Think about ionizing radiation as similar to the shades of color produced by the vast spectrum of light. People with normal vision can see about one million distinct shades. However, those who are color blind see only about five to 10 percent of the shades available.
Anyone limited to only one shade would be regarded as handicapped. Yet, when considering the variety of harmful ionizing radiation potentially present in the workplace environment – alpha particles, beta articles and gamma rays -- most radiation detectors are calibrated to respond accurately to only one radioactive source out of the many that exist.
The result is a tremendous amount of over response or under response to radioactive dose rates, said Scott Masiella, safety and security market manager for Waltham, Mass.-based Thermo Fisher Scientific.
“What that means is sometimes the instrument will tell you that you only have five minutes to stay in a particular region when you could actually stay as long as an hour – and vice versa,” Masiella said.
Thermo Fisher Scientific focuses on developing technology that supports life sciences research, complex analytical challenges, patient diagnostics and laboratory productivity. The company’s chemical analysis division, which includes radiation detection, specializes in turning that technology into tools for uses outside the lab.
“Field ready usually means portable,” Masiella said. “But you still want lab quality results. What our division does is take that technology and make it portable, rugged and field operation capable.”
Thermo Fisher’s RadEye SPRD Detector family is a highly sensitive gamma radiation detection and dose rate measurement tool for security forces, the steel and recycling industry, and first responders trying to detect and locate orphaned sources or problematic NORM (naturally occurring radioactive material) related sources in scrap yards, border crossings and other public locations.
The RadEye SPRD-GN Personal Radiation Detector is the first pager-sized PRD that significantly exceeds the original American National Standards Institute N42-48 2008 standards for neutron alarms.
In a computerized radiation detector, the heart of the device is a scintillator crystal connected to a photomultiplier. RadEye SPRD-GN utilizes a new type of crystal able to identify both gamma rays and neutrons, Masiella said.
“With it we are able to run very specific algorithms that take advantage of the crystal in several ways,” he said.
For example, most competing detectors are dose rate calibrated to only one radioactive source, usually cesium, an isotope with many applications throughout industry. However, calibrating on that one energy source means ignoring all the others, Masiella said.
“Our instrument is calibrated across several isotopes in the energy range of 60keV to 3MeV,” he said. “No matter what isotope has fallen over in the truck, our instrument would be able to report a dose rate that accurately tells how long responders can safely work in the vicinity.”
First responders on the scene would be able to identify exactly what the material is so they can determine how to properly secure it, Masiella said. RadEye SPRD-GN also significantly reduces false alarms.
“About one in a thousand people that responders deal with have had medical treatment recently that can trigger a false alarm,” he said. “RadEye SPRD-GN can help tell the difference between radiation from a medical source and radiation indicating a dirty bomb.”
Detectors giving false alarms is a common problem, particularly in urban landscapes complete with overpasses and underpasses.
“You always run into false alarms with structures containing significant amounts of concrete,” Masiella said. “Materials like granite and marble are naturally radioactive and can change the radioactive signature in the background.”
To deal with the issue, operators are forced to set alarm thresholds higher, increasing the chance that some hidden source of radiation will go undetected, Masiella said.
“Now we have technology that can instantaneously determine whether any change in the background is from a natural or artificial source, significantly reducing false alarms,” he said.
Twenty years ago technology that sensitive required an instrument the size of a large lunch box. Today, Thermo Fisher is the first to shrink a detector down to the size of a cell phone, Masiella said. Also, the RadEye SPRD-GN is significantly easier to operate than previous detectors. “
The detector guides the user through the process of determining if the radiation source is natural or artificial,” Masiella said. “If it’s artificial, it will go ahead and identify exactly what it is and tell you what to do next.”
Also simplified is the process of calibrating and updating the detectors, he said. For most radiation detectors this means shipping the unit back to the manufacturer.
“With our instrument, unless you want to do high range dose rate verifications, you never have to send it back,” he said. “We have a calibration routine that uses natural Lutetium oxide (Lu2 O3), which is naturally radioactive, like kitty litter or bananas.”
An adapter that mounts on the back of the RadEye automatically runs the routine and calibrates the instrument. As with the detector itself, the adapter leads the operator through the calibration program.”
“It only takes about two minutes,” Masiella said.
At present, RadEye units are deployed worldwide, including the Fire Department of New York with 3,500 units and Another 3,000 are in use in the metro Washington, D.C. area, Masiella said. As many as 100,000 RadEye are in use worldwide. The RadEye SPRD-GN, released late in 2016, already has a significant customer base, including Metro Washington DC, Houston Bomb Squad, and Jacksonville FL Fire and Rescue.
Still, there are many cities without this technology or without any radiation detection capability at all, Masiella said.
“While the vast majority of these detectors are sold to government agencies, our next biggest customers are scrap yards and hospitals,” he said. “They want them for same reason everyone else does – to detect and identify radiation where it’s not supposed to be.”