On-line Diagnoses of High Current-Density Beams

Los Alamos National Laboratory has proposed several cw-proton-beam facilities for production of tritium or transmutation of nuclear waste with beam-current densities of 8 mA/mm2. The primary beam-diagnostics-instrumentation requirement for these facilities is provision of sufficient beam information to understand and minimize beam-loss. To accomplish this task, the beam-diagnostics instrumentation must measure beam parameters such as centroids and profiles, total integrated current, and particle loss. Noninterceptive techniques must be used for these measurements because the high-intensity cw beam will destroy any interceptive diagnostic device. Transverse and longitudinal centroid measurements have been developed for bunched beams by measuring and processing image currents on the accelerator walls. Transverse beam-profile measurement-techniques have also been developed using the interaction of the particle beam with the background gases near the beam region, This paper will discuss these on-line noninterceptive diagnostic techniques. 1