Deuterium z-pinch as a powerful source of multi-MeV ions and neutrons for advanced applications

Abstract

A novel configuration of a deuterium z-pinch has been used to generate a nanosecond pulse of fast ions and neutrons. At a 3 MA current, the peak neutron yield of (3.6 ± 0.5) × 1012 was emitted within 20 ns implying the production rate of 1020 neutrons/s. High neutron yields resulted from the magnetization of MeV deuterons inside plasmas. Whereas deuterons were trapped in the radial direction, a lot of fast ions escaped the z-pinch along the z-axis. A large number of >25 MeV ions were emitted into a 250 mrad cone. The cut-off energy of broad energy spectra of hydrogen ions approached 40 MeV. The total number of >1 MeV and >25 MeV deuterons were 1016 and 1013, respectively. Utilizing these ions offers a real possibility of various applications, including the increase of neutron yields or the production of short-lived isotopes in samples placed in ion paths. On the basis of our experiments with various samples, we concluded that a single shot would have been sufficient to obtain GBq positron activity of 13N isotopes via the 12C(d,n)13N reaction. Furthermore, the first z-pinch generated neutron radiograph produced by ≈20 ns pulses is presented in this paper.

Hybrid MHD/PIC simulation of a deuterium gas puff z pinch

“…It was shown that the observed neutron spectra could be explained by a suprathermal distribution of deuterons with a power law fall off in the ion energy distribution function at large energy. These high energy deuterons with energy up to 40 MeV (highest achievement for Z-pinches experiments) were detected in [6,7]. The mechanism of generation of such deuterons is still not clear [8].…”

“…Processes of deuterium ionisation and DD fusion have been considered with the help of direct simulation Monte Carlo (DSMC) method. The geometric configuration of the computational domain has been chosen in order to match the geometry of the experiment [6,7]. Figure 1 shows sketch of the experimental setup and the computational domain.…”

“…The shell parameters at this point are the additional parameters of the problem. We varied velocity and linear mass distribution of the outer plasma shell in order to get the neutron yield as close to the results [6,7] as possible. Figure 2 shows an example of the initial density distribution.…”

“…Recent experiments [6,7] made in a novel configuration have shown that the neutron yields can reach 3.6×10 12 at current about of 3 MA. Earlier, this neutron yield could be surpassed only on the 15-MA pinch.…”

“…Earlier, this neutron yield could be surpassed only on the 15-MA pinch. Energy neutron spectrum obtained in experiments [6,7] has a high energy non-Maxwellian tail. Possible reasons of this high energy tail origin are discussed, for example, in [8].…”