A Route to the Brightest Possible Neutron Source?

Abstract

We review the potential to develop sources for neutron scattering science and propose that a merger with the rapidly developing field of inertial fusion energy could provide a major step-change in performance. In stark contrast to developments in synchrotron and laser science, the past 40 years have seen only a factor of 10 increase in neutron source brightness. With the advent of thermonuclear ignition in the laboratory, coupled to innovative approaches in how this may be achieved, we calculate that a neutron source three orders of magnitude more powerful than any existing facility can be envisaged on a 20- to 30-year time scale. Such a leap in source power would transform neutron scattering science.

Research opportunities with compact accelerator-driven neutron sources

“…Inertial fusion employs a small (millimeter size) d-t pellet that can be ignited in principle by a high-power laser beam. Recently, Taylor et al [13] suggested a super-high-flux neutron source based on laser-ignited inertial fusion. A single target is a pellet of d-t mixture, which, upon ignition, sustains the fusion reaction…”

“…TOF facilities at larger pulsed neutron sources such as the n_TOF-CERN are useful for measurements of capture cross sections up to hundreds of MeV, as well as decay half-lives of the associated (n,) reactions. For example, high-precision data of the energy dependence of neutron-source reactions, e.g., 13 C(,n) 16 O and 11 Na(,n) 25 Mg, and neutron-poison reactions, e.g., 14 N(n,p) 14 C, 16 O(n,) 17 O, and 25 Mg(n,) 26 Mg, are critical to s-process calculation of the convection and mixing nature during carbon-nitrogen-oxygen burning stages. An interesting situation arises at the s-process branching points where matter flows can occur by both neutron capture and decay.…”

New sources and instrumentation for neutrons in biology

“…Reactorbased fission sources have been providing neutron beams for more than 60 years and are still the majority among neutron sources. Despite the fact that the last 40 years have only seen a factor of 10 increase in the neutron source brightness [4], significant upgrades in neutron productivity have happened through the installation of hot and cold sources, neutron guides and various developments in instrumentation to match source technology. It is far beyond this review to detail these developments, but new sources in particular have benefited from these upgrades.…”

“…Laser inertial fusion has also been suggested [4] as a future pulsed neutron source, in which a sequence of very short laser-light pulses ignites a small pellet of D,T fuel, producing a short pulse of neutrons. The technical complexity has however been a strong argument against the expected factor of 2-3 potential gain over optimized third generation spallation sources [13].…”

Experimental demonstration of a compact epithermal neutron source based on a high power laser

“…Although sources such as the National Ignition Facility report record yield in fusion neutrons per pulse [29,30], its scale and repetition rate are inadequate for any credible application related to neutron science. On the other hand, the repetition rates achievable on smaller scale installations could still be too low to guarantee successful exploitation for the aforementioned applications.…”