Spallation neutron production in proton induced reactions on Al, Fe, Zr, W, Pb and Th targets at 1.2 GeV and on Fe and Pb at 0.8, and 1.6 GeV measured at the SATURNE accelerator in Saclay is reported. The experimental double-differential cross-sections are compared with calculations performed with different intra-nuclear cascade models implemented in high energy transport codes. The broad angular coverage also allowed the determination of average neutron multiplicities above 2 MeV. Deficiencies in some of the models commonly used for applications are pointed out.

Spallation neutron production in proton induced reactions on Pb targets at 0.8, 1.2, and 1.6 GeV has been measured at the SATURNE accelerator. Double-differential cross sections were obtained over a broad angular range from which averaged neutron multiplicities per reaction were inferred for energies above 2 MeV. The results are compared with calculations performed with a high energy transport code including two different intranuclear cascade (INC) models: it is shown that the Cugnon INC model gives a better agreement with the data than the Bertini one, mainly because of improved nucleonnucleon cross sections and Pauli blocking treatment. [S0031-9007 (99)09196-6] PACS numbers: 25.40.Sc, 24.10.Lx, 29.25.DzSpallation reactions can be used to produce high neutron fluxes by bombarding a thick heavy target with a high intensity intermediate energy proton beam. Interest in spallation reactions has recently been renewed because of the importance of intense neutron sources for various applications, such as spallation neutron sources for condensed matter and material physics [1-3], tritium production [4,5], accelerator-driven subcritical reactors for nuclear waste transmutation [6,7], or energy production [8]. Numerical calculation codes are available to design spallation sources. However, physics models used in these codes to describe elementary nuclear reactions above 20 MeV still suffer from large uncertainties. For instance, in [9], model predictions concerning neutron production double-differential cross sections were found to show big discrepancies between different codes. It was concluded that additional data were necessary, especially above 0.8 GeV, in order to improve and validate the models. Furthermore, neutron energy and angular distributions data are important for a correct simulation of the propagation of particles inside a spallation target and the geometrical distribution of the outgoing neutron flux.An extensive program has been conducted at the Laboratoire National Saturne to measure energy and angular distributions of neutrons produced by protons and deuterons with energies from 0.8 to 1.6 GeV on various thin and thick targets. In this Letter, we report on the measurement of double-differential cross sections obtained, at angles varying from 0 ± to 160 ± , with 0.8, 1.2, and 1.6 GeV proton beams on a 2-cm-thick Pb target.Neutron energy spectra were measured by two complementary experimental techniques, described in detail in [10,11], in a new experimental area [12].Low energy neutrons ͑E n # 400 MeV͒ were measured by time of flight between the incident proton, tagged by a plastic scintillator, and a neutron sensitive NE213 liquid scintillator [10]. Up to ten angles could be explored simultaneously using several neutron detectors. Six of them (cells of the multidetector DEMON [13]) were used between 4 and 400 MeV. The other four (called DENSE) allowed energy measurements with a reasonable error from 2 to 14 MeV. A pulse shape analysis was used for neutron-gamma discrimination. The energy resolution assoc...

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Measured angular and energetic distributions of neutrons obtained by bombarding Be, C, and U thick targets with 2 H at 17, 20, and 28 MeV incident energies are reported. The data were obtained using the time-of-flight method. The energetic distributions of neutrons were determined at 0 ± , 5 ± , 10 ± , and 20 ± . The data are compared with a modelization based on stripping formalism extended for thick targets.[S1098-4402(99)00029-4] PACS numbers: 29.25.Dz, 25.85.Ec

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