Approach towards quasi-monoenergetic laser ion acceleration with doped target

Morita, Toshimasa

Ion acceleration by using a laser pulse irradiating a disk target which includes hydrogen and carbon is examined using three-dimensional particle-in-cell simulations. It is shown that over 200 MeV protons can be generated by using a 620 TW, 5 W/cm laser pulse. In a polyethylene (CH) target, protons and carbon ions separate and form two layers by radiation pressure acceleration. A strong Coulomb explosion in this situation and Coulomb repulsion of each layer generates high energy protons. A doped target, low density hydrogen within a carbon disk, becomes a double layer target which is comprised of a thin and low density hydrogen disk on the surface of a high- atom layer. This then generates a quasi-monoenergetic proton beam.