Metallic particle formation by MeV proton irradiation in liquid

Ion irradiation in liquid was performed using a tandem accelerator and beam injection with a glass capillary. Nanoparticles of transition metals (Ni, Cu, Ag, Pt, and Au) were grown in the solution by reduction of the metallic ions in a process induced by proton irradiation. We could deposit the particles directly on the substrate at the irradiated position. The size of the particles was controllable by continuing the irradiation. Bimetallic Pt-Cu particles could be formed at any elemental ratio. Incorporation of oxygen into the particles was suppressed by selecting a scavenger at an appropriate concentration.