Isotopes of Helium - Heavier Helium Isotopes

Heavier Helium Isotopes

Although all heavier helium isotopes decay with a half-life of less than one second, researchers have created new isotopes through particle accelerator collisions to create unusual atomic nuclei for elements such as helium, lithium and nitrogen. The unusual nuclear structures of such isotopes may offer insight into the isolated properties of neutrons.

The shortest-lived isotope is helium-5 with a half-life of 7.6×10−22 second. Helium-6 decays by emitting a beta particle and has a half-life of 0.8 second. Helium-7 also emits a beta particle as well as a gamma ray. The most widely-studied heavy helium isotope is helium-8. This isotope, as well as helium-6, are thought to consist of a normal helium-4 nucleus surrounded by a neutron "halo" (containing two neutrons in 6He and four neutrons in 8He). Halo nuclei have become an area of intense research. Isotopes up to helium-10, with two protons and eight neutrons, have been confirmed. Helium-7 and helium-8 are hyperfragments that are created in certain nuclear reactions. 10He, despite being a doubly magic isotope, has a very short half-life.