Woodruff School of Mechanical Engineering

NRE/MP Seminar

Nuclear & Radiological Engineering and Medical Physics Programs


Two-timing and double-dealing in real-time assay of mixed radiation fields


Dr. Malcolm Joyce


, Lancaster University, United Kingdom


Thursday, October 26, 2017 at 11:00:00 AM


Boggs Building, Room Room 3-47


Anna Erickson


While a variety of radiation detectors are known to exhibit a response to more than one type of radiation at the same time, relatively few detectors can yield really useful information unless the interfering radiation is excluded to clean up the response. Conversely, where a range of information is required from a number of different radiations, often more than one type of detector is used instead. Organic scintillation detectors are perhaps a little different because, prior to pulse-shape discrimination, events spawned by different types of ionizing radiation (usually fast neutrons and -ray photons) are very similar; in the digital domain they constitute a pulse train that can be processed in a manner that is identical, irrespective of their physical character. This is often accomplished via established a first-in, first-out buffer processing with the implicit benefit that no time lag arises that is dependent on the specific type of radiation. Consequently, mixed radiation fields that are typical in nuclear engineering applications, such as from reactors, sources, spent fuel, plutonium assay and active assay of uranium enrichment, can be investigated via both components of the field with the advantage that the coincidence signature of both the neutrons and  rays is preserved. This enables multiplicity assay, interval time distributions, real-time imaging, tomography and spectroscopy of the mixed field, rather than a specific component of it. In this seminar, several examples of these approaches will be described and the prospects for the future will be summarized.


Malcolm Joyce is Professor of Nuclear Engineering at Lancaster University in the UK. His research interests include applied radiation detection & measurement, decommissioning-related analytical methods and nuclear policy & environmental assay. He is author on > 140 refereed journal articles and has specialized of late in digital mixed-field radiation assay with fast, organic liquid scintillation detectors. Malcolm has a BSc (Hons.) in physics, a PhD in -ray spectroscopy and a DEng in digital fast neutron assay. He was a member of the UK Government's Nuclear Industry Research Advisory Board (NIRAB) and is co-chair of UK’s National Nuclear Users' Facility (www.nnuf.ac.uk). In 2014 his team were awarded the James Watt medal by the Institution of Civil Engineers (www.ice.org.uk) for best paper in the journal Proc. ICE (Energy) for research on the depth profiling of radioactive contamination in concrete. In 2016 he was awarded a Royal Society Wolfson Research Merit Award.


Refreshments will be served.