Attenuation in iron of neutrons produced by 120Â GeV/c positive hadrons on a thick copper target

A deep penetration experiment in a thick iron shield was carried out at CERN, at the CERN-EU high-energy Field (CERF) facility. A 120 GeV/c positive hadron beam impinged on a 50 cm thick copper target located inside an irradiation cave covered by an iron shield, the thickness of which could be varied from 40 to 240 cm. Measurements of neutron fluence and ambient dose equivalent were performed with a Bonner Sphere Spectrometer and an extended-range rem counter and the results compared with Monte Carlo simulations carried out with the FLUKA code. A comparison with literature data shows an acceptable agreement. A discussion is also given on the contribution of the neutron background and of its influence on a deep penetration experiment.