Modeling and Measuring the Effect of Mismatched Beam Transport on Halo Formation in a High-Intensity LINAC

Ongoing studies at the Spallation Neutron Source (SNS) Beam Test Facility (BTF) seek to characterize halo formation in the early stages of a high-power linac with specific focus on determining the contribution from mismatched beam transport and to replicate halo measurements using well-benchmarked particle-in-cell simulations. The BTF is a 2.5 MeV, 10- meter test beamline equipped with advanced phase space diagnostics allowing detailed characterization of beam distributions. This talk details recent advances in improved transport of mismatched cases in the BTF, direct measurements of 2D phase space projections with 6 orders of magnitude in dynamic range, and comparisons of predictions from the PyORBIT code to measured distributions.