Tuesday, January 26, 2010

Novel Nanoparticle Scintillation Microdevices for Radiation Detection Unveiled by Louisiana Tech University Researchers

Louisiana Tech University Foundation, Inc. (Ruston, LA) received U.S. Patent 7,652,261 for a radiation detecting device that includes a substantially transparent substrate with one or more transparent scintillating films patterned onto the surface.  The films have integrated waveguides so that radiation of differing species may be detected by an optical light detector and the composition of the radiation may be analyzed.

The multichannel nanoparticle scintillation microdevices with integrated waveguides for radiation detection were developed by Electrical Engineering Assistant Professor Chester S. Wilson and Scott M. Pellegrin. 

Scintillating material for detecting individual species of radiation includes one or more groups of nanoparticles mixed with a fast electron scintillating material.  The material can be extruded into a transparent film such that a light pulse is emitted when said transparent film is exposed to the species of radiation targeted by the nanoparticle groups.

In the four layer device: a first substantially transparent film contains nanoparticles of gadolinium oxide, a second transparent film contains nanoparticles of tungsten oxide, a third transparent film contains nanoparticles of lead oxide, and a fourth film contains nanoparticles of glass.  The four layer device forms a novel fast-electron scintillating material for radiation detection

As illustrated in FIG. 8. the novel scintillating material is comprised of nanoparticles suspended within a commercial scintillating material, such that when extruded into a transparent thin film, the novel scintillating material generates a light pulse upon exposure to radiation. Nanoparticles suspended within the fast-electron scintillating material should produce a sufficiently low scattered light intensity such that the detection of scintillation light from the microdevice is optimized and the scintillating material is substantially transparent. The nanoparticles may be sized from 10-8000 nanometers, such that the diameter of the nanoparticles is smaller than the threshold of scattered light.

FIG. 8 describes generally an embodiment of the novel nanoparticle scintillation material using gadolinium oxide for neutron detection.

The on-chip fusion reaction is graphically illustrated in FIG. 8. In this embodiment, when exposed to neutrons (18), the embedded gadolinium oxide (Gd2O3) nanoparticles (17) within the scintillating resin (21) emit electrons (19). Minimal electron attenuation takes place in the nanoparticle because of its small size. These electrons (19) then scintillate the surrounding matrix (21) and light (27) is emitted from the novel scintillating material.

In another embodiment, additional metal oxide nanoparticles, with high secondary emission coefficients, e.g. tungsten oxide, chrome oxide and the like, in addition to charge conversion nanoparticles of gadolinium oxide, may be added to down-convert fast electrons emitted by the gadolinium oxide nanoparticles into more numerous and less energetic electrons, further confining electrons in the scintillating matrix. This addition of metal oxide nanoparticles allows slow electrons to be more easily adsorbed into the scintillators, minimizing particle leakage and increasing the efficiency of the scintillator.

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