diff --git a/MOT Capture Process Simulation/@MOTSimulator/computeTimeSpentInInteractionRegion.m b/MOT Capture Process Simulation/@MOTSimulator/computeTimeSpentInInteractionRegion.m
new file mode 100644
index 0000000..b7d9705
--- /dev/null
+++ b/MOT Capture Process Simulation/@MOTSimulator/computeTimeSpentInInteractionRegion.m	
@@ -0,0 +1,20 @@
+function T = computeTimeSpentInInteractionRegion(this, r)
+%     INPUT:
+%     r : N x 3 array. N is the number of time steps
+%     OUTPUT
+%     T : gives the distribution of time spent in the interaction region
+%     USAGE:
+%     T = this.computeTimeSpentInInteractionRegion(r)
+
+    T = 0;
+    NumberOfTimeSteps    = int64(this.SimulationTime/this.TimeStep);
+    for n = 1:(NumberOfTimeSteps - 1)
+        dr = Helper.calculateDistanceFromPointToLine(r(n+1, :), [0 0 0], [1 0 0]);
+        if dr < this.CoolingBeamRadius
+            A = 1;
+        else
+            A = 0;
+        end
+        T = T + A * this.TimeStep;
+    end
+end
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