diff --git a/DDCore/include/DD4hep/DetType.h b/DDCore/include/DD4hep/DetType.h
index fbbdac0df629bebfd3898595f97ac2589359053d..912ba8b5f1fe47e743ac2698a150ddf33f229063 100644
--- a/DDCore/include/DD4hep/DetType.h
+++ b/DDCore/include/DD4hep/DetType.h
@@ -53,7 +53,9 @@ namespace DD4hep {
       MUON	   = 1 << 13, 
       SUPPORT      = 1 << 14,
       BEAMPIPE     = 1 << 15, 
-      COIL         = 1 << 16 
+      COIL         = 1 << 16,
+      AUXILIARY    = 1 << 16 
+
    } ;
     
 
@@ -114,6 +116,8 @@ namespace DD4hep {
     if( t.is( DetType::SUPPORT      ) ) os << "SUPPORT, " ;
     if( t.is( DetType::BEAMPIPE     ) ) os << "BEAMPIPE, " ;
     if( t.is( DetType::COIL         ) ) os << "COIL, " ;
+    if( t.is( DetType::AUXILIARY    ) ) os << "AUXILIARY, " ;
+
     return os ;
   }
 
diff --git a/DDDetectors/compact/detector_types.xml b/DDDetectors/compact/detector_types.xml
index f09b9f839d6eee204929b33f0496881bbb853469..60a3d4f90ed03c0cefdf13c8289345bfbb0ac9c6 100644
--- a/DDDetectors/compact/detector_types.xml
+++ b/DDDetectors/compact/detector_types.xml
@@ -1,5 +1,4 @@
-<
-!--
+<!--
     define global constants with enums defined in 
     $DD4hepINSTALL/DDCore/include/DD4hep/DetType.h
     NB: if that file is changed this file needs to
@@ -25,7 +24,7 @@
   <constant name="DetType_SUPPORT"         value =  " 0x4000 "/>
   <constant name="DetType_BEAMPIPE"        value =  " 0x8000 "/>
   <constant name="DetType_COIL"            value =  " 0x10000 "/>
-  <!-- <constant name="DetType_bit_ 17 " value =  " 0x20000 "/> -->
+  <constant name="DetType_AUXILIARY"       value =  " 0x20000 "/>
   <!-- <constant name="DetType_bit_ 18 " value =  " 0x40000 "/> -->
   <!-- <constant name="DetType_bit_ 19 " value =  " 0x80000 "/> -->
   <!-- <constant name="DetType_bit_ 20 " value =  " 0x100000 "/> -->