neutrondetektion

Neutron detection refers to the identification and measurement of free neutrons, subatomic particles with no electric charge but a mass slightly greater than that of a proton. Neutrons are produced in various natural and artificial processes, including nuclear reactions, cosmic radiation, and spontaneous fission, making their detection important in fields such as nuclear physics, security, and materials science.

Detectors for neutrons operate on different principles depending on the energy range of the neutrons being measured. Thermal neutrons, which have been slowed down to energies comparable to room temperature, are commonly detected using materials that undergo nuclear reactions when absorbing neutrons. Boron trifluoride (BF₃) and helium-3 (³He) are widely used in gas-filled detectors, where neutron capture triggers ionization that can be amplified and recorded as an electrical signal. Solid-state detectors, such as those using lithium iodide or gadolinium compounds, also rely on neutron capture followed by scintillation or ionization.

Fast neutrons, with higher energies, require different detection methods. Organic scintillators, such as plastic or liquid scintillators, can detect fast neutrons indirectly by observing recoil protons produced when neutrons collide with hydrogen atoms in the material. Inorganic scintillators, such as lithium glass or cerium-doped materials, are also used, often combined with pulse-shape discrimination techniques to distinguish neutron interactions from gamma-ray events. Neutron-sensitive fission chambers, which use materials like uranium or plutonium, can detect fast neutrons by inducing fission events that generate measurable signals.

Advanced neutron detection systems may incorporate moderators, such as hydrogen-rich materials, to thermalize fast neutrons before detection, improving efficiency. Digital signal processing and computational analysis are increasingly employed to enhance detection sensitivity and reduce false positives. Applications of neutron detection range from monitoring nuclear facilities and ensuring radiation safety to non-proliferation efforts, medical imaging, and fundamental research in nuclear physics.