Some nuclides can be induced to eject a neutron by gamma radiation. One such nuclide is Be ; its photodisintegration is significant in nuclear astrophysics, pertaining to the abundance of beryllium and the consequences of the instability of Be. This also makes this isotope useful as a neutron source in nuclear reactors. Another nuclide, Ta, is also known to be readily capable of photodisintegration; this process is thought to be responsible for the creation of Ta, the only primordial nuclear isomer and the rarest primordial nuclide.