The performance for the TeV photon measurement of the LHCf upgraded detector using Gd2SiO5 (GSO) scintillators

The Large Hadron Collider forward (LHCf) experiment measures the forward particle production at the LHC to verify hadronic interaction models used in air shower experiments. We have upgraded very small sampling and imaging calorimeters using GSO scintillators to measure the most energetic particles generated in s=13 TeV p-p collisions at the zero-degree region of the LHC. Upgraded detectors were calibrated at the SPS North area facility in CERN and it was confirmed that the detector can measure electro-magnetic showers with energy resolution of 3% and position resolution of better than 123 ?m for 100 GeV electrons. The operation of LHCf in 13 TeV p-p collisions has been successfully completed with integrated luminosity of 5 nb-1. Reconstructed ?0 peak with the mass resolution of 3.7% and stability less than 1% during the operation implies that our measurement was stable enough in the high irradiation condition. © 2016 Elsevier B.V.