[ RadSafe ] Micrometer-level naked-eye detection of caesium particulates in the solid state

Cary Renquist cary.renquist at ezag.com
Thu Feb 7 16:00:57 CST 2013

Interesting paper (it is an open access paper, so one can freely download it)

Seems like it would have limited utility as a practical mode of detection, but would likely be useful in experiments e.g. studying diffusion, etc.  
Not sure if I did my back of the envelope calc correctly, but I think that their 1 ppm detection level in soil would translate into about 98 µCi (3.63 MBq) -- seems too high, so I probably forgot to include something important....

Micrometer-level naked-eye detection of caesium particulates in the solid state


Large amounts of radioactive material were released from the Fukushima Daiichi nuclear plant in Japan, contaminating the local environment. During the early stages of such nuclear accidents, iodine I-131 (half-life 8.02 d) is usually detectable in the surrounding atmosphere and bodies of water. On the other hand, in the long-term, soil and water contamination by Cs-137, which has a half-life of 30.17 years, is a serious problem. In Japan, the government is planning and carrying out radioactive decontamination operations not only with public agencies but also non-governmental organizations, making radiation measurements within Japan. If caesium (also radiocaesium) could be detected by the naked eye then its environmental remediation would be facilitated. Supramolecular material approaches, such as host-guest chemistry, are useful in the design of high-resolution molecular sensors and can be used to convert molecular-recognition processes into optical signals. In this work, we have developed molecular materials (here, phenols) as an optical probe for caesium cation-containing particles with implementation based on simple spray-on reagents and a commonly available fluorescent lamp for naked-eye detection in the solid state. This chemical optical probe provides a higher spatial resolution than existing radioscopes and gamma-ray cameras.

Cary Renquist
Cary.renquist at ezag.com

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