diff --git a/src/settings.cpp b/src/settings.cpp
index b62091571..37762517b 100644
--- a/src/settings.cpp
+++ b/src/settings.cpp
@@ -459,9 +459,12 @@ void read_settings_xml()
   // If no source specified, default to isotropic point source at origin with
   // Watt spectrum
   if (model::external_sources.empty()) {
+    double T[] {0.0};
+    double p[] {1.0};
     model::external_sources.push_back(make_unique<IndependentSource>(
       UPtrSpace {new SpatialPoint({0.0, 0.0, 0.0})},
-      UPtrAngle {new Isotropic()}, UPtrDist {new Watt(0.988e6, 2.249e-6)}));
+      UPtrAngle {new Isotropic()}, UPtrDist {new Watt(0.988e6, 2.249e-6)},
+      UPtrDist {new Discrete(T, p, 1)}));
   }
 
   // Check if we want to write out source