diff -u -r1.12 -r1.13
--- SiSensor.java	7 Aug 2007 18:11:40 -0000	1.12
+++ SiSensor.java	28 Aug 2007 22:08:22 -0000	1.13
@@ -9,10 +9,10 @@

  * Open. You can then make changes to the template in the Source Editor.
  */
 

+import hep.physics.matrix.BasicMatrix;

 import hep.physics.vec.BasicHep3Vector;
 import hep.physics.vec.Hep3Vector;
 import hep.physics.vec.VecOp;

-import hep.physics.matrix.BasicMatrix;

 
 import java.util.EnumMap;
 import java.util.List;

@@ -20,12 +20,13 @@

 
 import org.lcsim.detector.DetectorElement;
 import org.lcsim.detector.IDetectorElement;

-import org.lcsim.detector.Rotation3D;

 import org.lcsim.detector.converter.compact.DeDetector;
 import org.lcsim.detector.converter.compact.DeSubdetector;
 import org.lcsim.detector.identifier.IExpandedIdentifier;
 import org.lcsim.detector.identifier.IIdentifier;
 import org.lcsim.detector.identifier.IIdentifierHelper;

+import org.lcsim.detector.identifier.IIdentifierDictionary.FieldNotFoundException;
+import org.lcsim.detector.identifier.IIdentifierDictionary.InvalidIndexException;

 import org.lcsim.detector.solids.Box;
 
 /**

@@ -320,11 +321,18 @@

      */
     public IIdentifier makeStripId( int stripNumber, int sideNumber )
     {

-        IIdentifierHelper helper = getIdentifierHelper();
-        IExpandedIdentifier id = helper.unpack( getIdentifier(), 0, helper.getIdentifierDictionary().getFieldIndex("side") - 1);
-        id.addValue(sideNumber);
-        id.addValue(stripNumber);
-        return helper.pack( id );

+    	try {
+    		IIdentifierHelper helper = getIdentifierHelper();
+    		IExpandedIdentifier id = null;
+    		helper.unpack( getIdentifier(), 0, helper.getIdentifierDictionary().getFieldIndex("side") - 1);
+    		id.addValue(sideNumber);
+    		id.addValue(stripNumber);    	
+    		return helper.pack( id );
+    	}
+    	catch (Exception x)
+    	{
+    		throw new RuntimeException(x);
+    	}

     }
     
 }