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.