TARGET IRRADIATED WITH I-GeV PROTONS

Comparisons with the precise theoretical description (obtained at the present time) of the integrated neutron yield from an extended uranium target and plutonium yields on fast critical assemblies are given in [3]. It is noted that accuracy of the experimental description of the first type is significantly less~ in the opinion of the authors, who talk about the insufficiency of the nuclear physics data for practical application of electronuclear production. To understand the reason for having the discrepancy, it might help to study the differential characteristics of the hadronic cascade in a target, such as the energy spectrum of the neutron flux at various points along the surface of the target~ An experimental neutron energy spectrum was obtained in [8], with ~ GeV pronon irradiation of a cylindrical lead target with diameter 200 nml~ and length 600 mm. The energy distribution of neutrons was measured on its lateral surface, at distances of 55, 145, 300, and 540 m/n from its front face (Figs. 1 and 2). The goal of this work is to study the possibility of describing these experimental results [8] on the basis of existing nuclear physics data and models based on the development of the hadron-nucleus cascade in matter. The complex program MARS-10 [9] was used as a basis, supplemented with developed neutron systematics. We have studied the characteristics of the process of particle transmission, expressed in mathematical expectations: the differential spectrum of the neutron f!ux at various points on the surface of the target, the corresponding integrated flux, and the total neutron yield from the traget. As has been shown in [i0] the inclusive scheme of the development of the cascade in matter allows one to correctly calculate the size of the increase, if, as it has been proposed, the angular and energy distributions do not depend on the total