Production and multiplication of neutrons in lead targets induced by protons above 1 GeV

The results on neutron production in various lead targets obtained in measurements with 1–3.7 GeV proton beam by the TOF and threshold detector methods are given. It is shown that the modified Moving Source Model is a good tool for fitting of the neutron double-differential cross-section above 0.5 GeV with approximately constant temperature parameters. Analysis of available experimental data shows a saturation effect for the neutron multiplicity in the reaction Pb ( p , nx ) with the proton energy. For the extended lead target 20 diam . × 60 cm secondary nuclear interactions in the target give a large and increasing with energy contribution to the neutron yield. For this target the mean neutron multiplicity per unit of proton energy has a broad maximum in a range 1–2 GeV. The same function but for the kinetic energy of neutrons continues to grow with the beam energy due to increasing of the average energy of neutrons. This phenomenon could be used for further multiplication of neutrons in a target-blanket system.