Spectroscopic real-time temperature diagnostic for laser-heated thin gold foils

Abstract

Target pre-heating has proven to be beneficial for laser-driven heavy-ion acceleration. As it allows to remove omnipresent carbohydrate surface contaminants, heating can affect the cutoff energy and increase the efficient acceleration of heavy ions as, e.g., required for the novel fission-fusion nuclear reaction scheme where kinetic energies of fissile species around 7 MeV/u are targeted. At the Centre for Advanced Laser Applications in Garching we use a 3W Nd:YAG cw laser to heat the (in our case gold) target foil in order to investigate the dependency of efficient gold ion acceleration on heating parameters. For real-time assessment of the surface temperature the thermal spectrum is measured with a NIR spectrometer to which Planck’s law is fitted.