Beta Fiber-Optic-Sensor for Detecting Strontium-90 and Uranium-238 in Soil

Category: Characterization > Sampling & Analysis Equipments > Analysis Equipment
Reference # : OST No 70, DOE/EM-0424 Model No : BetaScint TM

The BetaScint(TM) sensor is designed to measure beta emissions from Sr-90 and U-238 in soils. The sensor is 150x35x8cm; it can measure contamination of the soil surface or of a soil sample spread over a tray. The time required is 20 minutes per sample at a cost of $30-55, compared with 1-4 weeks and $150-275 for laboratory analyses. The BetaScint sensor works as follows: (1) beta particles (electrons) emitted by radioactive soil contaminants excite electrons in fluorescent compounds doped into plastic fibers in the layers of the sensor; (2) these give off light (scintillate) when the fluorescent molecules lose energy and return to their ground state; (3) scintillations are counted by photodetectors to determine beta radioactivity of the soil sample. Sample processing is limited to drying and sieving soil samples to remove rocks and excessive organic matter. The BetaScint system is easy to operate and does not generate secondary wastes.

Benefits

Cost savings of 60%-90% per sample. Near-real-time analyses, compared with 1-5 weeks for off-site laboratory analyses. Avoidance of costs associated with unnecessary excavation of uncontaminated soils. Avoidance of secondary waste generation.

Limitations

It is specifically designed to measure beta radiation from Sr-90 and U-238. If other radionuclides are known (or suspected) to be present, the BetaScint TM sensor must be supplemented with other measurement techniques such as the germanium detector used to measure Ra-226 contamination atLEHR. · The BetaScint TM sensor cannot distinguish between beta radiation from Sr-90 and U-238, so it actually measures total (Sr-90 + U-238) contamination. However, except in rare cases such as the contamination found at the Chernobyl site in Ukraine Sr-90 and U-238 usually do not occur together in contaminated soils because Sr-90 is a fission product and U-238 is a raw material for nuclear processes.

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	BetaScint Fiber-Optic Sensor
	BetaScint

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