Improved tracking geom

Use a tracking geometry more in line with what the tracking working group is working on.

compact/cb_DIRC.xml

@@ -7,7 +7,7 @@
   </comment>
 
   <define>
-    <constant name="cb_DIRC_length"            value="TrackerBarrelOuter_length"/>
+    <constant name="cb_DIRC_length"            value="DIRCLength"/>
     <constant name="cb_DIRC_rmin"              value="82.00*cm"/>
     <constant name="cb_DIRC_rmax"              value="88.00*cm"/>
   </define>
@@ -24,7 +24,7 @@
   <detectors>
     <detector id="BarrelDIRC_ID" name="cb_DIRC" type="cb_DIRC" readout="DIRCHits" vis="AnlTeal">
       <dimensions rmin="cb_DIRC_rmin" rmax="cb_DIRC_rmax" length="cb_DIRC_length"/>
-      <position x="0" y="0" z="0"/>
+      <position x="0" y="0" z="DIRCOffset"/>
     </detector>
   </detectors>