Isotopes: Hydrogen-3

Physical Characteristics:
  • Half-life: 12.3 years
  • Emissions: Beta particles with a maximum energy of 18.6 keV and an average energy of 5.7 keV.
  • Maximum Range in Air: 4.7 mm in air; 6 mm in tissue.
  • Fraction transmitted through the dead layer of the skin: none
Dose and Shielding:
  • Dose rate to the skin at 10 cm: None
  • Dose rate to epidermal basal cells from skin contamination of 1 mCi/cm2: None
  • Shielding: None needed.
  • Annual Limit on Intake (ALI): 80 millicuries via ingestion, assuming intake as tritiated water. The ingestion of one ALI will produce a dose of 5 rem.

Liquid scintillation counting is the preferred method for detecting H-3. Most G-M detectors will not detect the presence of H-3.


H-3 contamination cannot be detected with a G-M meter, and special precautions are needed to keep the work environment clean. The regular use of wipe testing, using a liquid scintillation counter, is the only way to insure that your work space does not contain contamination.

Waste Disposal:
  • Solid Wastes/Liquid Scintillation Wastes: through the Off-Site Radioactive Waste Disposal Program