Context: Physicists from the US have successfully demonstrated a new way to detect radioactive materials from a distance using carbon-dioxide lasers.
Relevance of the Topic: Prelims: Basics of the technology and potential applications.
Avalanche-Based Laser for Radiation Detection
- The researchers used a carbon-dioxide laser to detect the alpha particles from a radioactive source (Caesium-137) located 10 m away.
- Mechanism:
- Radioactive decay: When radioactive material undergoes radioactive decay it releases charged particles (alpha, beta & gamma radiation). These charged particles ionise the air around it, i.e. separate its positive and negative charges, and create a state of matter called plasma.
- Avalanche breakdown: The negative charges (or electrons) can be accelerated to collide with other atoms of air, and release even more electrons. This is avalanche breakdown.
- Laser-based detection: The researchers used a carbon-dioxide laser emitting long wave infrared radiation to accelerate the electrons, and making them emit light (optical backscatter). The sensors placed near the laser were able to detect the alpha particles from the radioactive source.
Advantages of the Laser-based detection Technique
- Detecting low concentration radioactive source: The ability of lasers to induce (initiate) electron avalanches can be utilised to detect even very low concentration of ionisation. The lasers can be scaled to detect gamma rays that travel much farther in air than alpha particles, and have low density of ionisation.
- Scalability: The researchers are scaling up the current detection capabilities to detect radiation from distances over 100 metres.
Potential Applications
- National security: Detection of illicit possession or smuggling of radioactive substances, especially at airports or borders.
- Nuclear safety: Detection of radiation leakage from Nuclear reactors and installations.
- Environmental monitoring: Tracking radioactive contamination in air, water, soil, mines, space etc.
- Exploration of naturally occurring radioactive materials.