Modeling of the primary proton beamline of the Fermilab NuMI project

Abstract

The 120 GeV primary proton beamline for the NuMI-MINOS experiment at Fermilab will transport one of the most intense high-energy beams ever constructed. In parallel operation with the Collider program, 80% of the intensity capability of the Fermilab Main Injector can be sent to NuMI. Radiation safety pertaining to residual activity, damage of equipment and irradiation of groundwater is a primary concern. A particular challenge is that this beam will be transported to and targeted in a cavern excavated in rock in an aquifer region. A model of the beamline, including transport elements and excavated enclosures, has been built in the radiation simulation program MARS. This model has been used to determine limits for allowable beam loss, and to study effects of instabilities and of various failure types. Some results obtained with this model are presented.