Nuclear physics
Sievert (Sv)
The SI unit of equivalent dose of ionizing radiation, accounting for biological effect.
A whole-body dose of about 1 Sv causes acute radiation syndrome; 4-6 Sv kills roughly half of untreated victims; 8 Sv is usually fatal. Background radiation is about 2-3 millisieverts per year. Aircrew and astronauts receive notably higher doses.
Related terms
Acute Radiation Syndrome
The constellation of medical symptoms following a high dose of ionizing radiation, including nausea, immune-system failure, hemorrhage, and death.
Gamma Radiation
High-energy electromagnetic radiation emitted by nuclear processes, capable of penetrating most materials and damaging living tissue.