Investigations of fast neutron production by high energy muon interactions on different targets

The production of fast neutrons (1 MeV-1 GeV) in high energy muon- nucleon interactions is poorly understood. Yet it is fundamental to the understanding of the background in many underground experiments. The aim of the NA55 experiment is to measure the cross-section for fast neutron production by the interaction of 190 GeV/c muons on different targets. The experiment was performed during 3 months, and a preliminary analysis, based on a few runs using graphite target in one particular distance configuration of the detector, shows how to extract the neutron time-of-flight spectra with the pulse shape discrimination. (10 refs).