Analysis of NRL wire-guided ion beam transport experiments

Summary form only given. A series of WGT (wire-guided transport) experiments has been fielded on the Gamble II accelerator at NRL (US Naval Research Laboratory). A pinch reflex ion diode focused a ~100-kA, ~1-MeV proton beam onto the 2.54-cm-diameter entrance aperture of a large-radius, 1-m-long transport tube. A thin copper wire positioned along the axis of the transport tube carried currents ranging up to 28 kA, thereby providing the beam-confining azimuthal magnetic field. The beam diagnostics used were a large-radius witness plate at the downstream end of the transport tube to determine the beam radius. Teflon targets positioned at various locations in the path of the beam to measure transport efficiency and time-of-flight effects using the ¹⁹F(p,αγ)¹⁶O reaction, and a shadowbox positioned at the downstream end of the transport tube to reconstruct the velocity-space distribution of the beam. The results of the three beam diagnostics were in agreement with ion orbit analyses. In particular, an analytic description of the velocity-space distribution of the beam predicted quite accurately the results of the shadowbox diagnostic