Self-pinched lithium beam transport experiments on SABRE

Summary form only given. We are currently preparing for a self-pinched lithium beam transport experiment on the SABRE accelerator (5 MV, 35-50 kA Li/sup +/). There are three transport elements that must eventually be demonstrated: (1) efficient lithium beam generation and ballistic transport to a focus at the self-pinched transport channel entrance; (2) self-pinched transport in the channel, requiring optimized injection conditions and gas breakdown; and (3) self-pinched transport of the equilibrated beam from the channel into free space, with associated aiming and stability considerations. Recent progress in lithium beam generation has made it practical to attempt lithium self-pinched transport. In the present experiment, a hollow annular lithium beam from an applied-B extraction ion diode will be focused to small radius (r/spl les/2 cm) in a 60 cm long ballistic focus section containing argon gas at a pressure of a few Torr. The extraction diode with an appropriate magnetic field profile for uniform lithium production and focusing is being designed using diffusion ATHETA and TWOQUICK PIC code simulations. The self-pinched transport channel will contain a low pressure background gas of 10-40 mTorr argon to allow sufficient net current to confine the beam for long distance transport IPROP simulations are in progress to optimize the design of the ballistic and self-pinched transport sections. Progress on preparation of this lithium self-pinched transport experiment, including a discussion of transport system design, important gas breakdown issues, and diagnostics, will be presented.