The Performance of LHCf Detector

In cosmic ray physics, the uncertainty of the hadron interaction model causes systematic errors of air shower simulations in high-energy region. To solve the problem, the LHCf experiment measures energies and transverse momenta of neutral particles emitted in the forward region of 14TeV p-p collision at CERN LHC. Two LHCf detectors, consisting of sampling and imaging calorimeters, are installed at zero degree collision angle at +/- 140m from the interaction point 1 (IP1). The energy resolution is confirmed as to be <5% and the position resolution <0.2mm for gamma-rays with energies from 100GeV to 200GeV by test beam results at the CERN SPS. Use of the Front Counter reduces the beam-gas background by a factor 50.