Design of Penetrations in Hadron Shields

Some of the problems involved in calculating the neutron flux attenuation of penetrations in hadron shields are discussed. The model used to estimate the neutron source term produced by "unpredictable" beam losses is described. The Monte Carlo program ZEUS ALB.5, which incorporates the neutron albedo data of Maerker and Muckenthaler, was modified by us and used for systematic studies of labyrinth design. Factors studied included variations in the aspect ratio (height/width) of the penetrations, placement and depth of cul-de-sacs, etc. Some of the results of our calculations of dose attenuation are given as these may be useful in the design of actual penetrations with several bends. We also give some guidelines, derived from these calculations, for designing "efficient" multileg labyrinths.