Time-resolved gamma-ray spectroscopy with the GEARS detector: Applications in environmental radionuclide monitoring and neutron activation analysis

The Simon Fraser University Nuclear Science Laboratory (SFU NSL) joined into two collaborations, each with an interest in monitoring Fukushima-derived cesium-134 and cesium-137 in various environmental samples. The first investigated Fukushima-derived contamination in soil and three species of Pacific salmon, sockeye, chum, and Chinook. The second investigated Fukushima-derived contamination in sockeye salmon, Dungeness crab, and kelp. In both of these monitoring campaigns, the maximum radiocesium activity concentrations observed were significantly below Health Canada's regulatory limits with the conclusion drawn that there is no health risk to the average Canadian seafood consumer. The Neutron Generator Facility at SFU NSL has recently acquired a Thermo Scientific P 385 neutron generator capable of activating samples, inducing radioactivity in them which may be studied via time-resolved gamma-ray spectroscopy. Recording timing information is a prerequisite of these studies therefore, a new data acquisition (DAQ) system was installed with the Germanium detector for Elemental Analysis and Radioactivity Studies enabling timing measurements to take place. The new DAQ system was benchmarked via the measurement of two neutron activated metals, verifying its stability and precision.