The physical mechanisms of neutron detection

Abstract

Neutrons do not directly ionise the medium they pass through, unlike charged particles. Neutron detection is then based on nuclear reactions in which the neutron is typically lost and charged particles and/or γ-rays are generated in the final state. These are subsequently detected by appropriate sensors of various types, such as gas, scintillation, and solid-state detectors. Neutrons generated at large scale facilities (fission reactors or accelerator-driven plants) typically cover a very wide energy range. The nuclear reactions that are found to be effective at different energies make neutron detection on the one hand complex from an instrumental point of view, and on the other hand interesting from the point of view of the physics underlying the approach to be used. This article aims at presenting and discussing the main features of the nuclear reactions of interest in neutron detection in different energy ranges, and the physical processes that take place in typical sensors used as detection tools. This approach is intended to describe the entire physical process, from neutron-nucleus interaction to the physical sensor response, that represents the detection event.

Keywords:

• Neutron
• nuclear reactions
• sensors

Acknowledgments

The author warmly thank Dr. Giuseppe Celentano (ENEA, Superonductivity Laboratory), Dr. Gerardo Claps (ENEA, Magnetic Confinement Laboratory ) and Dr. Nicholas Terranova (ENEA, Nuclear Technologies Laboratory) for precious comments and discussions.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

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Antonino Pietropaolo

Antonino Pietropaolo is researcher at the Italian National Agency for New Technologies, Energy and Sustainable Economic Development. He works at the Nuclear Department – Nuclear Technologies Laboratory and is staff member of the Frascati Neutron Generator, the accelerator-driven fusion neutron source operating at the ENEA's Frascati Research Centre. He graduated in Physics at La Sapienza University of Rome and received his PhD in Physics at the University of Rome Tor Vergata. He has worked in the development of epithermal neutron detectors, using electronvolt neutron spectroscopy for the investigation of hydrogen-containing molecular systems. Since 2000 he is member of the Italian Society for Neutron Science. His present main research activities are related to development of high intensity fusion neutron sources, fast and thermal neutron detectors and use of fusion neutrons for medical radioisotopes production.