Status of the development of the HiPER single-shot target

The High Power laser Energy Research facility (HiPER) is a European project dedicated to demonstrating the feasibility of producing energy by laser-driven inertial confinement fusion. A first design of the fast ignition cryogenic target has been established. It is composed of a thin-walled micro-shell with an inserted gold cone and filled with deuterium-tritium (DT) fuel by means of a capillary (conically guided capsule). After assembly, targets must be tight at cryogenic temperatures (16 to 19.6 K). In order to evaluate the manufacturing feasibility of a single-shot target prototype, a program has been adapted from the Laser Megajoule (LMJ) cryogenic target fabrication know-how. Target component study for HiPER concerns a hollow gold cone (25-deg half-angle and ∼25-μm thickness), a thin polymeric micro-shell (2-mm diameter and 3- to 10-μm thickness), and a silica capillary (30-μm outer diameter). First gas-tight targets at 77 K have been produced (helium gas leak rate similar to 1.4 * 10-11 Pa.m3/s). Major efforts have been focused on thin-walled micro-shells, robust gold cone fabrication, and target assembly (minimizing of the glue quantity as well as helium gas leak tests) and will be discussed in this paper. (authors)