             value="60.0 * cm"/>
+    <constant name="ffi_ZDC_width"             value="50.0 * cm"/>
     <constant name="ffi_ZDC_thickness"         value="250.0 * cm"/>
     <constant name="ffi_ZDC_ECAL_thickness"    value="30.0 * cm"/>
     <constant name="ffi_ZDC_ECAL_inner_radius" value="0.0 * cm"/>