According to the International Atomic Energy Agency (IAEA), which tracks incidents of illicit or unauthorized uses of nuclear and radioactive materials in participating member states, there were 189 incidents reported in 2019 alone. These materials could potentially be used by terrorists in a radiological dispersal device intended to explode and spread materials over a large area. Because of this threat, monitoring systems are installed at ports and other border crossings to detect the trafficking of nuclear and other radioactive materials. These systems alert personnel when possible illicit materials come through checkpoints.
Linda Anuar is a Ph.D. student working with Center for Nuclear Security Science and Policy Initiatives (NSSPI) Deputy Director Dr. Craig Marianno. She is working on a new method using compressed sensing principles that could provide an easy and cost-effective secondary monitoring system that personnel could use at border crossings to evaluate cases in which the primary monitoring system alarms.
According to Anuar, “Secondary monitoring systems are important in helping personnel to make the decision on how to handle the suspected radioactive source, especially when the shape of the radioactive material can be determined.”
There are a very limited number of studies on compressed sensing techniques applied to radiation source imaging systems for nuclear security purposes. Anuar’s research incorporated compressed sensing principles, which are typically used in signal processing, to the physical design of a gamma source imaging system. Compressed sensing applications have been shown to allow for a much lower number of measurements needed for image reconstruction compared to the conventional raster scanning method. She performed computer simulations and experimental measurements of the proposed design to obtain count data for 50 collimator configurations. Her simple and inexpensive proof-of-concept system, which utilizes easily available Geiger Muller detectors for count measurements, was able to accurately locate gamma point sources with as low as 10% of the required number of measurements needed in the raster scanning method.
For Anuar, the results of this research show that it is possible to develop an effective system that is accessible even to countries with limited monitoring budgets. “The proposed idea of integrating compressed sensing principles to imaging systems contributes to the diversification of counterterrorism tools,” she said. “Additionally, the potential use of affordable radiation detectors demonstrated in my research paves a way for technology transfer to economically-challenged countries” and “promotes technology transfer to strengthen global nuclear security initiatives.”
Anuar successfully defended her dissertation on this research and will be graduating with a Ph.D. in nuclear engineering in December 2021. She also completed the Graduate Certificate in Nuclear Security. Anuar received her Bachelor of Engineering in Engineering Physics from McMaster University in Canada in 2011 and her Master of Science in Nuclear Power Plant Engineering from KEPCO International Nuclear Graduate School in South Korea in 2014. She worked as a lecturer at the Malaysian Universiti Tenaga Nasional (National Energy University) in the Mechanical Engineering Department from 2014 to 2016 before joining NSSPI, and she will return to serve there again upon graduation.
During her time at NSSPI, Anuar was able to travel to Japan as part of the International Nuclear Facilities Experience (INFE), which included a very poignant visit to the Hiroshima Peace Memorial Museum and a talk by a survivor of the bombing, as well as visits to reprocessing facilities and the Fukushima Daiichi Nuclear Power Station. She also participated in hands-on safeguards workshops at both Oak Ridge and Los Alamos National Laboratories. She served as a graduate teaching fellow for undergraduate radiation detection courses and as a committee member of the Texas A&M INNM Student Chapter.
“My experiences with NSSPI have provided me with greater insight into the complex dilemma that surrounds the use and safeguarding of nuclear technologies,” reflected Anuar. “I believe that my experiences here will support my role as an educator in facilitating the younger generation to better understand nuclear technologies, applications, and ethics.”