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G. S. Nusinovich - One of the best experts on this subject based on the ideXlab platform.
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Remote Detection of Concealed Radioactive Materials by Using Focused Powerful Terahertz Radiation
Journal of Infrared Millimeter and Terahertz Waves, 2016Co-Authors: G. S. NusinovichAbstract:This review paper summarizes the results of studies of a novel concept of the remote detection of concealed Radioactive Materials by using focused high-power terahertz (THz) radiation. The concept is based on the known fact that the ambient electron density in air is low (one to three free electrons per cubic centimeter). These electrons can serve as seed electrons from which an avalanche breakdown in strong electromagnetic fields starts. When a powerful THz radiation is focused in a small spot, the breakdown-prone volume can be much smaller than a cubic centimeter. So, the probability of having some free electrons in this volume and, hence, the probability of breakdown are low in the absence of additional sources of air ionization. However, in the vicinity of Radioactive Materials (10–20 m), the electron density can be higher, and, hence, there are always some seed free electrons from which the avalanche ionization will start. Thus, the breakdown rate in this case can be close to 100 %. Realization of this concept requires studies of various physical and technical issues. First, it is necessary to develop a high-power source of (sub-) THz radiation whose power, frequency, and pulse duration are sufficient for realizing this goal. Second, it is necessary to analyze numerous issues important for realizing this concept. Among these issues are (a) enhancement of the ionization level of air molecules in the presence of hidden Radioactive Materials, (b) estimating the minimum detectable mass of Radioactive material, (c) formation of breakdown-prone volumes in focused THz wave beams, and (d) effect of atmospheric conditions on the propagation and focusing of THz wave beams and on the optimal location of the breakdown-prone volume between a container with hidden Radioactive material and a THz antenna. The results of these studies are described below.
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The concept of remote detection of concealed Radioactive Materials by using high-power THz radiation
2013 38th International Conference on Infrared Millimeter and Terahertz Waves (IRMMW-THz), 2013Co-Authors: G. S. Nusinovich, M. Glyavin, A. G. LuchininAbstract:This paper describes the progress in developing a high-power, sub-THz gyrotron with a pulsed solenoid and new results in elaborating the concept of THz gyrotron radiation for remote detection of concealed Radioactive Materials. The 0.67 THz gyrotron delivers more than 200 kW in 20-30 microsecond pulses and operates with the efficiency about 20%. New contributions to the development of the concept include: a) analysis of the propagation of gamma rays and production of free electrons in air, b) estimating the mass of Radioactive material which can be detectable at a certain distance from the source, c) characterization of the breakdown-prone volume as the function of the THz power and polarization, crossing angles (in the case of crossing wave beams) and the atmospheric turbulence.
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Remote detection of Radioactive Materials using a near-terahertz gyrotron
2012 Abstracts IEEE International Conference on Plasma Science, 2012Co-Authors: V. Granatstein, G. S. Nusinovich, P Sprangle, J. Rodgers, C.a. Romero-talamas, R. Pu, D. Kashyn, A. ShkvarunetsAbstract:Summary form only given. We are studying new concepts for remote detection of concealed Radioactive Materials. The research is a balanced effort consisting of theory, simulations and experiments. Radioactive Materials emit gamma rays which ionize the surrounding air. High energy free electrons produced by the gamma rays rapidly participate in subsequent ionization events producing a cascade of secondary electrons with temperatures down to thermal level (less than 1 eV). Such thermal electrons attach to oxygen molecules in ~10 nanoseconds forming negative O2- ions. In the vicinity of Radioactive material, the densities of negative ions can be greatly elevated compared to the background (ambient) levels. For example, one gram of cobalt-60 can increase the density of negative ions at a distance of 4 meters by several thousand times. The extra electrons on the negative oxygen ions will be detached by collisions after a lag time (~1 microsecond) . When a free electrons is released into a focused high-power near-THz wave beam an avalanche breakdown of the air can be initiated resulting in an exponential rise in electron density and spark formation. The lag time delay for spark formation is a function of negative ion density and therefore provides a means for detecting the presence of concealed Radioactive material. This scheme can be realized with a standoff range up to 100 m using a near-terahertz source with peak power of 200 kW and pulse duration on the order of 10 microseconds. We are developing a 670 GHz gyrotron oscillator to study the air breakdown phenomenon in the presence of negative ions and aerosols. Initial operation of a 670 GHz gyrotron with a 28 T pulsed solenoid produced a power at about the 80 kW level in a 7 microsecond pulse. These experiments are in progress.
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on the sensitivity of terahertz gyrotron based systems for remote detection of concealed Radioactive Materials
Journal of Applied Physics, 2012Co-Authors: G. S. Nusinovich, P Sprangle, V E Semenov, D S Dorozhkina, Yu M. GlyavinAbstract:This paper analyzes some features of systems intended to remotely detect concealed Radioactive Materials by using a focused THz radiation. This concept is based on possibility to focus high-power THz radiation in a small spot where the wave field exceeds the breakdown threshold. However, in the absence of any sources of ionization, the probability to have in this breakdown-prone volume any seed electrons is very low. Thus, high breakdown rate in a series of THz pulses will indicate the presence of concealed Radioactive Materials in the vicinity of a focused wave beam. The goal of the present paper is to determine by using the statistical theory THz pulse duration required for reliable initiation of the discharge. Then, the detectable mass of the Radioactive material is determined as the function of distance and of the THz wave power and pulse duration. Lastly, possible benefits from using pulse compressors, which shorten the pulse duration but increase the wave power and, hence, the breakdown-prone volume...
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Experimental program to test a high-power, 670 GHz gyrotron, and its applicability to the remote detection of concealed Radioactive Materials
IVEC 2012, 2012Co-Authors: Carlos A. Romero-talamás, G. S. Nusinovich, Victor L. Granatstein, John C. Rodgers, Dmytro Kashyn, Brian Lenardo, Raymond C. Elton, Anatoly Shkvarunets, M. GlyavinAbstract:Tests planned to validate the operation of a 300 kW, 670 GHz gyrotron, presently under construction at the University of Maryland, are presented. Once the gyrotron is operational, the program will focus on investigating the applicability of the gyrotron's wave beam to remotely detect the presence of concealed Radioactive Materials.
Yu M. Glyavin - One of the best experts on this subject based on the ideXlab platform.
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on the sensitivity of terahertz gyrotron based systems for remote detection of concealed Radioactive Materials
Journal of Applied Physics, 2012Co-Authors: G. S. Nusinovich, P Sprangle, V E Semenov, D S Dorozhkina, Yu M. GlyavinAbstract:This paper analyzes some features of systems intended to remotely detect concealed Radioactive Materials by using a focused THz radiation. This concept is based on possibility to focus high-power THz radiation in a small spot where the wave field exceeds the breakdown threshold. However, in the absence of any sources of ionization, the probability to have in this breakdown-prone volume any seed electrons is very low. Thus, high breakdown rate in a series of THz pulses will indicate the presence of concealed Radioactive Materials in the vicinity of a focused wave beam. The goal of the present paper is to determine by using the statistical theory THz pulse duration required for reliable initiation of the discharge. Then, the detectable mass of the Radioactive material is determined as the function of distance and of the THz wave power and pulse duration. Lastly, possible benefits from using pulse compressors, which shorten the pulse duration but increase the wave power and, hence, the breakdown-prone volume...
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Development of THZ-range gyrotrons for detection of concealed Radioactive Materials
2011 21st International Crimean Conference "Microwave & Telecommunication Technology", 2011Co-Authors: Yu M. Glyavin, A. G. Luchinin, M. V. Morozkin, A. S. Sedov, G. S. NusinovichAbstract:The design of 0.67 THz/200 kW pulsed gyrotron for detecting concealed Radioactive Materials is presented. The coil with liquid nitrogen cooling and solenoid power supply was successfully tested.
Nicolas H. Younan - One of the best experts on this subject based on the ideXlab platform.
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Optimized Spectral Transformation for Detection and Classification of Buried Radioactive Materials
IEEE Transactions on Nuclear Science, 2012Co-Authors: Qian Du, Nicolas H. YounanAbstract:We investigate the detection and classification of buried Radioactive Materials of interest using data collected by a sodium iodide (NaI) detector with a short sensor dwell time (i.e., less than or equal to 1 s). The objective of detection is to detect a target from background and nontarget Materials, while the objective of classification is to classify targets buried at different depths. Binned energy windows can reduce data dimensionality, help alleviate the negative impact from background, and suppress trivial spectral variations. However, the performance is sensitive to bin partition parameters including the number of bins and their bin widths. We have developed a particle swarm optimization (PSO)-based automatic system to determine these parameters. We also propose to apply a multiobjective PSO to optimize both the detection and classification accuracy simultaneously. The experimental results show that the PSO-based algorithm can outperform the Powell's direction set optimization method. The multiobjective PSO can achieve the balance between the two objectives, and it may provide even better individual accuracy than a single-objective PSO.
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Parallel optimization-based spectral transformation for detection and classification of buried Radioactive Materials
2011 IEEE Nuclear Science Symposium Conference Record, 2011Co-Authors: Qian Du, Nicolas H. YounanAbstract:In this paper, we investigate detection and classification of buried Radioactive Materials of interest using data collected by a Sodium Iodide (NaI) detector with short sensor dwell time (i.e., less than or equal to 1 s). Due to the sparseness and randomness of a gamma spectrum, four different spectral transforms are implemented as mechanisms for background normalization and feature extraction. These spectral transforms are based on binned energy windows determined by a particle swarm optimization (PSO) method. However, the overall process is time-consuming. Since parallel computation is an appropriate approach to reduce the computation burden of the PSO-based search process, the parallel implementation on cluster for optimal bin partition is proposed in this paper. The speedup performance and resulting detection and classification performance are investigated.
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Estimation of mass and depth of buried Radioactive Materials using neural networks
IEEE Nuclear Science Symposuim & Medical Imaging Conference, 2010Co-Authors: Qian Du, Nicolas H. YounanAbstract:In this paper, we investigate the use of a backpropagation neural network (BPNN) to estimate the mass and depth of buried Radioactive Materials, i.e., depleted uranium (DU). A Lanthanum bromide(LaBr) detector is employed to collect the data for buried targets with different mass and at different depths. Due to the sparseness and randomness of a gamma spectrum, spectral transformation methods are implemented for background normalization and feature extraction. These spectral transformations are based on various binned energy windows determined by the particle swarm optimization (PSO) approach. The transformed data will be used as the inputs to BPNN. Compared with the original spectra, principle component analysis (PCA)-transformed spectra, and uniformly partitioned spectra, the optimized spectral transformed data can provide more accurate estimates.
Nicholas H. Younan - One of the best experts on this subject based on the ideXlab platform.
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Detection of Radioactive Materials using surface proximity antennas
2011 XXXth URSI General Assembly and Scientific Symposium, 2011Co-Authors: Erdem Topsakal, Tutku Karacolak, Nicholas H. YounanAbstract:The objective of this study is to detect and identify Radioactive Materials using surface proximity antennas. To do so, we first developed a simulation model of earth as seen in Fig 1a. We have then designed microstrip patch antennas propagating (-z-direction) towards earth surface to understand the effects of earth and buried objects on the antenna performance (Fig. 1b). Various types of objects (pec, Radioactive Materials, glass, etc.) were placed at different depths and simulations were carried out to detect changes in antenna parameters such as return loss. It was seen that buried objects does affect the antenna performance changing with the type of the object. We have searched for frequencies in the spectrum and considered antenna array systems to increase the detectability of the problem. Figure 2a shows the antenna return loss comparison for three different cases; a) without the object, b) object located right beneath the surface, and c) object located 20cm beneath the surface. In Figure 2b, we present electric field distribution. The hot spot represents the region where the object is located. At the time of the presentation, we will provide antenna design details, and simulation results for various antenna topologies and operating frequencies.
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Detection of Radioactive Materials using surface proximity antennas
2011 XXXth URSI General Assembly and Scientific Symposium, 2011Co-Authors: Erdem Topsakal, Tutku Karacolak, Nicholas H. YounanAbstract:Summary form only given. The objective of this study is to detect and identify Radioactive Materials using surface proximity antennas. To do so, we first developed a simulation model of earth as seen in Fig 1a. We have then designed microstrip patch antennas propagating (-z-direction) towards earth surface to understand the effects of earth and buried objects on the antenna performance (Fig. 1b). Various types of objects (pec, Radioactive Materials, glass, etc.) were placed at different depths and simulations were carried out to detect changes in antenna parameters such as return loss. It was seen that buried objects does affect the antenna performance changing with the type of the object. We have searched for frequencies in the spectrum and considered antenna array systems to increase the detectability of the problem. Figure 2a shows the antenna return loss comparison for three different cases; a) without the object, b) object located right beneath the surface, and c) object located 20cm beneath the surface. In Figure 2b, we present electric field distribution. The hot spot represents the region where the object is located. At the time of the presentation, we will provide antenna design details, and simulation results for various antenna topologies and operating frequencies.
L.b. Shappert - One of the best experts on this subject based on the ideXlab platform.
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Completion of the Radioactive Materials Packaging Handbook
1998Co-Authors: L.b. ShappertAbstract:The Radioactive Materials Packaging Handbook: Design, Operation and Maintenance, which will serve as a replacement for the Cask Designers Guide (Shappert, 1970), has now been completed and submitted to the Oak Ridge National Laboratory (ORNL) electronics publishing group for layout and printing; it is scheduled to be printed in late spring 1998. The Handbook, written by experts in their particular fields, is a compilation of technical chapters that address the design aspects of a package intended for transporting Radioactive material in normal commerce; it was prepared under the direction of M. E. Wangler of the US Department of Energy (DOE) and is intended to provide a wealth of technical guidance that will give designers a better understanding of the regulatory approval process, preferences of regulators on specific aspects of package design, and the types of analyses that should be considered when designing a package to carry Radioactive Materials.
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The Radioactive Materials Packaging Handbook: an overview
International Journal of Radioactive Materials Transport, 1998Co-Authors: L.b. ShappertAbstract:Abstract The Radioactive Materials Packaging Handbook provides information on the design, operation, and maintenance of shipping packages. The 500-page document was published in June 1998 and will serve as a replacement for the Cask Designers Guide. The Handbook, written by experts in their particular fields, is a compilation of technical chapters that address the design aspects of a package intended for transporting Radioactive material in normal commerce; it was prepared under the direction of M. E. Wangler of the US Department of Energy (DOE) and provides a wealth of technical guidance that gives designers a better understanding of the regulatory approval process, preferences of regulators on specific aspects of package design, and the types of analyses to be considered when designing a package to carry Radioactive Materials. Even though the Handbook is concerned with both small and large packagings, most of the emphasis is placed on large packagings that are capable of transporting fissile, radioactiv...
