Energetic neutron beams generated from femtosecond laser plasma interactions

Experiments at the HERCULES laser facility have produced directional neutron beams with energies up to 16.8(+/- 0.3) MeV using (2)(1)d(d, n)(2)He-3; Li-7(3)(p, n)(4)Be-7; and Li-7(3)(d, n)(4)Be-8 reactions. Efficient Li-7(3)(d, n)(4)Be-8 reactions required the selective acceleration of deuterons through the introduction of a deuterated plastic or cryogenically frozen D2O layer on the surface of a thin film target. The measured neutron yield was <= 1.0 (+/- 0.5) x 10(7) neutrons/sr with a flux 6.2(+/- 3.7) times higher in the forward direction than at 90 . This demonstrates that femtosecond lasers are capable of providing a time averaged neutron flux equivalent to commercial (2)(1)d(d, n)(2)He-3 generators with the advantage of a directional beam with picosecond bunch duration. (C) 2013 American Institute of Physics. [http://dx. doi. org/10.1063/1.4795723]