Control of the charge and energy of the proton beams from a laser-driven double-layer target

•This is a numerical study on the double layer scheme of plasma-based laser driven ion and proton acceleration.•Found that the charge and energy of the proton beam can be controlled by the areal density of the proton layer and the target thickness.•We suggested using the SAMs technique for the fabrication of the proton-containing layer for the beam charge control.

Control of the proton beam charge and energy in a laser-driven double-layer target was numerically investigated. Generally the proton beam charge is determined by the areal density σ = nl of the second layer, while the accelerating field is governed by the substrate thickness L. From a series of one-dimensional particle-in-cell simulations over a broad range of σ and L, it was confirmed that those two control parameters do not interfere significantly, indicating the beam charge and energy can be separately controlled. We suggest self-assembly monolayers technique be used for the fabrication of the areal density of the second layer.