Shielding of proton accelerators

This paper discusses some of the methods that can be employed for calculating shielding of proton accelerators, showing that a simple analytical model is often useful for a first estimate before going into complex Monte Carlo simulations. In particular what we call the Monte Carlo 'hybrid' approach, which employs source terms and attenuation length data calculated by Monte Carlo simulations under generic geometrical conditions, with a point-source line-of-sight model is discussed. Examples are given of the application of this method to the shielding calculations of two versions of the CERN SPL (2- and 3.5-GeV energy), comparing its results with Monte Carlo simulations of the full geometry.