thallium208

Thallium-208 (Tl-208) is a radioactive isotope of the element thallium. It has an atomic number of 81 and a mass number of 208, corresponding to 81 protons and 127 neutrons. Tl-208 is not found in nature and is produced artificially in nuclear reactors or accelerators through neutron irradiation of stable thallium isotopes, followed by chemical separation to isolate the desired nuclide.

Decay properties: Tl-208 decays primarily by beta-minus emission to lead-208 (Pb-208), a stable isotope. The decay is often accompanied by gamma radiation from excited states of the daughter nucleus, which can be used to study the decay scheme and energy levels of Pb-208. The half-life of Tl-208 is relatively short on the scale of laboratory experiments, and values published in nuclear data libraries reflect this finite stability.

Production and handling: Tl-208 is generated in reactors or accelerator facilities by neutron capture on stable thallium isotopes, typically Tl-205, with subsequent chemical separation required to obtain a pure sample. As a radioactive beta emitter, it requires appropriate shielding and handling procedures to minimize radiation exposure.

Applications and safety: Tl-208 has limited practical uses and is mainly utilized in nuclear physics research to investigate decay properties and the Pb-208 end product. Due to its radiological and chemical toxicity, strict safety measures are essential in its production, handling, and disposal.

See also: thallium isotopes, lead-208, beta decay.