The Gamma and the Beta

By Lee Anna Sherman

Fast, accurate, affordable detection of radiation — whether it’s from Japan’s damaged Fukushima plant, long-buried waste at Hanford’s WWII weapons site, or secret underground testing by rogue nations — is a pressing need internationally.

Abi Farsoni, right, and his graduate student, Abdulsalam Alhawsawi, discuss gamma and beta radiation waves visible on a computer screen. On the desk is the detector developed by Farsoni and colleague David Hamby. (Photo: Karl Maasdam)
Abi Farsoni, right, and his graduate student, Abdulsalam Alhawsawi, discuss gamma and beta radiation waves visible on a computer screen. On the desk is the detector developed by Farsoni and colleague David Hamby. (Photo: Karl Maasdam)

Now, detection technology has taken a notable leap forward. A newly patented invention from Oregon State University uses “phoswich” technology (short for “phosphor sandwich spectrometer”) to detect both beta particles and gamma rays simultaneously. Texas-based firm Ludlum Measurements has signed a contract with OSU’s Department of Nuclear Engineering and Radiation Health Physics to produce two of the detectors for engineering giant CH2M Hill to use in its Hanford cleanup project in Washington, where the U.S. government is spending hundreds of millions of dollars to remove radioactive soil. Ludlum also has expressed interest in licensing the detector for commercial production and sale.

Eventually, the detector may find applications in nuclear energy and medicine, according to David Hamby and Abi Farsoni, professors in nuclear engineering, who developed the device with funding from the U.S. Department of Energy.

A Corvallis-based spinoff called Avicenna Instruments soon will begin production of the device’s electronic components. The fledgling company sees a ready market for the new technology in universities and laboratories, which currently make do with outdated analog equipment. “Detection systems that use digital spectrometers are more reliable, efficient and intelligent,” says Farsoni.

Besides being an important advance on earlier technologies that measured only one type of radiation at a time, the device can be linked to a PC via a simple USB port, the researcher says.

Hot Lines

To demonstrate, he fires up his computer and points to a bright red line pulsating across the screen. The line, which resembles the reading on a heart monitor, indicates background radiation, the levels that occur naturally in the environment. Then, picking up a nickel-sized capsule from the table, he holds it close to the detector. The red line reacts immediately. “See how the waves are going faster and faster?” he says. “This is a gamma source. It emits only gamma rays.” Then, holding up a second capsule to the device, he says, “This is a beta source. See how the shape of the beta pulses is totally different from the gamma pulses?

“With this new system,” the researcher explains, “there’s very little ‘cross talk,’ or interference, between the two types of radiation. It’s very easy to separate the pulses.”

Another plus: Test results can be processed at warp speed. The device, which runs on a small battery, takes a sample every five nanoseconds, giving users 1,000 samples in five microseconds, according to Farsoni. These mega-fast results can then go global instantly on the Internet.

“Now I can email pulses to my friends in India or Europe,” Farsoni says.

Adds Hamby: “This system will be able to provide accurate results in 15 minutes that previously might have taken half a day. That saves steps, time and money.”

Using MATLAB (a technical computing language and interactive environment for algorithm development, data visualization, data analysis, and numeric computation), users can quickly and easily change algorithms in the coding to customize the device for specific detection needs.

“You can reprogram it any time you want,” says Farsoni.

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