Characterization of ultrashort pulse laser-produced miniature hohlraum XUV sources

Experiments at the National Ignition Facility (NIF) allow the radiative~properties of dense, high-temperature matter to be studied at previously~unreachable regimes, but are limited by cost and system availability. A~scaled down system using ultra-short laser pulses and delivering energy to a~much smaller hohlraum could be capable of reaching comparable energy~densities by depositing the energy in a significantly smaller volume before~ablation of the wall material closes the cavity. The laser is tightly~focused through the cavity and then expands to illuminate the wall with an~intensity closer to that of a long pulse laser. Experiments were performed~on a number of short-pulse Ti:sapphire tabletop laser systems.~Targets include cavities machined in bulk material using low laser powers, and~then shot in situ with a single full power pulse as well as micron scale pre-fabricated~targets. Spectral characteristics were measured using a flat-field soft X-ray spectrometer and a seven channel filtered photo cathode array.~These broadband EUV sources may allow opacity and atomic physics measurements with plasma and~radiation temperatures comparable to NIF type hohlraums, but with a~significantly higher repetition rate and in a university scale system.