Minor fix SynchrotronRadiation

tracking/element.py

@@ -135,7 +135,7 @@ class SynchrotronRadiation(Element):
         if (self.switch[2] == True):
             rand = np.random.normal(size=len(bunch))
             bunch["yp"] = ((1 - 2*self.ring.T0/self.ring.tau[1])*bunch["yp"] +
-                 2*self.ring.sigma()[1]*(self.ring.T0/self.ring.tau[1])**0.5*rand)
+                 2*self.ring.sigma()[3]*(self.ring.T0/self.ring.tau[1])**0.5*rand)
         
 class TransverseMap(Element):
     """