diff --git a/compact/materials.xml b/compact/materials.xml
index 837b7f028d3138380804a505b5dbe1ca64ed71ab..6f7d2641b29cc0122a45df8bd09fa17dda42bb6e 100644
--- a/compact/materials.xml
+++ b/compact/materials.xml
@@ -185,6 +185,12 @@
     <composite n="1" ref="W"/>
     <composite n="4" ref="O"/>
   </material>
+	<material name="Ar10CO2">
+		<D type="density" value= "1.802e-3" unit="g / cm3"/>
+		<composite n="10" ref="Ar"/>
+		<composite n="1"  ref ="C"/>
+		<composite n="2"  ref="O"/>
+	</material>
 
   <material name="Ar10CO2">
     <D type="density" value="1.802" unit="mg / cm3"/>