Energy calibration of the NaI(Tl) calorimeter of the SND detector using   $e^+e^- \to e^+e^-$ events
  Calibration of the three layer NaI(Tl) spherical calorimeter of the SND detector using electron -- positron scattering events is described. Energy resolution of $5 % (FWHM/2.36)$ for 500 MeV photons was achieved. 
M.N.Achasov, D.A.Bukin, T.V.Dimova, V.P.Druzhinin, V.B.Golubev,   V.N.Ivanchenko, A.A.Korol