Neutron

A neutron is an electrically neutral subatomic particle found in most atomic nuclei. It is a baryon made of one up quark and two down quarks.

Quark: An elementary particle that combines with other quarks to form hadrons such as protons and neutrons. Two down quarks and one up quark compose each neutron.
Beta decay: A radioactive process in which a neutron or proton changes into the other through the weak interaction. In beta-minus decay, a neutron becomes a proton while emitting an electron and an antineutrino.
Neutron scattering: A set of techniques that use neutron deflection to study the structure and motion of matter. Neutrons reveal atomic positions and magnetic behavior inside materials.
Proton: A positively charged baryon found in atomic nuclei, composed of two up quarks and one down quark. It shares nuclear membership with the neutron but determines an element's atomic number.
James Chadwick: The British physicist who discovered the neutron in 1932 through experiments on beryllium radiation. His measurements established that the penetrating radiation consisted of neutral particles with mass comparable to protons.
Baryon: A hadron composed of three quarks, including protons and neutrons. Neutrons belong to this family of three-quark particles.
Neutron capture: A nuclear reaction in which an atomic nucleus absorbs a neutron. Adding a neutron can create a heavier isotope or trigger subsequent radioactive decay.
Neutron activation analysis: An analytical method that identifies elements by measuring radiation from neutron-irradiated samples. Neutron capture makes sample nuclei radioactive in element-specific ways.
Electron: A negatively charged elementary particle found outside atomic nuclei in ordinary atoms. Unlike the neutron, it is elementary, negatively charged, and not a nuclear constituent.
Ernest Rutherford: The physicist who established the nuclear model of the atom and proposed a neutral nuclear particle. His earlier proposal anticipated the neutron that Chadwick later identified.

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