diff --git a/tests/test_void/materials.xml b/tests/test_void/materials.xml
index 8ac0eb753..b8f993824 100644
--- a/tests/test_void/materials.xml
+++ b/tests/test_void/materials.xml
@@ -41,7 +41,7 @@
     <nuclide name="Fe-56" ao="4.6739e-05" />
     <nuclide name="Fe-57" ao="1.0794e-06" />
     <nuclide name="Fe-58" ao="1.4365e-07" />
-    <sab name="be" xs="71t" />
+    <sab name="Be" xs="71t" />
   </material>
 
   <!-- Steel Diaphragm and Steel Shaft -->