Millimeter-level naked-eye detection of Cesium location at solid surface

Jan 16, 2013
Molecular structure, mechanism of fluorescence, and fluorescence spectrum of the optical probe substance for cesium detection.

The NIMS International Center for Materials Nanoarchitectonics (WPI-MANA) has developed a supermolecular material which makes it possible to visualize the distribution of cesium on the surface of solids and in living organisms by fluorescence.

As a result of the accident at the No. 1 following the Great East Japan Earthquake of March 2011, a large amount of leaked and contaminated a wide area. Among those substances, , which is a of cesium, has a long half-life of 30 years, and thus will continue to be a source of radiation in the future. The Japanese government has planned and implemented decontamination measures for the region which was contaminated by radioactive substances. However, if the distribution of cesium can be visualized, this decontamination work can be carried out more efficiently, and a reduction in the amount of contaminated waste generated by the decontamination work can also be expected. At present, research and development of a camera that enables visualization of radioactive substances is being carried out with the cooperation of industry, academia, and government agencies.

This research group developed a fluorescent probe that detects cesium using supermolecular interaction. This optical probe emits green fluorescent light when it contains cesium, thereby enabling visual confirmation of cesium distributed on the surface of a solid. It has higher spatial resolution than the existing methods of detecting radioactive substances, and makes it possible to visualize the distribution of cesium with submillimeter accuracy. The technology for detection of cesium ions, not limited to radioactive isotopes, is expected to compensate for the weaknesses of these existing methods.

When alcohol in which this optical probe has been dissolved is sprayed on soil that contains cesium, and the soil is then irradiated with an ultraviolet light, only the spots that are contaminated with cesium emit green fluorescent light. Because this enables selective removal of only the cesium-contaminated spots, a large reduction in the amount of generated by decontamination work can be expected.

Furthermore, when alcohol in which the optical probe has been dissolved is sprayed on the cross section of the stem of a plant immersed in water that contains cesium, and is then irradiated with an ultraviolet light, only the parts that contain cesium emit green fluorescent light. In other words, a visual understanding of the diffusion behavior and accumulation process of cesium is possible.

The results of this research make it possible to visualize the distribution of cesium with submillimeter accuracy, and thus are expected to make an important contribution to higher efficiency in decontamination work, elucidation of the cesium diffusion and accumulation process, and related issues.

These research results are scheduled for online publication in the January 2013 issue of the scientific journal Science and Technology of Advanced Materials.

Explore further: A new approach to creating organic zeolites

add to favorites email to friend print save as pdf

Related Stories

Mountains limited spread of fallout from Fukushima

Nov 14, 2011

A map of radioactive contamination across Japan from the Fukushima power plant disaster confirms high levels in eastern and northeastern areas but finds much lower levels in the western part of the country, thanks to mountain ...

A Venus flytrap for nuclear waste

Jan 26, 2010

Not every object is food to a Venus flytrap. Like the carnivorous plant, a new material developed at Northwestern University permanently traps only its desired prey, the radioactive ion cesium, and not other harmless ions ...

Study: Japan nuke radiation higher than estimated

Oct 27, 2011

A new report says the Fukushima nuclear disaster released twice as much of a dangerous radioactive substance into the atmosphere as Japanese authorities estimated, reaching 40 percent of the total from Chernobyl.

Radiation detected 400 miles off Japanese coast

Feb 21, 2012

(AP) -- Radioactive contamination from the Fukushima power plant disaster has been detected as far as almost 400 miles off Japan in the Pacific Ocean, with water showing readings of up to 1,000 times more ...

Recommended for you

A new approach to creating organic zeolites

20 hours ago

Yushan Yan, Distinguished Professor of Engineering at the University of Delaware, is known worldwide for using nanomaterials to solve problems in energy engineering, environmental sustainability and electronics.

A tree may have the answers to renewable energy

Jul 23, 2014

Through an energy conversion process that mimics that of a tree, a University of Wisconsin-Madison materials scientist is making strides in renewable energy technologies for producing hydrogen.

User comments : 0