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

The application of fast pulse, high intensity lasers to drive low cost DT p oint neutron sources for fusion materials testing at high flux/fluence is i nvestigated. At present, high power benchtop lasers with intensities of 10( 18) W/cm(2) are routinely employed and systems capable of greater than or e qual to 10(21) W/cm(2) are becoming available. These potentially offer suff icient energy density for efficient neutron production in DT targets with d imensions of around 100 mu m. Two different target concepts are analysed - a hot ion, beam-target system and an exploding pusher target system - and n eutron emission rates are evaluated as a function of laser and target condi tions. Compared with conventional beam-target neutron sources with steady s tate liquid cooling, the driver energy here is removed by sacrificial vapor ization of a small target spot. The resulting small source volumes offer th e potential for a low cost, high flux source of 14 MeV neutrons at close co upled, micro (less than or equal to 1 mm) test specimens. In particular, it is shown that a laser driven target with similar to 100 J/pulse at 100 Hz (i.e. similar to 10 kW average power) and laser irradiances in the range I lambda(2) similar to 10(17) - 10(19) W mu m(2)/cm(2) could produce primary, uncollided neutron fluxes at the test specimen in the 10(14)-10(15) n cm(- 2) s(-2) range. While focusing on the laser-plasma interaction physics and resulting neutron production, the materials science required to validate co mputational damage models utilizing greater than or equal to 100 dpa irradi ation of such specimens is also examined; this may provide a multiscale pre dictive capability for the behaviour of engineering scale components in fus ion reactor applications.