The High Current Experiment (HCX) is being assembled at Lawrence
Berkeley National Laboratory as part of the U.S. program to
explore heavy ion beam transport at a scale representative of
the low-energy end of an induction linac driver for fusion energy
production. The primary mission of this experiment is to
investigate aperture fill factors acceptable for the transport
of space-charge dominated heavy ion beams at high space-charge
intensity (line-charge density ∼ 0.2 μC/m) over
long pulse durations (>4 μs). This machine will test
transport issues at a driver-relevant scale resulting from
nonlinear space-charge effects and collective modes, beam centroid
alignment and beam steering, matching, image charges, halo,
lost-particle induced electron effects, and longitudinal bunch
control. We present the first experimental results carried out
with the coasting K+ ion beam transported through
the first 10 electrostatic transport quadrupoles and associated
diagnostics. Later phases of the experiment will include more
electrostatic lattice periods to allow more sensitive tests
of emittance growth, and also magnetic quadrupoles to explore
similar issues in magnetic channels with a full driver scale
beam.
The high current experiment: First results