229th

229Th, also known as thorium-229, is a radioactive isotope of thorium with a half-life of approximately 7,340 years. It is a member of the thorium decay series, which begins with the naturally occurring isotope thorium-232. The decay of 229Th proceeds through a series of alpha and beta decays, ultimately leading to the stable isotope lead-208.

Thorium-229 is of particular interest in the field of nuclear physics due to its unique nuclear structure. It has an excited state, known as the isomeric state, with an energy of 7.6 eV above the ground state. This isomeric state has a half-life of about 1.9 milliseconds, making it a metastable state. The transition between the isomeric state and the ground state is of great interest because it is one of the few nuclear transitions that can be induced by laser light, a process known as nuclear optical pumping.

The study of 229Th and its isomeric state has the potential to lead to the development of new types of nuclear clocks, which could be more accurate than current atomic clocks. Additionally, the unique properties of 229Th could be used to develop new types of nuclear batteries and other energy applications.

Despite its potential, the study of 229Th is still in its early stages. The precise energy of the transition between the isomeric state and the ground state is not yet known, and the development of a laser that can induce this transition is a significant technical challenge. However, ongoing research is making progress in this area, and the potential applications of 229Th are an active area of study in nuclear physics.