Wed Mar 26 08:37:20 UTC 2025: ## Scientists Develop Long-Range Radioactive Material Detector

**Chennai, India – March 27, 2025** – A team of US physicists has made a significant breakthrough in radioactive material detection, developing a new technique capable of identifying such materials from a distance using carbon-dioxide lasers. This advancement, published in *Physical Review Applied* on March 4th, promises significant improvements in national defense and emergency response capabilities.

The technique leverages the phenomenon of avalanche breakdown. Radioactive decay releases charged particles that ionize the air, creating plasma. A carbon-dioxide laser, emitting long-wave infrared radiation, accelerates these electrons, leading to a measurable optical backscatter. This backscatter is amplified, significantly enhancing detection sensitivity. The researchers successfully detected alpha particles from a source 10 meters away—a tenfold improvement over previous methods.

The use of long-wavelength lasers is key, minimizing unwanted ionization effects and allowing detection of low seed electron concentrations. Fluorescence imaging further illuminated the process, enabling the creation of a predictive mathematical model.

While the current setup detected alpha particles, the researchers suggest the technique could be adapted to detect gamma rays, such as those emitted by Caesium-137, from approximately 100 meters with scaled-up optics. However, extending the range to kilometers presents challenges due to signal weakening, background radiation, and atmospheric interference. Despite these limitations, the breakthrough represents a substantial leap forward in remote radioactive material detection technology.

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