High-performance ion source generated by ultraviolet laser irradiation of Cu crystals.

Ultraviolet laser driven radiation pressure acceleration of Cu crystals is investigated by using particle-in-cell simulations. When an ultrathin Cu crystal is irradiated by a circularly polarized pulse with wavelength λ = 72 nm, waist radius w 0 = 4 λ , and normalized magnitude a 0 = 20 (energy of 85 mJ), a plasma with a lattice structure is generated first. Then, an acceleration field of 14.2 TV/cm can be induced by the radiation pressure of the ultraviolet pulse in the target, which is about one order of magnitude larger than that of optical lasers for the same a0, and the lattice structure exerts effect on the acceleration only in the vicinity of the optimal target thickness. As a result, a quasi-monoenergetic Cu ion beam of energy of 5 GeV (75 MeV/nucleon), a charge of 0.12 nC, and the emittance of 7 × 10 − 9 m rad can be produced, which implies that using ultraviolet lasers instead of optical lasers should turn down the size and emittance of ion sources by orders lower than that of optical lasers. Therefore, a high-performance ion source is produced, which may have potential applications in medical therapy and ion radiography. [ABSTRACT FROM AUTHOR]