High deuteron and neutron yields from the interaction of a petawatt laser with a cryogenic deuterium jet

Abstract

A compact high-flux, short-pulse neutron source would have applications from nuclear astrophysics to cancer therapy. Laser-driven neutron sources can achieve fluxes much higher than spallation and reactor neutron sources by reducing the volume and time in which the neutron-producing reactions occur by orders of magnitude. We report progress towards an efficient laser-driven neutron source in experiments with a cryogenic deuterium jet on the Texas Petawatt laser. Neutrons were produced both by laser-accelerated multi-MeV deuterons colliding with Be and mixed metallic catchers and by d (d,n)3He fusion reactions within the jet. We observed deuteron yields of 1013/shot in quasi-Maxwellian distributions carrying ∼8−10% of the input laser energy. We obtained neutron yields greater than 1010/shot and found indications of a deuteron-deuteron fusion neutron source with high peak flux (>1022 cm−2 s−1). The estimated fusion neutron yield in our experiment is one order of magnitude higher than any previous laser-induced dd fusion reaction. Though many technical challenges will have to be overcome to convert this proof-of-principle experiment into a consistent ultra-high flux neutron source, the neutron fluxes achieved here suggest laser-driven neutron sources can support laboratory study of the rapid neutron-capture process, which is otherwise thought to occur only in astrophysical sites such as core-collapse supernova, and binary neutron star mergers.

Detailed characterization of kHz-rate laser-driven fusion at a thin liquid sheet with a neutron detection suite

“…As mentioned earlier, the recent paper by Jiao et al [ 51 ] inferred neutron generation directly from a solid deuterium target using only bubble detectors at the Texas Petawatt Laser. Furthermore, their neutron generation was accomplished at a rate of one shot per hour.…”

“…This confirms our experimental observation that, in our case, most of the neutron production happened in the bulk, which is also consistent with Willingale et al ’s earlier work [ 13 ] . Jiao et al [ 51 ] also used the deuteron distributions from 2D PIC simulations to estimate neutron reaction rates and similarly found increased neutron generation from the target near the interaction region.

Figure 9 A frame of the 2D3v simulation with s-polarization at 600 fs after the start of the simulation, showing the deuterated sheet in black and neutrons in red. The supplemental movie (see the section) shows the full evolution through 900 fs.

…”

“…This confirms our experimental observation that, in our case, most of the neutron production happened in the bulk, which is also consistent with Willingale et al's earlier work [13] . Jiao et al [51] also used the deuteron distributions from 2D PIC simulations to estimate neutron reaction rates and similarly found increased neutron generation from the target near the interaction region.…”