Numerical investigation of spallation neutrons generated from petawatt-scale laser-driven proton beams

Abstract

Due to their high cost of acquisition and operation, there are still a limited number of high-yield, high-flux neutron source facilities worldwide. In this context, laser-driven neutron sources offer a promising, cheaper alternative to those based on large-scale accelerators, with, in addition, the potential of generating compact neutron beams of high brightness and ultrashort duration. In particular, the predicted capability of next-generation PetaWatt (PW)-class lasers to accelerate protons beyond the 100 MeV range should unlock efficient neutron generation through spallation reactions. In this paper, this scenario is investigated numerically through particle-in-cell and Monte Carlo simulations, modeling, respectively, the laser acceleration of protons from thin-foil targets and their subsequent conversion into neutrons in secondary heavy-ion targets. Laser parameters relevant to the 1 PW PETAL and 1-10 PW Apollon systems are considered. Under such conditions, neutron fluxes exceeding 10 '( n cm ,' s ,. are predicted, opening up attractive fundamental and applicative prospects.

Micro-size picosecond-duration fast neutron source driven by a laser–plasma wakefield electron accelerator

“…However, it is still too difficult for traditional fast neutron source with 1 ns pulse duration to acquire FNAS which can exhibit the finer structure of some resonance absorption peaks [14,59] . For example, there is a resonance peak of 16 O at ∼1.65 MeV with typic FWHM about 5 keV which is from the theoretical calculation [60] . Fortunately, the LWFA based neutron source (36 ps duration) has great advantage in accurate measurement of this kind of narrow absorption cross-sections, due to the E.R.…”

“…However, it is still too difficult for a traditional fast neutron source with 1 ns pulse duration to acquire FNAS, which can exhibit the finer structure of some resonance absorption peaks [14,59] . For example, there is a resonance peak of 16 O at approximately 1.65 MeV with typical FWHM of about 5 keV, which is from the theoretical calculation [60] . Fortunately, the LWFAbased neutron source (36 ps duration) has a great advantage in the accurate measurement of this kind of narrow absorption cross-section, because the ER can reach approximately 100 eV @ 1.65 MeV and 20 m. Although the yield of the ultra-short pulsed fast neutron source based on LWFA is less than 10 6 per shot, it is also feasible to acquire fine FNAS by accumulating enough shots, for example, hundreds of shots.…”

“…For example, laser plasma accelerating electrons/ions can induce photofission [15] , spallation [16] , fusion [13] reactions and generate fast neutron source [14] . Because of the uncharged property of neutron, it has different properties from charged particles or electromagnetic radiation when interacting with matters, which can result in obtaining complementary information.…”

“…Laser-plasma accelerators have attracted significant interest over the last few decades [1][2][3][4] due to their high acceleration gradients and beam currents [5] ; they not only enable GeV electron [6] and hundred-MeV ion [7] accelerators to be reduced to a length scale of centimeters, but also can drive secondary radiation [8][9][10] and particle sources [11][12][13][14] with ultra-high brightness/flux. For example, laser-plasma accelerating electrons/ions can induce photofission [15] , spallation [16] and fusion [13] reactions, and generate a fast neutron source [14] . Because of the uncharged property of neutrons, they have different properties from charged particles or electromagnetic radiation when interacting with matter, which can result in obtaining complementary information.…”

High-flux neutron generation by laser-accelerated ions from single- and double-layer targets

“…Provided that their temporal contrast can be much improved over present performance, through, e.g., the use of plasma mirrors 29 , we can surmise that those lasers, which already surpass the 10 21 W cm −2 intensity level 24,30 , can boost the ion acceleration to the 100 MeV range. One appealing prospect towards high-efficiency, laser-based neutron sources would be to couple such energetic ion beams with heavy-ion converters to approach the spallation regime of neutron generation, characterised by high neutron multiplicity 31,32 .…”