ISABELLE shielding criteria and design

ISABELLE is a high-intensity 400-GeV proton-storage ring under construction at Brookhaven National Laboratory (BNL). The radiation-protection problems encountered in its design are in many ways similar to those at high-energy fixed-target facilities: both the laboratory personnel nearby and the public several kilometers away must be appropriately protected from high-energy neutron and muon radiation. These radiations will result from the routine operation of the accelerators, as well as from unplanned and possibly large losses of the stored beam. The radiation exposures resulting from the loss of beam already in the accelerator could be more severe than those resulting from a full year's normal operation. The design goals (mrem/yr) which have been adopted for different populations, exposure scenarios and radiation sources are outlined. We also describe the methods (hardware, shielding, access control) which will be used to achieve these goals.