2
Indications and Warning Technologies

INTRODUCTION

Within the Army homeland security (HLS) framework, indications and warning (I and W) would be classed as a pre-event undertaking. I and W generally refers to the ability to detect events leading up to an attack. These events might involve enemy planning of the attack, its identification of targets of the attack, its acquisition of materials needed for the attack, its positioning of materials to carry out the attack, and, finally, its launch of the attack itself. Much of this is the province of the intelligence community within the civilian sector rather than of the Deputy Assistant Secretary of the Army for Science and Technology (DASA (S&T)). However, as materiel is moved so as to become an imminent threat to the Army, the science and technology (S&T) necessary to allow the Army to detect the presence of this material or its movement is the legitimate responsibility of DASA (R&T), as is the S&T associated with detecting the launch of the attack itself. In some cases the S&T resources necessary to meet these responsibilities reside with other agencies.

Since the Army will have a significant role in responding to any use of weapons of mass destruction (WMD),1 this study focused on the physical detection of or the movement of explosives (nuclear and conventional), radioisotopes, chemical agents, and/or biological agents and the identification of related S&T, which is cross-cutting in character. The Army is responsible for defending its own forces at home and abroad and will need to acquire the technology to do so

1  

The important topic of I and W in cyberspace was not addressed due to the short duration of the study.



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Science and Technology for Army Homeland Security: Report 1 2 Indications and Warning Technologies INTRODUCTION Within the Army homeland security (HLS) framework, indications and warning (I and W) would be classed as a pre-event undertaking. I and W generally refers to the ability to detect events leading up to an attack. These events might involve enemy planning of the attack, its identification of targets of the attack, its acquisition of materials needed for the attack, its positioning of materials to carry out the attack, and, finally, its launch of the attack itself. Much of this is the province of the intelligence community within the civilian sector rather than of the Deputy Assistant Secretary of the Army for Science and Technology (DASA (S&T)). However, as materiel is moved so as to become an imminent threat to the Army, the science and technology (S&T) necessary to allow the Army to detect the presence of this material or its movement is the legitimate responsibility of DASA (R&T), as is the S&T associated with detecting the launch of the attack itself. In some cases the S&T resources necessary to meet these responsibilities reside with other agencies. Since the Army will have a significant role in responding to any use of weapons of mass destruction (WMD),1 this study focused on the physical detection of or the movement of explosives (nuclear and conventional), radioisotopes, chemical agents, and/or biological agents and the identification of related S&T, which is cross-cutting in character. The Army is responsible for defending its own forces at home and abroad and will need to acquire the technology to do so 1   The important topic of I and W in cyberspace was not addressed due to the short duration of the study.

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Science and Technology for Army Homeland Security: Report 1 regardless of which agency is responsible for the development of that technology. For this reason, in the summary charts that follow some areas that are designated as very important to the Objective Force and to HLS are nonetheless assigned a low priority for the use of Army S&T funds. This does not necessarily mean that the expenditure of S&T funds for these areas has a low priority; rather, it often means that organizations other than the Army are responsible for the required S&T investments.2 The committee found cross-cutting technologies3 such as the networking of distributed sensors, data fusion and advanced materials that are strong contenders for Army S&T and that would also be of great benefit to the WMD detection problem. The traditional I and W for threats to Army facilities have also been considered briefly. In many cases the current imaging sensors and other perimeter systems may be adequate as available; in other cases they are being improved through research and development (R&D). Signature analysis for terrorist activities is a very difficult problem from a purely S&T point of view. However, gains may be possible by using some of the cross-cutting technologies. Examples include face recognition algorithms embedded in image sensor processors. Alternatively, more complex processing could be embedded in sensors that are designed to dramatically enhance performance by drawing on novel bioinspired architectures and on large databases of known terrorists. The committee did not include the acoustic, seismic, and radio frequency (RF) sensors used for perimeter defense in this chapter, but it discusses them in other chapters. The remainder of this section briefly summarizes technologies for detecting nuclear weapons and radioisotopes, conventional explosives, chemical agents, and biological agents, along with the relevant cross-cutting technologies. The study was of short duration, and the committee does not claim completeness. The scope of the S&T covered by this study is so broad that a complete analysis would be a massive undertaking. The approach was to illustrate the types of technology employed and the various stages of development by using a number of examples. SENSOR TECHNOLOGIES Traditional Imaging Sensors The committee first mentions the advanced, high-performance imaging systems that infuse all aspects of national security and defense and also have rel- 2   For example, the S&T for the detection of nuclear weapons is principally a Department of Energy responsibility, with some responsibility assigned to the Defense Threat Reduction Agency. In another example the appropriations for funding the S&T related to the detection of chemical agents and biological agents have been assigned to the Joint Program Office for Chemical and Biological Defense. In this situation, the Army must be sufficiently involved and aware so that it can influence the S&T investments of other agencies and benefit from the results of those investments. 3   The term cross-cutting technologies implies the merging of technologies that are being devel

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Science and Technology for Army Homeland Security: Report 1 evance for HLS in I and W as well as in denial and survivability (Chapter 3). High-performance sensors, which image in a broad range of spectral bands, are a high priority for numerous theater and national missile defense platforms. The Department of Defense (DoD) in general and the Army specifically have broad programs in imaging sensors. Applications in addition to infrared (IR) imaging—such as techniques for sensing threats due to harmful chemical and biological agents—may be incorporated in different sensor suites. These system applications would require narrow spectral discrimination over broad spectral bands, low-light-level detection, increased sensitivity, and the ability to perform multifunctional imaging. Detectors with responsivity in the IR atmospheric transmission band are desirable for the detection of terrestrial sources against a 300 K background. The main detectors currently available or in research include the following: HgCdTe imaging IR arrays, Uncooled bolometer arrays, GaAs quantum well arrays, GeSi internal photoemission detectors, GaSb intersubband and Type II detectors, and GaN detectors. In addition to the thermal sensors described above, the Army has relied very heavily on night vision goggles as a primary imaging technology to support night operations. These goggles are used both for target acquisition and navigation, including pilotage. As an image intensification device, night vision goggles rely on the amplification of ambient light, such as starlight or moonlight. The Army is currently working on the fourth-generation image intensification device, with each generation of device becoming progressively smaller and more efficient. The Army has broad programs in most of the above-listed detectors, particularly the first three, and there is ongoing research for improving their performance as well as for studying the causes and modes of degradation and failure. DARPA has several ongoing programs in lasers and nitride detectors for the ultraviolet and solar blind regions. In a situation where chemical or biological agents have been released into the atmosphere, this technology may be significant for standoff chemical and biological detection, as biological agents in particular have very specific signatures of absorption or emission in the ultraviolet portion of the spectrum.4Table 2-1 describes traditional imaging sensors.     oped independently and that are multidisciplinary in nature as well as perhaps being multiuse for a greater payoff. 4   Detecting an aerosol cloud is much easier than characterizing what is in the cloud, but if the nature of the biological cloud is already known from other measurements, it should be possible to track the specific cloud and monitor its dispersion.

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Science and Technology for Army Homeland Security: Report 1 TABLE 2-1 Technologies for Perimeter Defense and Warninga Technology Characteristics Availabilityb (R, N, F) Priority for Army S&Tc Multiused (H, O, C) HgCdTe imaging LWIR arrayse Material of choice to fabricate high-performance detector arrays. Energy gap can be tailored in the range from 1.4 to 20 microns. R High H, O, C Uncooled bolometer arrayse Utilizes temperature-dependent dielectric constants and operates at room temperature. BaSiTiO3 (BST) is ferroelectric below a Curie temperature (Tc) of nearly 300 K. Current devices are optimized for response in the mid- and long-wave IR band, but in principle future bolometers can be made with a wide variety of responses using different absorptive coatings. R-N High H, O, C GaAs quantum well arrayse A quantum well detector can be thought of as a type of extrinsic photoconductor in which the bound electrons reside inside the quantum wells instead of on dopant ions. R-N High H, O, C

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Science and Technology for Army Homeland Security: Report 1 GeSi internal photoemission detectors Makes use of the high internal photoemission of the GeSi alloy. N-F Low H, O, C GaSb intersubband and Type II detectorsf Potential for tunability and design F Low H, O, C GaN UV detectors for solar blind applicationsg UV light selectively ionizes chemical agents. Ion detector determines concentration F Highh H, O, C NOTE: LWIR, long-wave infrared; UV, ultraviolet. aImpacts chemical and biological technologies. bAvailability: R, ready (TRL 8-9); N, near-term (TRL 4-7); F, far-term (TRL 1-3). cPriority for Army S&T (investment): low, someone else has mission or technology is ready and available; medium, useful but of limited impact and some investment needed; high, very important, no one else working on it, considerable investment needed. dMultiuse: H, Army homeland security; O, Objective Force; C, civilian (first responders and others). eWestervelt et al. (1991). fNRL (1998). gDARPA (2002a,b). hDoes not include acoustic, seismic, and radio frequency sensors, which are additional perimeter defense technologies.

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Science and Technology for Army Homeland Security: Report 1 In the process of collecting material for this chapter, data on the performance of many different sensors were examined. As one would expect, the performance or utility of individual sensor technologies was dependent on the environment in which they were used. This led to some confusion in comparing performance among sensors. A consistent methodology would be helpful for reporting the performance of sensors in the environments in which they will actually be used. It makes little sense, for example, to present data on the sensitivity of a particular diagnostic methodology without also presenting the trade-off with specificity.5 The NRC study Making the Nation Safer (NRC, 2002) calls for the following system-design approach: Establishment of standards for response time and field stability/durability, for example, for detection of WMD; Use of two-level sensor systems in which a low false-alarm-rate sensor with low specificity triggers a second sensor with a higher false-alarm rate but higher specificity; Use of multiple sensors and reasoning algorithms to obtain lower overall false-alarm probability, to predict contamination spread, and to provide guidance for recovery actions; and Use of networked sensors to provide wide-area protection of high-threat targets. Conclusion 2-1. In conducting the survey it was often difficult to obtain authoritative and certified data on the real-world performance of many of the indicators and warning sensors in use or in development. This difficulty also applied to data on sensitivity and noise characteristics. Recommendation 2-1. It is critically important that all sensors not only be well characterized at the point of purchase but also be regularly rechecked by competent technicians. Software used to integrate disparate sensors should be well documented and checked against standardized problems. Chemical Agents A number of different technologies are in use or in development for the detection of chemical agents. The agents are typically released by some means 5   One elementary method of accomplishing this is through the use of receiver operating characteristic curves. These curves plot the true positive rate against the false positive rate under conditions appropriate for the test being made. Without such data it is difficult to draw meaningful conclusions from the measurements. The curves generally quantify how an increase in sensitivity is accompanied by a decrease in specificity. They are routinely used in evaluating sensor performance in a broad range of fields, from medical diagnostics to the design of radar systems.

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Science and Technology for Army Homeland Security: Report 1 FIGURE 2-1 Vapor pressure concentrations for a number of chemical agents. SOURCE: Nerve agent data from Augerson (2000); mustard agent data from U.S. Army (undated). into the atmosphere, where they form toxic clouds that are moved by atmospheric winds or by ventilation systems. The most desirable situation would detect these agents before they are released into the atmosphere. For weaponized agents this will be difficult. Figure 2-1 provides the vapor pressure concentrations for a number of chemical agents. When compared with explosives, the chemical agents shown in Figure 2-1 are high-vapor-pressure substances. These concentrations will be easily detected with a number of technologies (however, VX will stress the state of the art for detection in realistic environments). The acceptable exposure levels, however, are much lower than the vapor pressure levels. Figure 2-2 provides the atmospheric exposure limits (AEL) for a variety of chemical agents.

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Science and Technology for Army Homeland Security: Report 1 FIGURE 2-2 Atmospheric exposure limits for a variety of chemical agents. SOURCES: Nerve agent data take from Augerson (2000), CMS (undated); mustard agent data from U.S. Army (undated), CMS (undated). These concentrations are more like those of the most-difficult-to-detect explosives, and one can expect similar problems with sensitivity and false alarms when operating in realistic, dirty environments. In clean environments where interfering substances can be kept to a minimum, the detection of trace amounts of chemical agents is more straightforward. Table 2-2 provides examples of means of chemical agent detection. The use of industrial chemicals to cause harm should receive serious attention. If industrial chemicals are introduced into the atmosphere, they may be easier to detect than chemical warfare agents. At room temperature, chlorine, for example, has a vapor pressure an order of magnitude higher than air, while the vapor pressure of phosgene is about 50 percent higher than that of air; the vapor pressure of hydrogen cyanide is approximately the same as that of air, and the vapor pressure of methyl isocyanate is roughly half the vapor pressure of air. Also, because these chemicals are used routinely for industrial processing there is substantial experience in monitoring their presence at levels established by the Surgeon General as safe. The problem, of course, is that all of the monitoring is done in the industrial environments where these chemicals are expected to be present. Terrorists could employ these chemicals in locations where they would not be expected. This creates a sensor distribution problem.

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Science and Technology for Army Homeland Security: Report 1 FIGURE 2-3 Comparative toxicity (amount needed to incapacitate) of biological agents, toxins, and chemical agents. SOURCE: NIJ (2001). It should be noted that a number of these technologies also have relevance to the detection of conventional explosives and are therefore appropriate candidates for Army S&T investments for that purpose. Ion mobility spectrometry has broad application. The measurement presents a mass spectrum for fragments that are introduced into a drift chamber. Interpretation of this mass spectrum is where specific subject matter expertise comes into play. Interpretation of the spectrum for biological applications requires very different expertise than, say, interpretation of the spectrum collected in an explosives detection test. This technology could certainly be considered as cross-cutting in much the same sense that quantum dots technology is cross-cutting in its applications. Biological Agents The point detection of biological agents is qualitatively different from that of chemical agents. This is seen in Figure 2-3, which compares the amount of biological agent needed to incapacitate an individual with the amounts of chemical agent and toxin needed to incapacitate. Many orders of magnitude less biological agent is required. Most devices for the physical detection of biological agents require that the agent be in the environment. A typical biodetection system involves a queuing, detection, discrimination, and identification sequence. This sequence requires that samples be purified and concentrated so that other species that could potentially interfere with detection of the target agent are reduced to a minimal level. Some of the technologies that are utilized or are under investigation for implementing this sequence are listed in Table 2-3. There are many promising opportunities for investing S&T funding in support of biological agent detectors. Responsibility for this area, however, has been assigned to the Joint Project Office for Chemical Biological Defense. This limits the investment of Army S&T funding in this important area. There are, however, some undertakings also relevant to explosives detection and many other undertakings relevant to the Objective Force that are within the purview of the DASA (R&T) and that can help advance biodetection S&T. Some of these will be mentioned the next section.

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Science and Technology for Army Homeland Security: Report 1 TABLE 2-2 Technologies for Chemical Agent Detection Technology Characteristics Availabilitya (R, N, F) Priority for Army S&Tb Multiusec (H, O, C) Enzymatic paper Detects nerve gas at ~ppb, HC at ~10 ppm, and mustard gas at ~ppb. Inexpensive, prone to false positives. R Low H, O Ion mobility spectroscopy Detects nerve gas at ~6 ppb and mustard gas at ~10 ppb. 1-2 minutes. Erroneous detection from interference, e.g., smoke. R-N Mediumd H, O, C Photo acoustic IR spectroscopy Highly selective. Sensitive to external vibration. R-N Mediumd H, O, C Differential absorption light detection Tracks identified clouds. Sensitive to environmental noise. R-N Low H, O, C

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Science and Technology for Army Homeland Security: Report 1 Passive IR detection Direct measurement of IR emission or absorption from chemical agent cloud. R-N Low H, O, C Photo ionization UV light selectively ionizes chemical agents. Ion detector determines concentration. R-N Mediumd H, O, C Flame photometry Flame color determines concentration of sulfur and phosphorous. Highly sensitive. Prone to false positives. R-N Low H, O, C Gas chromatography Vapor separation through a column improves flame photometry. R-N Mediumd H, O, C Surface acoustic wave Surface absorption of chemical agents changes resonance frequency. Measures many chemical agents simultaneously. R-N Medium H, O, C NOTE: ppb, parts per billion; ppm, parts per million; UV, ultraviolet. aAvailability: R, ready (TRL 8-9); N, near-term (TRL 4-7); F, far-term (TRL 1-3). bPriority for Army S&T (investment): low, someone else has mission or technology is ready and available; medium, useful but of limited impact and some investment needed; high, very important, no one else working on it, considerable investment needed. cMultiuse: H, Army homeland security; O, Objective Force; C, civilian (first responders and others). dImpacts chemical and biological technologies.   SOURCE: Davis and Kelen (2001).

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Science and Technology for Army Homeland Security: Report 1 TABLE 2-5 Technologies for Vapor-Phase Explosive Detectors Technology Characteristics Availabilitya (R, N, F) Priority for Army S&Tb Multiusec (H, O, C) Ion mobility spectrometerd,e Detects at parts per billion level. Must be close to explosive or chemical. Noise limits become a problem at low signal levels. Fundamental problem in selectivity and resolution. Shows promise for increased detection in low concentrations. R-N Medium H, O, C Chemical resistorse,f Detects at parts per billion level. Must be close to explosive or chemical, needs improved SNR. N High H, O, C Fluorescent polymersd Detects at parts per trillion level (in principle). Must be close to explosive or chemical, needs improved SNR. Demonstrated at parts per billion in reliable system. R-N High H, O, C Gas chromatography + SAWd,g Detects at parts per billion level. Must be close to explosive or chemical, must be able to desorb the explosive vapors for system to be useful. R-N Medium H, O, C Surface-enhanced Raman spectroscopyd Detects at parts per billion. Portable, must be close to explosive. N-F High H, O, C Immunoassay (biosensors)d Detects parts per billion. Must be close to explosive. Potential for increased sensitivity. N-F High H, O, C NOTE: SNR, signal-to-noise ratio; SAW, surface acoustic wave. aAvailability: R, ready (TRL 8-9); N, near-term (TRL 4-7); F, far-term (TRL 1-3). bPriority for Army S&T (investment): low, someone else has mission or technology is ready and available; medium, useful but of limited impact and some investment needed; high, very important, no one else working on it, considerable investment needed. cMultiuse: H, Army homeland security; O, Objective Force; C, civilian (first responders and others) dWard et al. (2001). eLewis et al. (1997). fBruschini and Gros (1997). gU.S. Navy (2002).

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Science and Technology for Army Homeland Security: Report 1 factured low-vapor-pressure explosives will assist in both detection and forensic analysis. Recommendation 2-2. An international convention requiring the incorporation of detection markers and identification taggants should be sought. Bulk-phase detection of explosives generally involves some form of interrogation of the explosive. All of the systems require close proximity to the material being interrogated. Table 2-6 describes examples of bulk explosive detection. Conclusion 2-3. The physical detection of dangerous packaged materials (nuclear weapons, radiological weapons, chemical weapons, biological weapons, and explosive weapons) is an extremely difficult and stressing task, even when the materials are forced through choke points. CROSS-CUTTING TECHNOLOGIES It is quite clear that the great majority of technologies for the physical detection of nuclear weapons, radiological weapons, conventional explosives, chemical agents, and biological agents require close proximity to the weapon. Detection of chemical or biological aerosol clouds at a distance is possible. However at that point, the attack is already under way. Similarly, the use of health and medical surveillance, while very desirable, is a post-attack undertaking. The most desirable indication and warning would signal the presence of dangerous material before an attack has begun. While efforts should continue to improve pre-event detection ranges for individual sensors, it is clear that the laws of physics, chemistry, and biology will impose severe limits on these ranges. This would seem to leave two options for the physical detection of dangerous materials: One option is to force all material to move through choke points or portals. This will bring the detectors and the dangerous materials into proximity, thereby easing the burden on detector technology. The second option would involve distributing large numbers of detectors, making it difficult to avoid detection by avoiding choke points and portal systems. This second option would require inexpensive detectors that can be widely proliferated. It would also require sophisticated networking of the detectors and the development of systems to intelligently interpret the data provided by them. The distributed network would involve fixed sensors and mobile sensors deployed on various platforms, including autonomous unmanned air, space, ground, and underwater vehicles. This option opens up substantial opportunities for the investment of Army S&T resources because the S&T involved is appli-

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Science and Technology for Army Homeland Security: Report 1 cable to the Army for more than just nuclear weapons detection or chemical and biological agent detection. For example, the intelligent networking of sensors involves S&T that cuts across many applications of interest to the Objective Force, including perimeter defense, tracking, identification, and targeting. Similarly, the S&T needed to develop inexpensive small sensors for wide proliferation would involve studies that are much broader than those specific to HLS. Indeed, the most significant advances in detection technologies may come from the innovative combination of very disparate technologies into compact integrated sensor suites. The S&T for the required autonomous unmanned sensor platforms is of great interest to the Objective Force and will have an important impact. Learning how to do all of this will be of very broad interest to the Army. In addition to existing or anticipated ideas for detection, the committee thought it worthwhile to highlight more speculative means for detection in Box 2-1. There are many examples where cross-cutting technologies have had an impact well beyond that initially envisioned. Consider the case of fiber-optic sensors. These were originally developed by the DoD to provide for the sensitive detection of acoustic, magnetic, and strain signatures. In one variation, these detectors utilize evanescent field excitation, whereby a portion of the light traveling in the fiber core penetrates the surrounding medium with the power of the evanescent field decaying exponentially from the fiber core. Through a clever combination of surface chemistry, biological or chemical receptors can be bound to the surface of the cladding. By introducing a fluorophore into this arrangement and monitoring the change in fluorescence that occurs when specific binding takes place at the surface of the fiber it was possible to create a fiber-optic detector for certain chemicals and biological entities. This is an example where S&T developed by DoD for purposes having nothing to do with chemical or biological detection has made an important contribution to the detection of biological agents. As another example, consider the S&T that has been supported by DoD in semiconductor quantum-dot nanocrystals. These quantum dots have been shown to have emission spectra that may be tuned by changing the quantum-dot radius. For example, quantum dots may be fabricated so that a 2-nanometer particle glows bright green while a larger 5-nanometer particle glows red in the presence of white light. These developments originally had nothing to do with the detection of chemical or biological agents, but the dual-use potential was found through clever chemistry. The utility of this approach is limited by the efficiency of the immunoassay or the DNA identification technique. It remains to be seen whether or not a viable detection system can be developed for quantum dots. It should be clear from the above discussion that the cross-cutting technologies could have a broad impact and should be of very great interest to the DASA (R&T). Some examples of relevant cross-cutting technologies are shown in Table 2-7.

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Science and Technology for Army Homeland Security: Report 1 TABLE 2-6 Technologies for Bulk Explosive Detection Technology Characteristics Availabilitya (R, N, F) Priority for Army S&Tb Multiusec (H, O, C) Transmission x-rayd,e Portal system provides 2-D images. R Low H, O, C Transmission gamma raye Portal system provides 2-D images. R Low H, O, C Backscatter x-raye Finds low-atomic-number elements (C, H, O, N). Requires close proximity and sophisticated interpretation. R-N Low H, O, C X-ray and gamma-ray tomographye Portal system provides 3-D images. R Low H, O, C Thermal neutron analysis (TNA)d,e,f Portal system: capture of thermal neutron by nitrogen gives 10.8 MeV gamma ray. R-N Low H, O, C Fast neutron analysis (FNA)e Portal system: stimulates gamma radiation from elements being irradiated. R-N Low H, O, C

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Science and Technology for Army Homeland Security: Report 1 Pulsed fast neutron analysis (PFNA)e,f Portal system: stimulates gamma radiation from elements being irradiated. R-N Low H, O, C Nuclear magnetic resonance (NMR)ef All samples must be passed through magnetic coils. Chemical interpretation of NMR transitions can determine composition. R Low H, O, C Nuclear quadrupole magnetic resonance (NQR)e,f Low SNR, must be close to explosive, does not require magnets. Produces RF signals characteristic of particular explosives. R-N High H, O, C Millimeter-wave radiometry f,g Potential to provide radiometric images of objects (e.g., explosives) under clothing. N High H, O, C NOTE: 2-D, two-dimensional; 3-D, three-dimensional; MeV, mega-electron-volt; RF, radio frequency. aAvailability: R, ready (TRL 8-9); N, near-term (TRL 4-7); F, far-term (TRL 1-3). bPriority for Army S&T (investment): low, someone else has mission or technology is ready and available; medium, useful but of limited impact and some investment needed; high, very important, no one else working on it, considerable investment needed. cMultiuse: H, Army homeland security; O, Objective Force; C, civilian (first responders and others). dWard et al. (2001). eU.S. Navy (2002). fBruschini and Gros (1997). gNRC (1996).

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Science and Technology for Army Homeland Security: Report 1 TABLE 2-7 Examples of Cross-Cutting Technologies Application Technology Characteristics Availabilitya (R, N, F) Priority for Army S&Tb Multiusec (H, O, C) Detection and tracking Sensor networking (see Box 2-1) Gathers data from a wide variety of spatially distributed sensors. N-F High H, O, C Sensor fusion Intelligently combines, correlates, and interprets data from distributed sensors. N-F High H, O, C Anomaly detection Examines data from networked sensors to discover patterns, unusual behavior, etc. N-F High H, O, C Surveillance platforms (UAVs, UGVs, UUVs) Small autonomous vehicles for carrying sensor payloads as part of distributed sensor network. R-F High H, O, C Perimeter surveillance IR, RF, acoustic, seismic, etc. techniques Monitors for intrusion into predetermined spaces (encampments, facilities, borders, etc.). R-N High H, O, C

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Science and Technology for Army Homeland Security: Report 1 I and W capability in miniaturized systems MEMS Methods for integration of many technologies into microsensors using electronic fabrication technologies. R-F High H, O, C Active-passive sensor suites Suites of lasers and detectors that can query and image as well as perform spectroscopic measurements. N-F High H, O, C Nanofabrication techniques Fabrication of sensing systems at the atomic level. F High H, O, C NOTE: UAV, unmanned air vehicle; UGV, unmanned ground vehicle; UUV, unmanned underwater vehicle; IR, infrared; RF, radio frequ ency; MEMS, microelectromechanical systems. aAvailability: R, ready (TRL 8-9); N, near-term (TRL 4-7); F, far-term (TRL 1-3). bPriority for Army S&T (investment): low, someone else has mission or technology is ready and available; medium, useful but of limited impact and some investment needed; high, very important, no one else working on it, considerable investment needed. cMultiuse: H, Army homeland security; O, Objective Force; C, civilian (first responders and others).

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Science and Technology for Army Homeland Security: Report 1 BOX 2-1 Speculation on Means of Detection Using the Existing Telecommunications Infrastructure The committee notes in Table 2-4 that glass fibers subjected to gamma radiation near background levels scintillate. Although the scintillation is weak, it is detectable and the effect is used to detect gamma radiation. The telecommunications industry has introduced a good deal of glass fiber into the country’s infrastructure. Those fibers that are above ground undoubtedly exhibit some level of optical noise due to the gamma radiation background. This background radiation level will increase if a gamma radiation source approaches the fiber. If this were detectable, then the telecommunication optical fiber infrastructure might itself serve as a distributed network of gamma-radiation detectors. As another example, consider the fact that the natural background of thermal neutrons has been shown to cause single-event upsets in microelectronics. The thermal neutrons interact with the boron-10 fraction of boron dopants, producing alpha particles. The energy deposited by the alpha particles causes the upsets. Perhaps this effect could be exploited to produce a highly distributed thermal neutron detection system by incorporating a special boron-doped chip in cell phones. When a phone “shakes hands” with a cell tower, it could pass a neutron anomaly message and its GPS coordinates, if equipped to do so. If something like this were feasible it would result in a worldwide distributed network of thermal neutron detectors. SUMMARY A new approach is required for the indication and warning stage for chemical, biological, radiological, nuclear, or high explosive weapons. There are many opportunities for the Army S&T program to help in defining that new approach. The new approach might involve the proliferation of small but competent sensor systems into some sort of intelligent network. Exploitation of the nation’s existing infrastructure should be examined. Such an undertaking would require expanding the community currently working on indications and warning. The collective skills of this community might enable a new class of detector system that makes it difficult to position terrorist weapons so that they are a threat to U.S. forces or to the general population. This distributed sensors approach offers many important opportunities for investigation by the Army S&T program. The Army’s role in funding S&T for detectors of CBRNE weapons is very limited. There are, however, numerous opportunities for synergy among legitimate Army S&T investments and the investments of others in detector technologies. This is especially true of cross-cutting technologies. Many important contributions to I and W sensor capability are likely to come from developments in fields not traditionally associated with CBRNE weapons

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Science and Technology for Army Homeland Security: Report 1 or the detection thereof. The stovepipe communities,9 funding agencies, and funding mechanisms that have been set up in CBRNE weapons areas, while very effective in cases where it is known how to solve a problem, can be counterproductive in this situation. The interrelationships needed among the sensor networks and for the broader intelligence collection activity are difficult to establish, for technical, cultural, and legal reasons. Nevertheless, the committee envisioned a situation where the relevant sensor networks would be queued as a result of intelligence findings, with the intelligence community tasked to undertake focused collection efforts if the sensor networks picked up unusual activity. There are serious scientific and technical questions here even if the cultural and legal issues can be resolved. For example, the ability to quickly and reliably search massive databases for anomalous activity would be critical for the implementation of this recommendation. It may be necessary to create a research organization to resolve this problem, and it is unlikely that any one institution can take this on. A consortium approach might work, but it would be confronted by serious if not insurmountable security classification problems. Conclusion 2-4. A purely technical solution to the indications and warning problem based upon sensors, even networked sensors, is unlikely. Establishing the proper interrelationships among the sensor networks and the broader intelligence collection activity will be crucial for properly queuing the sensor network. Recommendation 2-4a. The Army should ensure from the outset that the necessary interrelationships among the sensor networks and the broader intelligence collection activity are established and maintained as a coherent undertaking. Recommendation 2-4b. Army science and technology should aggressively seek out and invest in those cross-cutting sciences and technologies that will benefit both the Objective Force and the homeland security requirement to detect weapons of mass destruction. 9   A “stovepipe” community is a relatively closed community where certain franchises have been granted. These communities tend to be insular in terms of their involvement with larger communities, but they can be multidisciplinary. It is often very difficult for an outsider to break into these communities. They can be very effective when one knows how to solve a particular problem and it is simply a matter of assembling a team to get it done. They are less effective where solutions are not obvious and where truly new ideas are required. In the case of homeland security new ideas are clearly needed, and the government should be seeking the broadest possible involvement until a solution is at hand.

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