Radiacode — Pocket-Sized Next-Generation Geiger Counter and Gamma Spectrometer

Thorium-232 (Th-232) is a naturally occurring radioactive isotope of thorium and the most stable and abundant isotope of this element. It has an extremely long half-life of approximately 14 billion years, making it three times older than the Earth itself. Th-232 undergoes alpha decay, eventually leading to a series of decay products that form the thorium decay series. Thorium-232 (Th-232) itself emits almost no gamma radiation, as it primarily undergoes alpha decay. However, the gamma radiation typically associated with Th-232 comes from its decay chain, not from the isotope itself.As Th-232 decays, it produces a series of radioactive daughter isotopes — such as Ra-228, Ac-228, Th-228, Bi-212, Pb-212, and Tl-208 — many of which emit gamma rays at specific energies. One of the most characteristic gamma emissions from this chain is at 2614 keV, which comes from Tl-208. This is one of the most intense natural gamma lines and a strong indicator of thorium-based radioactivity. Other noticeable lines include those around 583 keV, 911 keV, and 969 keV.

Th-232 is primarily used in the nuclear energy sector. It serves as a fertile material in nuclear reactors, where it can be transformed into uranium-233, a fissile material that can sustain a nuclear chain reaction. This property makes it a potential fuel for advanced thorium-based nuclear reactors, which are being researched for their safety, efficiency, and reduced long-lived radioactive waste compared to traditional uranium-based reactors. Th-232 is also used in high-temperature ceramics and magnesium-thorium alloys, particularly in aerospace and industrial applications.

Thorium-232 is naturally found in minerals such as monazite and thorite, which are rich in thorium. These minerals are widely distributed in the Earth's crust, especially in regions with heavy mineral sands. Th-232 contributes to natural background radiation and is often present in trace amounts in soils and rocks. Due to its natural abundance and potential applications, it is of significant interest in both industrial and scientific fields.