Speaker
Description
Particle discrimination is a valuable imaging detector capability for applications such as medical physics, environmental monitoring, decontamination, and nuclear forensics. Across these areas, samples can have complex matrices, and a large range of radioactivity levels, which present analysis and measurement challenges for digital autoradiography systems (e.g., knowing how long to measure and how to optimize acquisition parameters for different particle types a priori). Digital autoradiography with an ionizing-radiation Quantum Imaging Detector (iQID) records the location and time of individual scintillation events can overcome these challenges with real-time, enhanced particle discrimination capabilities.
The iQID is a scintillation-based imaging system that uses an image intensifier, lens, and a complementary metal-oxide- semiconductor (CMOS) camera. The iQID collects list mode data which contains information about the morphology of each individual scintillation flash. The list mode data is used to create images with various parameter cuts, such as event size, intensity, time, and shape. In its current operating modes, the detector can perform alpha or beta particle imaging which is mostly achieved by the choice of scintillator. Simultaneous dual particle imaging would streamline sample analysis, removing the need to swap scintillators and reducing measurement times.
A dual particle sensitive alpha/beta composite scintillator (ZnS:Ag with Gadox backing Qscint Imaging Solutions, LLC) was used to measure alpha and beta emitting sources separately to gather list mode data while maintaining all other acquisition parameters constant. Post processing focused on event cluster intensity, area, eccentricity to determine differences between alpha and beta scintillation events. A dual particle measurement took place where the alpha and beta emitting sources were physically separated and in post processing, the differences were utilized to determine whether each event was from an alpha source or a beta source. Leveraging the morphological differences in the scintillation events creates accurate radiological map in which multiple emission types can be represented from a single autoradiographic measurement.
The authors acknowledge funding from the following funding sources. This material is based upon work supported in part by the Consortium for Nuclear Forensics under Department of Energy, National Nuclear Security Administration award number DE-NA0004142. Kyle C. Hartig is supported in part by the Defense Threat Reduction Agency under the award number HDTRA1-20-2-0002. Ben McDonald and Hannah Patz are supported in part by the Pacific Northwest National Laboratory (PNNL) Laboratory Directed Research and Development Program Nuclear Forensics Transformational Innovation (NFTI) Initiative. PNNL is a multiprogram national laboratory operated by Battelle for the Department of Energy under Contract No. DE-AC05-76RLO 1830. PNNL Release Number: PNNL-SA-221700