The application of fast pulse, high intensity lasers to drive low cost DT point neutron sources for fusion materials testing at high flux/fluence is investigated. At present, high power bench-top lasers with intensities of 1018W/cm2 are routinely employed and systems capable of ⩾ 1021 W/cm2 are becoming available. These potentially offer sufficient energy density for efficient neutron production in DT targets with dimensions of around 100 μm. Two different target concepts are analysed - a hot ion, beam-target system and an exploding pusher target system - and neutron emission rates are evaluated as a function of laser and target conditions. Compared with conventional beam-target neutron sources with steadystate liquid cooling, the driver energy here is removed by sacrificial vaporization of a small target spot. The resulting small source volumes offer the potential for a low cost, high flux source of 14 MeV neutrons at close coupled, micro (⩽ 1 mm) test specimens. In particular, it is shown that a laser driven target with ∼100 J/pulse at 100 Hz (i.e. ∼10 kW average power) and laser irradiances in the range Iλ2∼1017-1019 W μm2/cm2 could produce primary, uncollided neutron fluxes at the test specimen in the 1014-1015 n cm-2 s-2 range. While focusing on the laser-plasma interaction physics and resulting neutron production, the materials science required to validate computational damage models utilizing ⩾ 100 dpa irradiation of such specimens is also examined; this may provide a multiscale predictive capability for the behaviour of engineering scale components in fusion reactor applications.
An intense DT neutron source and test conditions for fusion nuclear technology research