Tritium of tritium oxide introduced into upper layers of the oceans have been used in the years since then to measure the rate of mixing of the upper layers of the oceans with their lower levels. Tritium is an isotope of hydrogen, which allows it to readily bind to hydroxyl radicals, forming tritiated water (HTO), and to carbon atoms. Since tritium is a low energy beta emitter, it is not dangerous externally (its beta particles are unable to penetrate the skin), but it can be a radiation hazard when inhaled, ingested via food or water, or absorbed through the skin. HTO
Atomic vapor laser isotope separation Atomic vapor laser isotope separation Atomic vapor laser isotope separation, or AVLIS, is a method by which specially tuned lasers are used to separate isotopes of uranium using selective ionization of hyperfine transitions. As compared to gas centrifuges the AVLIS process provides high energy efficiency, high separation factors, and a low volume of radioactive waste. A similar technology, using molecules instead of atoms, is molecular laser isotope separation (MLIS). The absorption lines of and U differ slightly due to hyperfine structure; for example, the U absorption peak of 502.74 nanometers shifts to 502.73 nm in U. AVLIS uses tunable dye