diff --git a/tracking/element.py b/tracking/element.py
index 519190eed15bc2418aed71e4474255e07ad85d47..0ef071c4bbde1c90c9be9c9727277017454af4da 100644
--- a/tracking/element.py
+++ b/tracking/element.py
@@ -129,15 +129,15 @@ class SynchrotronRadiation(Element):
             
         if (self.switch[1] == True):
             rand = np.random.normal(size=(len(bunch),2))
-            bunch["x"] += self.ring.sigma[0]*(2*self.ring.T0/self.ring.tau[0])**0.5*rand[:,0]
+            bunch["x"] += self.ring.sigma()[0]*(2*self.ring.T0/self.ring.tau[0])**0.5*rand[:,0]
             bunch["xp"] = (1 + bunch["delta"])/(1 + bunch["delta"] + bunch.energy_change)*bunch["xp"]
-            bunch["xp"] += self.ring.sigma[1]*(2*self.ring.T0/self.ring.tau[0])**0.5*rand[:,1]
+            bunch["xp"] += self.ring.sigma()[1]*(2*self.ring.T0/self.ring.tau[0])**0.5*rand[:,1]
         
         if (self.switch[2] == True):
             rand = np.random.normal(size=(len(bunch),2))
-            bunch["y"] += self.ring.sigma[2]*(2*self.ring.T0/self.ring.tau[1])**0.5*rand[:,0]
+            bunch["y"] += self.ring.sigma()[2]*(2*self.ring.T0/self.ring.tau[1])**0.5*rand[:,0]
             bunch["yp"] = (1 + bunch["delta"])/(1 + bunch["delta"] + bunch.energy_change)*bunch["yp"]
-            bunch["yp"] += self.ring.sigma[3]*(2*self.ring.T0/self.ring.tau[1])**0.5*rand[:,1]
+            bunch["yp"] += self.ring.sigma()[3]*(2*self.ring.T0/self.ring.tau[1])**0.5*rand[:,1]
         
         # Reset energy change to 0 for next turn
         bunch.energy_change = 0