Tritium (3H) is a short-lived radioactive isotope of hydrogen which decays by beta emission to stable 3He. The half-life of tritium is 12.43 years.
Tritium analyses are reported in units of concentration called Tritium Units (TU), where one TU is one tritium atom in 1018 atoms of hydrogen. Tritium analyses can also be reported in units of radioactivity (picocuries) per unit volume. One picocurie is 2.22 disintegrations per minute (dpm). A liter of water with a tritium concentration of 1 TU would yield about 7.1 dpm, which is equivalent to 3.2 picocuries per liter (pC/l). At Geochron, the tritium activity in water samples is determined by liquid scintillation. By using a long (2000 minute) counting period, we obtain a detection limit of about 4 TU or 14 pC/l.
Geochron's tritium detection limit may not be appropriate for some groundwater studies. Feel free to contact us to discuss the applicability of our service to your particular problem.