In many applications involving intense beams, it is imperative to be able to limit the non-equilibrium fraction of the beam that may reside far from of the core of the distribution known as the beam halo. This aspect of the beam propagation has been notoriously difficult to predict, however recent progress has been made with the development of the so-called particle-core model. Since no direct verification of this model had been undertaken to date, we have carried out a precision experiment to measure halo generation associated with the transport of an intense proton beam through a linear transport channel. The LEDA RFQ was used to inject a 6.7 MeV 10-100 mA beam into a 52-quadrupole channel. Four matching quads at the input of this transport line were used to generate specific mismatch oscillations and the resulting beam profiles were measured at downstream locations over a very wide dynamic range. The results of these experiments tend to support the particle-core model and the significance of controlling mismatch oscillations in minimizing beam halo. However, some anomalous behavior has been observed which has not yet been explained by existing models. An overview of the halo generation process will be given followed by a detailed description of the experimental results


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For more information, please contact Dr. Alex Bogacz, Chair of CASA Seminar Committee