Systematics of thick target neutron yields for reactions of hundred GeV protons on target

Systematics of neutron energy spectra for 120 GeV protons on C, Al, Cu and W targets are presented for data measured using the time-of-flight technique, room-scattering subtraction, and experimentally determined neutron detection efficiency. The measured neutron energy spectra exhibited low-energy angular-independent and high-energy angular-dependent components, below and above about 50 MeV, respectively. The neutron yields of both components increased linearly with target thickness. We obtained neutron yields for one interaction length target and determine the normalization factors from the ratio of the target thickness to the interaction length. We observed a non-linear relationship between neutron yield and target mass number.