Tritium

A tritium glowring, which uses tritium gas to produce light.

A gaseous tritium light source.

Chemical structure of tritiated pyridine.

A watch with tritium-illuminated hands and markers.

Tritium is a radioactive isotope of hydrogen with the symbol T or _H. It contains one proton and two neutrons in its nucleus, making it three times heavier than the most common hydrogen isotope, protium. Tritium is rare on Earth and is produced naturally in the upper atmosphere when cosmic rays interact with atmospheric gases. It can also be produced artificially in nuclear reactors.

Properties

Tritium is a beta emitter, which means it emits beta particles during radioactive decay. The beta particles emitted by tritium are of low energy and can be stopped by a sheet of paper or human skin. This makes tritium relatively safe to handle in small quantities, although it can pose a health risk if ingested or inhaled.

Tritium has a half-life of approximately 12.32 years, after which it decays into helium-3. This property makes it useful in various applications, particularly in self-luminous devices.

Applications

Tritium is widely used in self-luminous devices, such as exit signs, watch dials, and gun sights. These devices contain small amounts of tritium gas sealed in glass tubes coated with a phosphorescent material. The beta particles emitted by tritium excite the phosphor, causing it to glow without the need for an external power source.

In addition to its use in lighting, tritium is also used in nuclear fusion research as a fuel. It is a key component in hydrogen bombs and is used in combination with deuterium to enhance the explosive yield.

Production

Tritium is produced in nuclear reactors by irradiating lithium-6 with neutrons. The reaction produces tritium and helium-4. This process is used to produce tritium for both civilian and military applications.

Environmental and Health Concerns

Tritium can be released into the environment from nuclear facilities, and its presence in the environment is monitored due to its radioactive nature. While tritium is considered to be of low radiotoxicity, it can still pose a risk if it enters the human body in significant amounts.

Related pages

• Hydrogen
• Isotopes of hydrogen
• Nuclear fusion
• Radioactive decay