Laser-driven neutron production from bulk and pitcher-catcher targets

As an important step in the development of the highly directional compact neutron source from the reaction $^{7}$Li(d,xn) [1] we have studied the laser-driven fusion neutron production d(d,n)$^{3}$He from bulk deuterated plastic targets and compared it to a pitcher-catcher target method using the same laser and detector arrangement. For laser intensities of up to I = 3.10$^{19}$ Wcm$^{2}$ it was found that the bulk targets produced a high yield (5.10$^{4}$ neutrons/steradian) beamed preferentially in the laser propagation direction. The inhibition of the deuteron acceleration by a proton rich contamination layer is likely to significantly reduce the pitcher-catcher neutron production. Two-dimensional particle-in-cell simulations were performed to model the deuteron beam acceleration, the results of which were coupled to a Monte Carlo code to calculate the expected neutron beam properties. Numerical analysis suggests the pitcher-catcher targets would become more efficient at higher laser intensities. This work was supported by DTRA and the NRL. [1] J. Davis et al., PPCF 52, 045015 (2010).