Environmental isotopes isotope. For example, H (tritium) is a radioactive isotope of hydrogen. It decays into He with a half-life of ~12.3 years. By comparison, stable isotopes are more stable, decaying much more slowly and having much longer half-lives. Examples of stable isotopes are Sr and Sr. These isotopes of strontium have half-lives on the order of billions of years or are unmeasured because of how stable they are. On timescales that geologists and environmental scientists investigate, these isotopes are stable. Both of these types of isotopes are useful to scientists. Radioactive isotopes are generally more useful on shorter timescales, such as
Inertial confinement fusion the layer to be closely monitored ensuring its "smoothness". Cryogenic targets filled with a deuterium tritium (D-T) mixture are "self-smoothing" due to the small amount of heat created by the decay of the radioactive tritium isotope. This is often referred to as "beta-layering". Certain targets are surrounded by a small metal cylinder which is irradiated by the laser beams instead of the target itself, an approach known as ""indirect drive"". In this approach the lasers are focused on the inner side of the cylinder, heating it to a superhot plasma which radiates mostly in X-rays. The X-rays from this plasma