diff --git a/src/main/java/inr/numass/trapping/Simulator.java b/src/main/java/inr/numass/trapping/Simulator.java
index 0ad8c25..ad8d987 100644
--- a/src/main/java/inr/numass/trapping/Simulator.java
+++ b/src/main/java/inr/numass/trapping/Simulator.java
@@ -149,7 +149,7 @@ public class Simulator {
             double deltaZ = deltaL * cos(pos.theta); // direction already included in cos(theta)
             double z0 = pos.z;
             pos.addZ(deltaZ);
-            pos.l += abs(pos.z - z0) / cos(pos.theta);
+            pos.l += deltaL;
 
 //            //if we are crossing source boundary, check for end condition
 //            while (abs(deltaZ + pos.z) > SOURCE_LENGTH / 2d && !pos.isFinished()) {
diff --git a/src/main/java/inr/numass/trapping/Trapping.java b/src/main/java/inr/numass/trapping/Trapping.java
index 139ef92..dd357bf 100644
--- a/src/main/java/inr/numass/trapping/Trapping.java
+++ b/src/main/java/inr/numass/trapping/Trapping.java
@@ -15,8 +15,8 @@ public class Trapping {
         Instant startTime = Instant.now();
         System.out.printf("Starting at %s%n%n", startTime.toString());
         new SimulationManager()
-                .withParameters(0.6, 3.7, 4.84, 18000d, 4000)
-                .withOutputFile("D:\\Work\\Numass\\trapping\\trap 18, pinch 100A.out")
+                .withParameters(0.6, 3.7, 4.84, 14000d, 4000)
+                .withOutputFile("D:\\Work\\Numass\\trapping\\trap 14, pinch 100A.out")
 //                .withFieldMap(z, b)
 //                .withDensity(5e20)
                 .simulateAll((int) 1e6);