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Intern’s Research Helps ORAU Move Closer to Increasing Its Environmental Assessment Capabilities
Ben Estes recorded field measurements with the ISOCS at ORAU during his summer internship. His work helped ORAU increase its capabilities in radiological assessments and health physics.
The hemlock trees and low humidity of Pennsylvania make Ben Estes long for home, but when given the choice of where to spend his summer; Oak Ridge is the only other place he would rather be.
Estes is no stranger to Oak Ridge Associated Universities (ORAU), having spent the summer of 2005 creating a homemade instrument capable of detecting radiation during his internship with the Independent Environmental Assessment and Verification program.
A recent graduate of Bloomsburg (Pa.) University, Estes returned to ORAU to explore the use of in situ gamma ray spectroscopy (ISGRS)—a technology used to assess levels of radioactive contamination during environmental site surveys.
Estes examined how ISGRS can be used to pinpoint specific areas of radioactive material above and below the soil surface. ISGRS essentially deploys the in situ object counting system (ISOCS) detector—a laboratory-grade instrument—into the field to record detailed information about the radionuclide distribution of contaminants present in real-time.
Gamma rays emitted during the decay of radionuclides are detected in the instrument’s lead-collimated detector. The collimator acts very similarly to an “optical lens,” thereby limiting the field of view. By limiting the ISOCS detector’s field of view, technicians can take readings from a precise area without collecting background gamma radiation from heavily contaminated rooms or nearby sources.
Estes’ research involved evaluating the sensitivity of the ISOCS detector by determining whether it could “see” a small radioactive particle on the fringe of its field of view. The method is similar to peripheral vision testing during an eye exam.
“For a human, it is much like taking a dim pen light and moving it from the front of your eye into your peripheral vision,” he explained. “We were specifically interested in determining at what position the detector would no longer see the particle.”
Estes’ work was important in understanding how adjusting the detector’s spatial resolution can impact the minimum detectable concentration.