Sr-90

Strontium-90 (Sr-90) is a radioactive isotope of strontium with a half-life of approximately 28.8 years. It is a byproduct of nuclear fission in reactors and during nuclear weapon explosions. Sr-90 undergoes beta decay, emitting high-energy beta particles as it transforms into yttrium-90, which also emits beta radiation. This isotope is considered hazardous due to its chemical similarity to calcium, allowing it to integrate into bones and teeth when ingested, posing health risks.

Sr-90 has practical applications in various fields. It is used as a power source in radioisotope thermoelectric generators (RTGs), particularly in remote or space applications, due to its reliable and long-lasting energy output. In medicine, Sr-90 is utilized in certain types of cancer treatments, such as for superficial eye and skin cancers, where beta radiation is applied to target affected tissues. Additionally, it serves as a beta radiation source in industrial applications, including thickness measurement in manufacturing processes.

Sr-90 is primarily found in controlled environments, such as medical facilities, research institutions, and industrial settings where it is used or stored securely. It is also present in the environment as fallout from nuclear weapons testing and nuclear accidents like Chernobyl and Fukushima. In contaminated areas, Sr-90 can accumulate in soil, plants, and the food chain, requiring ongoing monitoring and mitigation efforts.

Used as a reference source in beta-sensitive dosimeters. The spectrum has no characteristic peaks, all spectra of beta emitting sources are linear, making it very difficult to identify the isotope. Also, strontium-90 is often a companion of cesium-137, although it is extremely difficult to distinguish it from the other components of the spectrum.