Title: Materials processing with intense pulsed ion beams and masked targets,
Abstract: Intense, pulsed ion beams locally heat materials and deliver dense electronic
excitations that can induce materials modifications and phase transitions.
Materials properties can potentially be stabilized by rapid quenching. Pulsed
ion beams with (sub-) ns pulse lengths have recently become available for
materials processing. Here, we optimize mask geometries for local modification
of materials by intense ion pulses. The goal is to rapidly excite targets
volumetrically to the point where a phase transition or local lattice
reconstruction is induced followed by rapid cooling that stabilizes desired
materials properties fast enough before the target is altered or damaged by e.
g. hydrodynamic expansion. We performed HYDRA simulations that calculate peak
temperatures for a series of excitation conditions and cooling rates of silicon
targets with micro-structured masks and compare these to a simple analytical
model. The model gives scaling laws that can guide the design of targets over a
wide range of pulsed ion beam parameters.