Recent developments and perspectives on laser-driven neutron sources (LDNSs)

Since their discovery over 90 years ago, neutrons have become one of the premier tools in the study of the structure and dynamics of matter and materials. The main nuclear processes to generate a large number of free neutrons are fusion, fission, and spallation, which have been well established for using neutrons in broad areas of physics, material science, engineering, life sciences, and elsewhere. The vast majority of experiments that use neutrons as a probe require a directional, well-collimated beam of neutrons. Over the years, methods have been developed to deliver such neutron beams sufficiently, but it is still much desired to improve the efficiency of neutron sources. With the advent of high-powered lasers, laser-driven neutron sources suggest an attractive possibility. Laser photons can be converted to neutrons by accelerating particles (electrons, protons, and deuterons) and then either utilize hard x rays from, for example, electron acceleration to create photoneutrons or nuclear reactions, such as deuteron break-up. The maturity of such processes in recent years might have reached a state where such neutron sources are becoming useful and beneficial to the neutron community. In the present report, the current state-of-the-art of a laser-driven neutron source and its future development for neutron applications are presented, and existing sources are described. The basic physical principles of laser-driven neutron production and the current state-of-the-art of production techniques are outlined. The potential developments and the role of such sources in the landscape of neutron sources in the future are critically commented on.