Cryogenic hydrogen targets for proton beam generation with ultra-intense lasers.

The recent emergence of commercial, high repetition rate, intense lasers opens up new prospects for applications. Of particular interest is the production of energetic proton beams through the interaction of an intense laser with a hydrogen target: this beam can then be used e.g. for proton therapy (cancer treatment), or for neutron production through interaction of the proton or deuteron beam with a secondary target. If physical processes involved in the production of protons have started to receive satisfactory explanations, the reliable production of protons at high repetition rate without any debris is still an issue. In this context, SBT has developed different cryostats to generate thin ribbons of hydrogen through extrusion of solid hydrogen, and optimize and predict the conditions for extrusion. In this article, we show, how thin hydrogen ribbons are produced, and high energy proton beams are generated. A few results are given, and future plans are discussed