Hydrogen is the only element whose isotopes have different names that remain in common use today: 2H is deuterium[6] and 3H is tritium.
Some Grand Unified Theories proposed in the 1970s predict that proton decay can occur with a half-life between 1028 and 1036 years.
[15] Deuterium, 2H (atomic mass 2.014101777844(15) Da), the other stable hydrogen isotope, has one proton and one neutron in its nucleus, called a deuteron.
Deuterium and its compounds are used as a non-radioactive label in chemical experiments and in solvents for 1H-nuclear magnetic resonance spectroscopy.
[nb 1][3] Traces of 3H occur naturally due to cosmic rays interacting with atmospheric gases.
It is used in fusion bombs, as a tracer in isotope geochemistry, and in self-powered lighting devices.
The most common way to produce 3H is to bombard a natural isotope of lithium, 6Li, with neutrons in a nuclear reactor.
[16][17] Deuterium–tritium fusion uses 2H and 3H as its main reactants, giving energy through the loss of mass when the two nuclei collide and fuse at high temperatures.
In the 1955 satirical novel The Mouse That Roared, the name quadium was given to the 4H that powered the Q-bomb that the Duchy of Grand Fenwick captured from the United States.
The two remaining protons were detected by the "RIKEN telescope", a device made of several layers of sensors, positioned behind the target of the RI Beam cyclotron.