  The robustness of a structured collimation device is discussed for an
intense-laser-produced ion beam. In this paper the ion beam collimation is
realized by the solid structured collimation device, which produces the
transverse electric field; the electric field contributes to reduce the ion
beam transverse velocity and collimate the ion beam. Our 2.5 dimensional
particle-in cell simulations demonstrate that the collimation device is rather
robust against the changes in the laser parameters and the collimation target
sizes. The intense short-pulse lasers are now available, and are used to
generate an ion beam. The issues in the laser ion acceleration include an ion
beam collimation, ion energy spectrum control, ion production efficiency, ion
energy control, ion beam bunching, etc. The laser-produced ion beam tends to
expand in the transverse and longitudinal directions during the ion beam
propagation. The ion beam collimation is focused in this paper.
