diff --git a/inst/cta/include/GCTACubeSourceDiffuse.hpp b/inst/cta/include/GCTACubeSourceDiffuse.hpp
index d6f2896..1c745fd 100644
--- a/inst/cta/include/GCTACubeSourceDiffuse.hpp
+++ b/inst/cta/include/GCTACubeSourceDiffuse.hpp
@@ -83,7 +83,7 @@ public:
                const GSkyDir&          srcDir,
                const GEnergy&          srcEng,
                const GTime&            srcTime) const;
-    GNodeArray nodes(void) const;
+    const GNodeArray& nodes(void) const;
 
 protected:
     // Protected methods
@@ -147,7 +147,7 @@ double GCTACubeSourceDiffuse::irf(const int& pixel, const int& iebin) const
  * Returns node array of energy values
  ***************************************************************************/
 inline
-GNodeArray GCTACubeSourceDiffuse::nodes(void) const
+const GNodeArray& GCTACubeSourceDiffuse::nodes(void) const
 {
     return (m_logE);
 }
diff --git a/inst/cta/src/GCTAResponseCube.cpp b/inst/cta/src/GCTAResponseCube.cpp
index 24f5910..927a644 100644
--- a/inst/cta/src/GCTAResponseCube.cpp
+++ b/inst/cta/src/GCTAResponseCube.cpp
@@ -1460,7 +1460,7 @@ double GCTAResponseCube::irf_diffuse(const GEvent&       event,
     if (use_edisp()) {
 
 		// Get array of log10TeV energies of cached diffuse model
-		GNodeArray logE = cache->nodes();
+		const GNodeArray& logE = cache->nodes();
 
 		// Get true energy
 		GEnergy srcEng = source.energy();