Translates upstream by 50cm

Inserts the shift as a constant

Adds vacuum material

passive/T0Counter_v21a.gdml

@@ -2,11 +2,13 @@
 <gdml xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="http://service-spi.web.cern.ch/service-spi/app/releases/GDML/schema/gdml.xsd">
 
 <define>
-<position name="origin" unit="m" x="0" y="0" z="0" />
-<position name="up_cr" unit="m" x="0.0" y="0.0" z="-0.000040025" />
-<position name="down_cr" unit="m" x="0.0" y="0.0" z="0.000040025" />
-<position name="up_au" unit="m" x="0.0" y="0.0" z="-0.000040125" />
-<position name="down_au" unit="m" x="0.0" y="0.0" z="0.000040125" />
+<constant name="shift" value="-500"/>
+
+<position name="origin" unit="mm" x="0" y="0" z="shift" />
+<position name="up_cr" unit="mm" x="0.0" y="0.0" z="shift-0.040025" />
+<position name="down_cr" unit="mm" x="0.0" y="0.0" z="shift+0.040025" />
+<position name="up_au" unit="mm" x="0.0" y="0.0" z="shift-0.040125" />
+<position name="down_au" unit="mm" x="0.0" y="0.0" z="shift+0.040125" />
 </define>
 
 <materials>
@@ -16,6 +18,11 @@
 <element name="chromium"   formula="Cr"  Z="24">   <atom value="51.9961"/>  </element>
 <element name="gold"       formula="Au"  Z="79">   <atom value="196.97"/>   </element>
 
+<material formula=" " name="Vacuum">
+<D value="1.e-25" unit="g/cm3" />
+<fraction n="1.0" ref="videRef" />
+</material>
+
 <material name="Gold" state="solid">
 <D value="19.32" unit="g/cm3"/>
 <fraction n="1." ref="gold"/>
@@ -60,7 +67,7 @@
 <volume name="detector" >
 <materialref ref="Vacuum" />
 <solidref ref="T0Counter" />
-<positionref ref="origin" />   	
+<positionref ref="origin" />
 <physvol>
 <volumeref ref="vol_Diamond"/>
 <positionref ref="origin" />