DOWNSTREAM SYSTEM FOR THE SECOND AXIS OF THE DARHT FACILITY*

This paper presents the physics design of the DARHT-II downstream system, which consists of a diagnostic beam stop, a fast, high-precision kicker system and the x-ray converter target assembly. The beamline configuration, the transverse resistive wall instability and the ion hose instability modelling are presented. We also discuss elimination of spot size dilution during kicker switching and implementation of the foil-barrier scheme to minimize the backstreaming ion focusing effects. Finally, we present the target converters configuration, and the simulated DARHT-II x-ray spot sizes and doses. Some experimental results, which support the physics design, will be also presented.