diff --git a/GUI/Models/SphericalDetectorItem.h b/GUI/Models/SphericalDetectorItem.h
index 9cf15a266dc96244f1d73481ddb55ba179bd49da..69a0645bf4147fc03600e87be46acd37dacfe6ac 100644
--- a/GUI/Models/SphericalDetectorItem.h
+++ b/GUI/Models/SphericalDetectorItem.h
@@ -22,9 +22,9 @@ class BasicAxisItem;
 class BA_CORE_API_ SphericalDetectorItem : public DetectorItem {
 private:
     static const QString P_PHI_AXIS;
+    static const QString P_ALPHA_AXIS;
 
 public:
-    static const QString P_ALPHA_AXIS;
     SphericalDetectorItem();
 
     int xSize() const override;