Los Alamos National Laboratory short pulse experiments have shown
using various target cleaning techniques such that heavy ion beams of
different charge states can be produced. Furthermore, by controlling the
thickness of light ions on the rear of the target, monoenergetic ion
pulses can be generated. The spectral shape of the accelerated particles
can be controlled to yield a range of distributions, from Maxwellian to
ones possessing a monoenergetic peak at high energy. The key lies in
understanding and utilizing target surface chemistry. Careful monitoring
and control of the surface properties and induction of reactions at
different temperatures allows well defined source layers to be formed,
which in turn lead to the desired energy spectra in the acceleration
process. Theoretical considerations provide understanding of the process
of monoenergetic ion production. In addition, numerical modeling has
identified a new acceleration mechanism, the laser break-out afterburner
that could potentially boost particle energies by up to two orders of
magnitude for the same laser parameters. This mechanism may enable
application of laser-accelerated ion beams to venues such as compact
accelerators, tumor therapy, and ion fast ignition.
