Search Menu
Photonics Media Photonics Buyers' Guide Photonics EDU Photonics Spectra BioPhotonics EuroPhotonics Industrial Photonics Photonics Showcase Photonics ProdSpec Photonics Handbook
More News
Email Facebook Twitter Google+ LinkedIn Comments

Improved Detection of Radioactivity’s Warm Glow

Photonics Spectra
Oct 2006
You would not want to drink radioactively contaminated water, nor would you want your children to play on radioactively contaminated soil, but it is quite possible that some uranium cannot be detected using current techniques.


For 100 years, scientists have known that uranium emits green-yellow fluorescence upon exposure to UV radiation, enabling its detection. However, water and sediment typically contain other heavy metals and have a neutral pH, which obfuscate the signal because of the formation of colorless uranyl-carbonate complexes. Zheming Wang and colleagues at the Pacific Northwest National Laboratory in Richland, Wash., used a technique that involved freezing the soil and water samples prior to focusing the UV laser beam, revealing uranium that was not previously detected.

At the American Chemical Society’s 232nd annual meeting in San Francisco in September, the researchers reported that they cooled their soil samples to –267 °C, which is near the temperature of liquid helium. They analyzed the water and soil using high-power pulsed lasers and intensified, gated imaging CCD detectors to perform time-resolved laser-induced fluorescence spectroscopy and imaging spectromicroscopy. They found that, at the low temperature, uranium in soil and water samples manifested enhanced spectral resolution and intensity.

The emission of light or other electromagnetic radiation of longer wavelengths by a substance as a result of the absorption of some other radiation of shorter wavelengths, provided the emission continues only as long as the stimulus producing it is maintained. In other words, fluorescence is the luminescence that persists for less than about 10-8 s after excitation.
As We Go To PressBreaking NewsfluorescencefreezingMicroscopyPresstime Bulletinradioactively contaminated waterSensors & Detectors

Terms & Conditions Privacy Policy About Us Contact Us
back to top
Facebook Twitter Instagram LinkedIn YouTube RSS
©2019 Photonics Media, 100 West St., Pittsfield, MA, 01201 USA,

Photonics Media, Laurin Publishing
x Subscribe to Photonics Spectra magazine - FREE!
We use cookies to improve user experience and analyze our website traffic as stated in our Privacy Policy. By using this website, you agree to the use of cookies unless you have disabled them.