The investigation of high intensity laser driven micro neutron sources for fusion materials research at high fluence

The application of fast pulse, high intensity lasers to drive low cost DT point neutron sources for fusion materials testing at high ux/uence is investigated. At present, high power bench- top lasers with intensities of 10 18 W=cm 2 are routinely employed and systems capable of10 21 W=cm 2 are becoming available. These potentially oer sucient energy density for ecient neutron production in DT targets with dimensions of around 100 m. Two dierent 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 steady state liquid cooling, the driver energy here is removed by sacricial vaporization of a small target spot. The resulting small source volumes oer the potential for a low cost, high ux source of 14 MeV neutrons at close coupled, micro (1 mm) test specimens. In particular, it is shown that a laser driven target with100 J/pulse at 100 Hz (i.e.10 kW average power) and laser irradiances in the range I 2 10 17 10 19 W m 2 =cm 2 could produce primary, uncollided neutron uxes at the test specimen in the 10 14 10 15 nc m 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.