SORIS—A standoff radiation imaging system

The detection of radiological and special nuclear material within the country's borders is a crucial component of the national security network. Being able to detect small amounts of radiological material at large distances is especially important for search applications. To provide this capability General Electric's Research Center has developed, as a part of DNDO's standoff radiation detection system advanced technology demonstration (SORDS-ATD) program, a standoff radiation imaging system (SORIS). This vehicle-based system is capable of detecting weak sources at large distances in relatively short times. To accomplish this, GE has developed a novel coded aperture detector based on commercial components from GE Healthcare. An array of commercial gamma cameras modified to increase the system efficiency and energy range are used as position sensitive detectors. Unlike typical coded aperture systems, however, SORIS employs a non-planar mask and thus does not suffer the typical limitations of partially encoded regions giving it a wide field of view. Source identification is done using both low-statistics anomaly indicators and conventional high-statistics algorithms being developed by Pacific Northwest National Laboratory. The results of scanned areas and threats identified are displayed to the user and overlaid on satellite imagery.     

核爆炸光辐射探测系统分析

从核爆炸光辐射的特点出发,对基于高速CMOS图像采集与处理的核爆炸光辐射探测系统从理论和结构上进行了分析.根据实际需求,采用高速CMOS成像器件作为光电传感器、DSP快速图像处理系统为中心进行系统架构.分析了基于图像处理的核爆炸参数测量原理,并对大气传输造成的光辐射测量误差进行了计算,编写了图像处理的相关算法程序.模拟实验表明,基于图像处理的核爆炸光辐射探测系统能准确探测核爆炸的相关参数如当量、俯仰角和距离,与传统方法相比具有高精度和良好的稳定性和可靠性,具有一定的实用价值.     

Surrogates of plutonium for detection equipment testing

Fight against illicit trafficking of nuclear material relies on the possibility to detect nuclear material concealed in vehicles, people or cargo containers. This is done by equipping and training law enforcement and security staff in border stations or other points of access to strategic places and critical infrastructures with radiation detection equipment.The design, development, testing and evaluation of these instruments ideally require the use of real nuclear material to assess, verify and certify their detection performance. Availability of special nuclear material may be an issue, especially for industry, since only few specialized laboratories are licensed for such material.This paper tries to analyse and describe the possibility to use suitable surrogates that may replace the use of real nuclear material in testing the detection capabilities of instruments used in nuclear security.     

High-$T_{c}$ Josephson Square-Law Detectors and Hilbert Spectroscopy for Security Applications

Among various discussed ways of explosive detection, the techniques using electromagnetic radiation are considered as having great potential and research activities are recommended in this field. To identify new threats, like liquid explosives, with low rate of false alarms, fast spectral measurements are required in a broad frequency range from microwave to terahertz. We attract attention to a great potential of high-T_c Josephson technology in security applications and present our results in developing high-T_c Josephson junctions for Hilbert spectroscopy and detector arrays.     

碘化铅单晶生长及探测器的研究进展

PbI2单晶体是性能优异的室温半导体核辐射探测器新材料。主要介绍了PbI2晶体生长技术及其室温核辐射探测器研究发展的最新动态,综述了PbI2晶体的3种主要生长方法(气相法、熔体法和凝胶法)的原理和优缺点,重点阐述了熔体法生长PbI2晶体的影响因素及研究进展,提出了PbI2单晶制备技术存在的主要问题和今后的发展方向。     

Biological and chemical terrorism

Many different types of potential threats have been identified in the ongoing war against terrorism. Epidemiological threats are not software threats, but perhaps can be better referred to as “soft body” threats. This requires preparedness and response to various kinds of unconventional terrorism, especially biological, chemical, and radiological or nuclear.     

脉冲辐射探测技术

脉冲辐射探测是探知核反应过程特征信息的主要途径之一,是核反应过程特性研究、核装置设计、运行、监测与控制不可或缺的技术手段。由核探测器、探测方法和应用技术等构成的脉冲辐射场探测技术,已成为科学研究、核技术应用、核材料分析、裂变/聚变研究和天体物理等相关核科学研究的必备技术元素。文章介绍了我国发展的瞬态核裂变、核聚变反应过程释放的脉冲中子、伽马混合辐射场探测系统和测量技术。     

Technical performance of the Luxel Al(2)O(3):C optically stimulated luminescence dosemeter element at radiation oncology and nuclear accident dose levels

The dose ranges typical for radiation oncology and nuclear accident dosimetry are on the order of 2-70 Gy and 0.1-5 Gy, respectively. In terms of solid-state passive dosimetry, thermoluminescent (TL) materials historically have been used extensively for these two applications, with silver-halide, leuco-dye and BaFBr:Eu-based films being used on a more limited basis than TL for radiation oncology. This present work provides results on the performance of a film based on an aluminum oxide, Al(2)O(3):C, for these dosimetry applications, using the optically stimulated luminescence (OSL) readout method. There have been few investigations of Al(2)O(3):C performance at radiation oncology and nuclear accident dose levels, and these have included minimal dosimetric and environmental effects information. Based on investigations already published, the authors of this present study determined that overall improvements over film and TLDs for this Al(2)O(3):C OSL technology at radiation oncology and nuclear accident dose levels may include (1) a more tissue-equivalent response to photons compared to X-ray film, (2) higher sensitivity, (3) ability to reread dosemeters and (4) diagnostic capability using small-area imaging. The results of the present investigation indicate that additional favourable performance characteristics for the Al(2)O(3):C dosemeter are a wide dynamic range (0.001-100 Gy), a response insensitive to temperature and moisture over a wide range, negligible dose rate dependence, and minimal change in post-irradiation response. As a radiation detection medium, this OSL phosphor offers an assortment of dosimetry properties that will permit it to compete with current radiation detection technologies such as silver-halide, leuco-dye and photostimulable-phosphor-based films, as well as TLDs.     

Comparison of PVT and NaI(Tl) scintillators for vehicle portal monitor applications

The demand for radiation portal monitor (RPM) systems has increased, and their capabilities are being further scrutinized as they are being applied to the task of detecting nuclear weapons, special nuclear material, and radiation dispersal device materials that could appear at borders. The requirements and constraints on RPM systems deployed at high-volume border crossings are significantly different from those at weapons facilities or steel recycling plants, where RPMs have been historically employed. In this new homeland security application, RPM systems must rapidly detect localized sources of radiation with a very high detection probability and low false-alarm rate, while screening all of the traffic without impeding the flow of commerce. In light of this new Department of Homeland Security application, the capabilities of two popular gamma-ray-detector materials as applied to these needs are re-examined. Both experimental data and computer simulations, together with practical deployment experience, are used to assess currently available polyvinyltoluene and NaI(Tl) gamma-ray detectors for border applications.     

Developing an integrating biological dosimeter for spaceflight

Exposure to harmful radiation is one of the major threats to human beings in outer-space; however, the biological consequences of long term exposure are not well understood. It would be useful to have a means of measuring the effect of space radiation on a living organism during space flights. We conducted a pilot project as part of the International Caenorhabditis elegans Experiment First Flight (ICE-First) project on the International Space Station (ISS). Using a mutational capture system, the eT1 balancer, along with other mutation detection systems, we analyzed the mutational effects of the 11 day mission. Upon recovery, classical genetic approaches and comparative genomic hybridization (CGH) microarrays were used to isolate and characterize mutant strains. Although in this short period of time, as expected no increase in mutational background was observed, we were able to demonstrate the potential of this system for longer-term measurement of biological damage. A sixmonth exposure experiment using the same system is currently in progress on the ISS. The relative simplicity and robustness of this model system demonstrate its potential for use as a biological dosimeter.     

Preliminary dosimetric characterisation of thermoluminescent materials for beta radiation monitoring at nuclear medicine services

Beta emitters are widely used in nuclear medicine for diagnostic and therapeutic purposes. The critical groups exposed to a radioactive patient include the staff, other patients and members of the public accompanying the patient. The aim of this work is to characterise thermoluminescent (TL) materials for the staff monitoring of nuclear medicine services that manipulate beta radiation solutions of (153)Sm. This study was performed using CaSO(4):Dy + Teflon pellets, produced at IPEN, with different dimensions. For the dosimetric characterisation, these TL dosemeters were exposed to gamma source ((60)Co) and to beta sealed sources ((90)Sr + (90)Y, (204)Tl and (147)Pm) and to a non-sealed source ((153)Sm). Results were obtained related to reproducibility, lower detection limits, calibration curves, angle and energy dependence of response. All tested materials show usefulness for monitoring of workers exposed to beta radiation.     

铁电材料的核辐射效应

大量研究结果和实验数据显示,铁电材料与器件具有极强的抗辐射能力,在军事和空间领域具有广阔的应用前景,因此铁电材料及其器件的抗辐射能力与机理研究日益受到关注.首先综述了国内外关于铁电材料的核辐射效应研究最新进展,在此基础上对其核辐射效应微观机理进行了分析和讨论,指出了铁电材料在抗辐射领域的发展趋势和研究方向.     

Rattling nucleons: New developments in active interrogation of special nuclear material

Active interrogation is a vigorous area of research and development due to its promise of offering detection and characterization capabilities of special nuclear material in environments where passive detection fails. The primary value added by active methods is the capability to penetrate shielding—special nuclear material itself, incidental materials, or intentional shielding—and advocates hope that active interrogation will provide a solution to the problem of detecting shielded uranium, which is at present the greatest obstacle to interdiction efforts. The technique also provides a unique benefit for quantifying nuclear material in high background-radiation environments, an area important for nuclear material safeguards and material accountancy. Progress has been made in the field of active interrogation on several fronts, most notably in the arenas of source development, systems integration, and the integration and exploitation of multiple fission and non-fission signatures. But penetration of interrogating radiation often comes at a cost, not only in terms of finance and dose but also in terms of induced backgrounds, system complexity, and extended measurement times (including set up and acquisition). These costs make the calculus for deciding to implement active interrogation more subtle than may be apparent. The purpose of this review is thus to examine existing interrogation methods, compare and contrast their attributes and limitations, and identify missions where active interrogation may hold the most promise.     

A scintillation-solid state detector for a system for the complex monitoring and diagnostics of subcritical electronuclear equipment

A diagnostic instrument in which a combination of a plastic scintillator and a solid-state photomultiplier is used as a nuclear radiation detector, is described. The detector is designed to record x-ray, gamma-ray, and neutron radiation in experimental nuclear power plant.     

Monitoring uranium, hydrogen, and lithium and their isotopes using a compact laser-induced breakdown spectroscopy (LIBS) probe and high-resolution spectrometer

The development of field-deployable instruments to monitor radiological, nuclear, and explosive (RNE) threats is of current interest for a number of assessment needs such as the on-site screening of suspect facilities and nuclear forensics. The presence of uranium and plutonium and radiological materials can be determined through monitoring the elemental emission spectrum using relatively low-resolution spectrometers. In addition, uranium compounds, explosives, and chemicals used in nuclear fuel processing (e.g., tributyl-phosphate) can be identified by applying chemometric analysis to the laser-induced breakdown (LIBS) spectrum recorded by these spectrometers. For nuclear forensic applications, however, isotopes of U and Pu and other elements (e.g., H and Li) must also be determined, requiring higher resolution spectrometers given the small magnitude of the isotope shifts for some of these elements (e.g., 25 pm for U and 13 pm for Pu). High-resolution spectrometers will be preferred for several reasons but these must fit into realistic field-based analysis scenarios. To address the need for field instrumentation, we evaluated a previously developed field-deployable hand-held LIBS interrogation probe combined with two relatively new high-resolution spectrometers (λ/Δλ ~75,000 and ~44,000) that have the potential to meet field-based analysis needs. These spectrometers are significantly smaller and lighter in weight than those previously used for isotopic analysis and one unit can provide simultaneous wide spectral coverage and high resolution in a relatively small package. The LIBS interrogation probe was developed initially for use with low resolution compact spectrometers in a person-portable backpack LIBS instrument. Here we present the results of an evaluation of the LIBS probe combined with a high-resolution spectrometer and demonstrate rapid detection of isotopes of uranium and hydrogen and highly enriched samples of (6)Li and (7)Li.     

Deep Learning-Based Hybrid Intelligent Intrusion Detection System

Machine learning (ML) algorithms are often used to design effective intrusion detection (ID) systems for appropriate mitigation and effective detection of malicious cyber threats at the host and network levels. However, cybersecurity attacks are still increasing. An ID system can play a vital role in detecting such threats. Existing ID systems are unable to detect malicious threats, primarily because they adopt approaches that are based on traditional ML techniques, which are less concerned with the accurate classification and feature selection. Thus, developing an accurate and intelligent ID system is a priority. The main objective of this study was to develop a hybrid intelligent intrusion detection system (HIIDS) to learn crucial features representation efficiently and automatically from massive unlabeled raw network traffic data. Many ID datasets are publicly available to the cybersecurity research community. As such, we used a spark MLlib (machine learning library)-based robust classifier, such as logistic regression (LR), extreme gradient boosting (XGB) was used for anomaly detection, and a state-of-the-art DL, such as a long short-term memory autoencoder (LSTMAE) for misuse attack was used to develop an efficient and HIIDS to detect and classify unpredictable attacks. Our approach utilized LSTM to detect temporal features and an AE to more efficiently detect global features. Therefore, to evaluate the efficacy of our proposed approach, experiments were conducted on a publicly existing dataset, the contemporary real-life ISCX-UNB dataset. The simulation results demonstrate that our proposed spark MLlib and LSTMAE-based HIIDS significantly outperformed existing ID approaches, achieving a high accuracy rate of up to 97.52% for the ISCX-UNB dataset respectively 10-fold cross-validation test. It is quite promising to use our proposed HIIDS in real-world circumstances on a large-scale.     

Experimental and simulated assay of actinides in a real waste package

The non-destructive control of nuclear wastes is important for their management and the non-proliferation. Among the methods using the nuclear radiation as an investigation, the Instrumental Photon Activation Analysis (IPAA) seems to be a promising way to quantify the masses of actinides present in bulky packages of nuclear waste. The IPAA method consists in irradiating actinides with photons of high energy to produce photofission reactions. The counting of the delayed neutrons, produced by these photofission reactions, allows to locate and to quantify the mass of actinides by tomography. At this end, we use a simulation tool named OPERA to obtain the information necessary for the tomographic restitution and an experimental installation based on a LINear ACcelerator (LINAC) to perform the measurements. The high-energy photons (11 MeV) are produced by Bremsstrahlung, thanks to a tungsten target placed in front of the LINAC. In this paper, we present the first experimental results obtained on a real package of nuclear waste. We establish that, for this waste package, the limit of detection, in terms of mass of actinides, is about 1 g. Furthermore, these results show the good agreement between the experiment and the simulation that provides a localization of actinides by tomography.     

核同质异能素的探索性研究

介绍了国外正在研究的第四代核武器关键能源之一核同质异能素的概况。简述了核同质异能素的能量和威力、应用前景,以及核同质异能素的发展原理和所产生的核辐射及杀伤作用。