Cs-137

Cesium-137 (Cs-137) is a remarkable isotope with diverse applications in various fields. In this post, I’ll explore how Cs-137 is produced, its critical industrial roles, and its significance in gamma spectroscopy.

What is Cesium-137?

Cesium-137 is a radioactive isotope of cesium with a half-life of about 30.17 years. It decays via beta decay to metastable barium-137m (Ba-137m), which then decays to stable barium-137 (Ba-137) by emitting gamma radiation. The primary gamma photon produced has an energy of 662 keV, making Cs-137 a potent source of gamma rays.

How is Cesium-137 Produced?

Cs-137 is not found naturally but is produced through nuclear fission of uranium-235 (U-235) and plutonium-239 (Pu-239) in nuclear reactors. During the fission process, a variety of fission products are created, including Cs-137. The steps involved in the production are:

1. Nuclear Fission: U-235+n→Fission Products (including Cs-137)
2. Separation and Purification: After the fission reaction, Cs-137 is chemically separated and purified from other fission products for use in various applications.

Industrial Applications of Cesium-137

Cs-137 has several crucial industrial applications due to its gamma radiation and relatively long half-life:

1. Medical Radiotherapy: Cs-137 is used in brachytherapy, a type of radiotherapy where a sealed radiation source is placed inside or next to the area requiring treatment. It’s particularly effective in treating certain types of cancer.
2. Industrial Gauges: Cs-137 is used in industrial gauging applications to measure the thickness, density, or composition of materials. Its gamma rays penetrate materials, and the absorption levels help determine the desired properties.
3. Environmental Monitoring: Cs-137 is used to study soil erosion and sediment movement. Its presence in soil layers acts as a marker to trace soil displacement and accumulation patterns.
4. Security and Safety: Cs-137 is utilized in security devices, such as radiation detection instruments as a known energy  calibration source. That’s mandatory to calibrate the instrument for measuring radiation levels.

Cesium-137 in Gamma Spectroscopy

Gamma spectroscopy involves analyzing the energy and intensity of gamma rays emitted by radioactive substances. Cs-137 is a widely used calibration source in gamma spectroscopy due to its strong and well-defined gamma emission at 662 keV.

In gamma spectroscopy, Cs-137 provides a reliable standard for calibrating detectors and ensuring the accurate measurement of gamma radiation.