Cesium-137

Cesium-137

Cesium-137 (Cs-137) is a radioactive isotope of cesium which is formed as a fission product by the nuclear fission of uranium and plutonium. It is one of the most common byproducts of nuclear fission and is a significant component of nuclear fallout.

Properties

Cesium-137 has a half-life of approximately 30.17 years. It decays by beta emission to a metastable nuclear isomer of barium, barium-137m (Ba-137m), which is responsible for the gamma radiation emissions. The decay process can be represented as follows:

\( \ce{^{137}_{55}Cs -> ^{137m}_{56}Ba + \beta^- + \bar{\nu}_e} \)

The gamma radiation emitted by Ba-137m is what makes Cs-137 useful in various applications, such as in medical radiation therapy and industrial radiography.

Applications

Cesium-137 is used in a variety of applications due to its radioactive properties:

• Medical Applications: Cs-137 is used in radiotherapy for the treatment of certain types of cancer. Its gamma radiation is effective in killing cancer cells.

• Industrial Applications: It is used in industrial radiography to inspect the integrity of welds and metal structures. Cs-137 sources are also used in moisture and density gauges.

• Scientific Research: Cs-137 is used as a tracer in hydrological studies to understand soil erosion and sedimentation processes.

Environmental Impact

Cesium-137 is a major concern in the context of nuclear accidents and fallout. Due to its relatively long half-life and high solubility in water, it can spread easily in the environment and enter the food chain. Notable incidents involving Cs-137 include the Chernobyl disaster and the Fukushima Daiichi nuclear disaster.

Chernobyl Disaster

The Chernobyl disaster in 1986 released a significant amount of Cs-137 into the environment. The isotope contributed to the long-term contamination of the surrounding areas, leading to the establishment of the Chernobyl Exclusion Zone.

Fukushima Daiichi

In 2011, the Fukushima Daiichi nuclear disaster also resulted in the release of Cs-137, leading to contamination of land and water in the surrounding regions. Efforts to decontaminate affected areas are ongoing.

Safety and Handling

Due to its radioactive nature, Cs-137 must be handled with care. Proper shielding and safety protocols are essential to protect against its beta and gamma radiation. In medical and industrial settings, Cs-137 sources are typically encapsulated to prevent leakage and exposure.

See Also

• Radioactive decay
• Nuclear fission
• Radiation therapy
• Nuclear fallout

References

• International Atomic Energy Agency (IAEA) publications on radioactive isotopes.
• World Health Organization (WHO) guidelines on radiation safety.

External Links

• International Atomic Energy Agency
• World Health Organization