diff -u -r1.10 -r1.11
--- CDFSiSensorSim.java	9 Apr 2008 14:04:06 -0000	1.10
+++ CDFSiSensorSim.java	9 Jul 2008 21:28:52 -0000	1.11
@@ -54,7 +54,7 @@

     
     // Static parameters - not intended to be user modifiable
     private static double _DEPOSITION_GRANULARITY = 0.10; // 10% of pitch or depleted thickness

-    

+    private static final double DISTANCE_ERROR_THRESHOLD = 0.001; //This is the maximum distance outside of the sensor allowed before an error is thrown. 

     
     /**
      * Creates a new instance of CDFSiSensorSim

@@ -442,8 +442,13 @@

         
 //        System.out.println("Distance from side: "+distance);
         

-        if (distance < -GeomOp3D.DISTANCE_TOLERANCE) distance = 0;
-        if (distance > thickness+GeomOp3D.DISTANCE_TOLERANCE) distance = thickness;

+        
+        if (distance < -DISTANCE_ERROR_THRESHOLD || distance > thickness + DISTANCE_ERROR_THRESHOLD){
+            throw new RuntimeException("Distance is outside of sensor by more than "+DISTANCE_ERROR_THRESHOLD+". Distance = "+distance+
+                    ". If this is an isolated event, then perhaps DISTANCE_ERROR_THRESHOLD must be increased in CDFSiSensorSim"); 
+        }
+        else if (distance < 0) distance = 0.;
+        else if (distance > thickness) distance = thickness;

 //        {
 //            throw new RuntimeException("Attempting to drift charge from outside of sensor!");
 //        }