Calibration of LHCf calorimeters for photon measurement by CERN SPS test beam

Energy resolution and linearity of the LHCf calorimeters for electromagnetic showers were measured at the SPS H4 beam line in 2007 using electron beams of 50-200 GeV and muon beams of 150 GeV. The absolute energy scale was determined in these data. The results that were obtained (<5% energy resolution) are well understood by using Monte Carlo simulations and are good enough for the requirements of the LHCf experiment.