Schematic of the dual target configuration. A laser pulse accelerates deuterium ions from the primary target (e.g., Au with rear D layer) toward the secondary target (e.g., 25 mm ) to create neutrons through fusion events in the secondary target.
(a) Angle and energy [(b) 0°, (c) 90°] distributions of emitted neutrons for monoenergetic, normally incident ions of energy. 1 MeV (solid), 1 MeV (dot), and 10 MeV (dashed). Plots linearly scaled individually such that the maximum neutron emission in the angular and 0° plots are unity. Total yields: , , and . Yields in the forward direction (for comparison with Ref. 4): , , and .
Monte Carlo calculated neutron yields from the LULI (dashed) and Trident (solid) lasers as a function of (a) angle and energy in the (b) 0° and (c) 90° directions.
All dashed correspond to and solid to . Secondary target . (a) Calculated deuteron spectrum achievable at the ELI laser facility using the scaling in Ref. 18. (b) Projected angular neutron distribution. (c) Neutron energy distribution at 0° and (d) 90°.
Schematic of microlens focusing technique (Ref. 11). Divergent deuterons are focused using a hollow cavity excited by a laser pulse. The resulting neutrons from the secondary target are consequently less divergent than without the microlens.
Energy distribution at (a) 0° and (b) 90° of neutrons emitted from thin targets with incident ion energies of 1 MeV (solid), 10 MeV (dotted), and 50 MeV (dashed).
[(a) and (b)] Incident ion and [(c) and (d)] emergent neutron energy distributions for thin targets and microlens focusing. [(a) and (c)] LULI spectrum with a microlens centered at 12 MeV and selection width of 0.1 MeV. [(b) and (d)] Moderate ELI spectrum with a microlens centered at 200 MeV and selection width of 5 MeV.
Comparison of conventional sources of neutron production with ultraintense laser facility capabilities. Yields represent “on target” neutron flux, for which the laser facilities assume a 1 m distant target, 20° divergent neutrons, and 1 Hz repetition rate for LULI and 1/60 Hz repetition for ELI.
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