The hadron calorimeter of EAS-TOP: operation, calibration and resolution

We describe and discuss the operation, calibration and stability of the EAS-TOP calorimeter (Campo Imperatore, National Gran Sasso Laboratories), a large area hadron and muon detector devoted to cosmic-ray physics. It consists of iron slabs (for a total thickness of 818 g cm(-2)) and Iarocci tubes as sensitive layers, operating in the streamer mode and the "quasi proportional" regime. Using a model describing the operation of the "quasi proportional" chambers, we derive a calibration curve in the energy range 50-5000 GeV, whose reliability has been indirectly checked through on-site measurements, by means of an accelerator beam run (up to similar or equal to 600-700 GeV) and by comparing the model predictions on hadron shower transition curves with the data. (C) 1999 Elsevier Science B.V. All rights reserved.