Tritium Assembly (TSTA) was a facility at the Los Alamos National Laboratory dedicated to the development and demonstration of technologies required for fusion-relevant deuterium-tritium processing. Tritium is sometimes used as a radiolabel. It has the advantage that almost all organic chemicals contain hydrogen, making it easy to find a place to put tritium on the molecule under investigation. It has the disadvantage of producing a comparatively weak signal. Tritium can be used in a betavoltaic device to create an atomic battery to generate electricity. Aside from chlorofluorocarbons, tritium can act as a transient tracer and has the ability to "outline" the
Isotope 40 different species referred to as "radioelements" (i.e. radioactive elements) between uranium and lead, although the periodic table only allowed for 11 elements from uranium to lead. Several attempts to separate these new radioelements chemically had failed. For example, Soddy had shown in 1910 that mesothorium (later shown to be Ra), radium (Ra, the longest-lived isotope), and thorium X (Ra) are impossible to separate. Attempts to place the radioelements in the periodic table led Soddy and Kazimierz Fajans independently to propose their radioactive displacement law in 1913, to the effect that alpha decay produced an element two places to the