diff --git a/compact/definitions.xml b/compact/definitions.xml
index 30eeee475159617fb2f6051cd0d1174c46381772..d8fcfa5a93d81935e46bdd6fbb109f9f6da401a7 100644
--- a/compact/definitions.xml
+++ b/compact/definitions.xml
@@ -340,7 +340,7 @@
     
     <constant name="cb_VTX_rmin"   value="33.0*mm"/>
     <constant name="cb_VTX_rmax"   value="165.0*mm"/>
-    <constant name="cb_VTX_length" value="500.0*mm"/>
+    <constant name="cb_VTX_length" value="740.0*mm"/>
 
     <constant name="cb_VTX_x_pos"   value="0.0*mm"/>
     <constant name="cb_VTX_y_pos"   value="0.0*mm"/>