Observation of neutron spectrum produced by fast deuterons via ultraintense laser plasma interactions

Abstract

We report the first precise spectral measurement of fast neutrons produced in a deuterated plastic target irradiated by an ultraintense sub-picosecond laser pulse. The 500-fs, 50-J, 1054-nm laser pulse was focused on the deuterated polystyrene target with an intensity of 2 x 10(19) W/cm(2). The neutron spectra were observed at 55 degrees and 90 degrees to the rear target normal. The neutron emission was 7 x 10(4) per steradian for each detector. The observed neutron spectra prove the acceleration of deuterons and neutron production by d(d,n)3He reactions in the target. The neutron spectra were compared with Monte Carlo simulation results and the deuteron's directional anisotropy and energy spectrum were studied. We conclude that 2% of the laser energy was converted to deuterons, which has an energy range of 30 keV up to 3 MeV.

Generation of high-energy neutrons with the 300-ps-laser system PALS

“…A typical signal of the scintillation detector that is induced by γ radiation and neutrons coming from nuclear reactions a stationary target, such as those derived and discussed in [10,29] . The dependence of neutron energy on the energy of deuterons and on the direction of observation is shown in Figure 4.…”

High-energy ion generation by short laser pulses

“…27d). The total numbers of fast electrons and protons with an energy ≥3 MeV are ~10 11 and ~10 10 , respectively. Although lasers with a pulse duration ≤100 fs are not optimal for high-energy ion generation [63], this provides hope that a laser with an energy of 100-200 mJ can be used to initiate most conventional nuclear reactions through the practical use of fast protons.…”

“…The results obtained from some experiments [6,[10][11][12] provide evidence that the observed MeV-ions were generated and accelerated in plasma at the front of the target , conflicting with experiments [3,4,[13][14][15], which indicated that proton acceleration took place at the back of the target . The electrostatic model of ion acceleration suggests that the origin of the ions was the same for both of these experiments and that the only difference was in the plasma thickness, i.e., whether or not the plasma extended to the rear surface.…”

Collisionless electrostatic shock generation using high-energy laser systems

“…In 2000s, experiments on ion acceleration in the radial direction to the incident high-intensity laser beam by a radial collisionless ES shock in an underdense plasma have been reported [71][72][73]. Nilson et al have reported the experimental generation of high Mach-number ES shock in an underdense plasma with a high-intensity laser beam [74], with an experimental condition similar to that in [72].…”