Effect of magnetic fields on the dose estimates due to beam halo loss in the ring collimation straight of the SNS

The collimation straight section of the SNS ring consists of three collimators with magnets (doublets and correctors) between them. It has been determined that a large fraction of the particle halo loss occurs at the primary and secondary collimators. The dose to ring components in this location has been studied in the past. In this revised dose estimate the effect of including the magnetic fields associated with the doublet located between the collimators will be made. The dose estimates are made using the MCNPX multiparticle Monte Carlo code, with an appropriate modification which allows tracking charged particles through magnetic fields. The magnetic field is pregenerated by the COSY INFINITY code. The pregenerated data is in the form of a map, which is assigned to each magnetic cell in the MCNPX calculation. The dose to selected components, and the sensitivity of its magnitude to the presence of the magnetic field will be evaluated.