diff --git a/src/est/core/types/spectrum.py b/src/est/core/types/spectrum.py
index 6e277603636a520e3d012ffccc56225fc9233c73..06e3f70ec611f3aa950a7dfb5751ec796b71dcc6 100644
--- a/src/est/core/types/spectrum.py
+++ b/src/est/core/types/spectrum.py
@@ -346,19 +346,13 @@ class Spectrum:
             self._MU_KEY: self.mu,
             self._ENERGY_KEY: self.energy,
             self._FT_KEY: self.ft.to_dict(),
-            self._NORMALIZED_MU_KEY: (
-                "None" if self.normalized_mu is None else self.normalized_mu
-            ),
-            self._NORMALIZED_ENERGY_KEY: (
-                "None" if self.normalized_energy is None else self.normalized_energy
-            ),
-            self._POST_EDGE_KEY: "None" if self.post_edge is None else self.post_edge,
-            self._NORMALIZED_BACKGROUND_KEY: (
-                "None" if self.pre_edge is None else self.pre_edge
-            ),
-            self._EDGE_KEY: "None" if self.e0 is None else self.e0,
-            self._CHI_KEY: "None" if self.chi is None else self.chi,
-            self._K_KEY: "None" if self.k is None else self.k,
+            self._NORMALIZED_MU_KEY: self.normalized_mu,
+            self._NORMALIZED_ENERGY_KEY: self.normalized_energy,
+            self._POST_EDGE_KEY: self.post_edge,
+            self._NORMALIZED_BACKGROUND_KEY: self.pre_edge,
+            self._EDGE_KEY: self.e0,
+            self._CHI_KEY: self.chi,
+            self._K_KEY: self.k,
             self._PYMCA_DICT_KEY: self.pymca_dict,
             self._LARCH_DICT_KEY: self.larch_dict,
         }