Be9

Be-9, or 9Be, is the only stable isotope of the element beryllium. It has four protons and five neutrons (Z = 4, A = 9) and, in its ground state, a nuclear spin of 3/2−. As a result, Be-9 is stable and does not undergo radioactive decay.

Natural occurrence and abundance: In nature, beryllium is found almost entirely as Be-9. The element itself is relatively rare in Earth's crust, but virtually all of it is in the Be-9 form. Be-9 is also produced in cosmic ray interactions and in certain stellar environments, though its overall cosmic abundance remains low.

Nuclear properties: Be-9 is a light nucleus with a relatively simple structure that has been studied to understand clustering phenomena in light nuclei. Its stability and simple composition make it a common target in experimental nuclear physics.

Production and uses: Be-9 is widely used in laboratory settings as a target material for neutron production. When bombarded with alpha particles, Be-9 can undergo the reaction 9Be(α,n)12C, producing neutrons that are used for detector calibration and various neutron-related experiments. Due to its low atomic mass and favorable neutron scattering properties, beryllium is also employed as a neutron reflector or moderator in some nuclear applications.

Safety considerations: Beryllium and its compounds are toxic, with inhalation of dust or fumes capable of causing chronic lung disease known as berylliosis. Proper engineering controls, protective equipment, and handling procedures are essential in any setting that uses Be or Be-9.

See also: Beryllium, Isotopes of beryllium, Nuclear physics.