Abstract:
The invention provides a method and apparatus for detecting the presence of explosives in the trunk or rear area of a vehicle using neutron invasion of that vehicle area and resulting gamma ray sensing resulting from the reaction of the neutrons, typically fast neutrons, with explosives therein enhanced by the interaction of the neutrons with fuel, the neutron generation and gamma ray sensing being in equipment located in speed bumps or recessed below the road surface.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Patent Application No. 61/857,641, filed Jul. 23, 2013, the disclosure of which is incorporated by reference herein. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to noninvasive detection of explosives concealed in automobiles. 
       BACKGROUND OF THE INVENTION 
       [0003]    Detection of explosives concealed in vehicles a.k.a. Carbombs, are a top national security priority issue in the War Against Terrorism. Carbombs are a present danger and increasing menace to peace and stability in Europe, Middle East and Asia. Large explosive assemblies of 50 to 1000 lbs are 98% of the time placed in automobile&#39;s trunks and remotely exploded by a suicidal driver while passing in front of the buildings and facilities (Iraq, Afghanistan, Indonesia). In another modus operandi, Carbombs are placed in parked unattended cars and remotely triggered by mobile telephones when the target car or individual is passing by (Spain, Lebanon, Israel, Russia, S. Arabia). Detection of an explosive is a 2 step process: (1) primary or anomaly detection, i.e. the detection of “possible” explosive and (2) secondary or confirmation detection, which conclusively determines by a close examination (until now always manual) whether the anomalous object contains explosive or is a “false alarm.” 
         [0004]    Today, counter measures to Carbombs are a combination of noninvasive and invasive inspection of the stopped cars, emptied of passengers at the entry checkpoints. Noninvasive checkpoint methods are under the car imagers of the chassis, seeking anomalous shapes, coupled to visual inspection of the car through windows. This is followed by invasive manual inspections and dog sniffing of the vehicle and trunk interior. In some installations X ray inspection is performed. All currently used X-ray based explosive detection systems (EDS) are chemically blind. They can image the locations, shapes and density of hidden objects but have no ability to chemically determine whether they are explosives or not and hence require manual inspection. Without X ray inspection, a minimum average inspection time per vehicle is 3 minutes, thus resulting in a throughput of 20 cars/hour. The security agencies&#39; requirement is 10 times greater, i.e. at least 100 vehicles/hour. Prior systems employ Atometry principles as shown in Appendix A. 
       BRIEF SUMMARY OF THE INVENTION 
       [0005]    The method and apparatus of this invention is projected to increase the throughput rate to 440 vehicles/hour. 
         [0006]    Specifically, this patent application is directed to major improvements of the SCI process (1) by concealing the detector system under speed bump, (2) portability of the system with easy assembly and disassembly features at permanent and improvised checkpoints, and (3) greatly reduced vehicle inspection time over that by SCI resulting in (4) a significantly increased vehicle throughput; the latter, (3-4), are achieved by using a radically improved method and technique of Fast Neutron Atometry, published in “Birth of Atometry” by B. Maglich noted above. 
         [0007]    This is accomplished by a combined action of (a) Differential Neutron Elementry as primary detector and (b) Double Neutron Atometry as a confirmation sensor. The latter is a simultaneous 2-beam (thermal &amp; fast neutron) illumination of the object in the trunk by making fast neutron passage through the gasoline tank. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  illustrates the used SIEGMA 3E3 atometer robotically carried to investigate a briefcase for explosives; 
           [0009]      FIG. 2  is a graph comparing gamma ray spectra of fast neutron explosive systems, ANCORE, for pulsed neutrons versus low resolution gamma detectors with measurement by non-pulsed, solid state gamma detector atometer; 
           [0010]      FIG. 3  shows an atometer housed in the briefcase of  FIG. 2  and showing the components of the atometer, disguised in the suitcase, comprising an accelerator (neutron generator), germanium detector, and processing electronics; 
           [0011]      FIG. 4  shows a screen display for the operator to view the results of the atometer in use; 
           [0012]      FIG. 5  pictorially illustrates the use of the atometer device adapted for use in a speed bump according to the invention; 
           [0013]      FIG. 6  diagrammatically illustrates the components of the atometer from the suitcase as employed in a speed bump detector; 
           [0014]      FIG. 7  is a side view illustrating the components of the atometer of the invention in a speed bump; 
           [0015]      FIG. 8  diagrammatically illustrates the components of the atometer from the suitcase as employed in a speed bump according to the invention; 
           [0016]      FIG. 9A  illustrates a vehicle approaching a pair of speed bumps, including the atometer according to the invention; 
           [0017]      FIG. 9B  illustrates the vehicle beginning to pass over the speed bumps; 
           [0018]      FIG. 10  pictorially illustrates a portable rolling speed bump according to the invention allowing it to be positioned under a vehicle trunk to detect explosives within the vehicle trunk; 
           [0019]      FIG. 11  is a diagrammatic view showing radiation paths for detecting explosives in the trunk of the vehicle between two speed bumps. 
           [0020]      FIG. 12  illustrates a portable device for displaying the results of the explosive exploration. 
           [0021]      FIG. 13  illustrates an embodiment of the invention wherein the explosive detection equipment is installed below a road surface; 
           [0022]      FIG. 14  illustrates the use of the embodiment of  FIG. 13  for a vehicle passing there above; 
           [0023]      FIG. 15  illustrates in cross-section the detection device of the invention installed below a roadway surface. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0024]    Since 98% of car bombs are concealed in trunks, the invention is described for an embodiment of Carbomb detection in terms of detection of a bomb, typically of 100 lbs or more, in the trunk of an automobile. It is sketched in  FIGS. 5-11 . 
         [0025]    Atometry is stoichiometry by means of neutrons. It is a non-intrusive diagnostic process that provides stoichiometry of unknown substances by irradiating them with fast neutrons of femtometer (10 −15  m) wave-length. The technique deciphers, in real time empirical chemical formulas of unknown objects, C a N b O c , where a, b, and c are the atomic proportions of carbon, nitrogen, and oxygen, with a 97.5% (2σ) statistical probability. 
         [0026]    Military explosives consist of 4 elements: H, C, N and O. E.g. stoichiometry of TNT is C 7 N 3 O 6 H 5 . For RDX, used in plastic bombs, it is C 6 N 6 O 6 H 6 . Non-military explosives, e.g. homemade terrorist bombs, are also detectable by atometry although they contain other elements, notably chlorine. The presence of nitrogen, often incorrectly referred to as to ‘explosive signature’ is only a “possible explosive indicator”. 1 m3 of air contains nearly a kilogram of N 2 . Qualitatively detecting the mere presence of one or more elements of the explosive does not make an explosive detector. 
         [0027]    Since first neutron count excites H, the task of atometry is to obtain, in a shortest time possible, quantitative atomic ratio of the 3 elements i.e. the subscripts a, b, c in C a N b O c , to an accuracy sufficient to discriminate explosives from 1,000-odd innocuous substances also containing C, N and O. The atometry algorithm calculates the relative number of atoms of C, N and O and plots them onto a 3-dimensional view in which each C:N:O ratio is representing by a dot. 
         [0028]    Atometry is achieved by quantitative measurement of high-resolution γ spectra emitted from inelastic scattering of fast neutrons. Neutrons of E=5-50 MeV, have a DeBroglie wave-length of the order of femtometer and so collide directly with the nuclei of C, N and O, unaffected by their chemical bonds or aggregate state. They produce characteristic γ&#39;s from each of the 3 elements, γ energies being 4.4, 5.1 and 6.1 MeV, respectively. 
         [0029]    Neutrons are produced by a DC (non-pulsed) beam of deuterons in the reaction: d+t→α+n+17.8 MeV (1). Next, they interact with nuclei of elements X: n+X→X*→X+γ+n′ (2), where γ&#39;s are emitted by the transition between energy levels of X, the energy spectra of which are element-specific. 
         [0030]    The irradiation time is decided upon by the algorithm in each case until the statistical error on the atomic proportions (a, b, c) reaches 2σ, which corresponds to 95% confidence level. Depending on target mass, this takes anywhere from 5 sec. to 5 min. If 95% confidence is not reached in 5 minutes, the result is inconclusive, and re-measurement of new conditions (distance, intensity, etc.) is attempted by the operator. 
         [0031]    The present invention adapts known technology to the use in a speed bump for automobiles to pass over, while the technology is applied to generate neutron exploration of trunk contents while the vehicle moves over the bump. 
         [0032]      FIG. 1  illustrates a suitcase  12  containing exploratory and sensing electronics as described below and safely carried without human intervention on a mobile robot  14  to sense the contents of a briefcase  16 . The briefcase  12  in this environment uses a SIEGMA 3E3 sensing apparatus as described below to pass neutrons into the briefcase  16  and sense gamma rays from which the presence of explosives can be determined using known technology. 
         [0033]    The present invention uses a known ATOMETER gamma ray detector system as opposed to other systems such as the ANCORE system. The latter uses pulsed neutron while the former is non-pulsed. The latter system response is illustrated in the slightly curved line of  FIG. 2 , while the ATOMETER output is illustrated in the sharply hashed line. The detection of the relevant chemicals for explosives is illustrated by sharp spikes in the relative explosive chemicals illustrating graphically the high sensitivity for explosive detection in the technology used in the present invention. 
         [0034]    The known technology described above is illustrated in the contents of the suitcase  12  as open in the view of  FIG. 3 . Neutrons are emitted from a source  20  caused by particles accelerated from a particle accelerator  22 . The response of explosives is sensed by a Germainium GammaRay detector  24 , which is made operationally cold by a cryo-cooler  26 . To cause the elements described above to the right in the suitcase view of  FIG. 3  to operate, known electronics  28  are provided in the left portion of the suitcase of  FIG. 3 . The electronics  28  provide by cable or wireless means an output to a known display terminal  30  illustrated in the 4 which may be stationary or in a tablet or cell phone device  80  ( FIG. 12 ). 
         [0035]      FIG. 4  illustrates the display panel as known in the art for use with the ATOMETER Suitcase described above. The system is activated by a button  32  which may enable sensing of any detected gamma rays at the time of activation for the contents of the suitcase continuously in operation or may at that same time start the activation and operation of the suitcase contents. In either case, sensing continues for a period of time, typically 30 seconds as displayed on a panel  34 . The known sensing electronics provides in a display  36  an estimate of the amount of essential chemicals sensed from Gamma ray radiation, particularly carbon, nitrogen and oxygen and in labeled windows  37 . A further display  38  may provide a list and percentage of concentration of all chemicals sensed. The known sensing electronics of  FIG. 4  may also provide an estimate of the weight of the explosives in display  42 , along with a go/no-go or yes/no estimate of the presence of explosives in display  44 . 
         [0036]    A preferred embodiment of the speed bump Carbomb detector of this invention, known as Advanced Explosive Identifier and Recognizer, AXIOR-700 series, is shown in  FIGS. 5 and 6 . Commercially produced standard speed bump ( 48 ) made of composite material, consisting of 4 segments ( 48   a, b, c  and  d ), holds commercially produced neutron generator ( 50 ) manufactured by Thermo Fischer Scientific, Model MP 320, emitting neutrons with a fluence of 5×10 7  and 2 germanium gamma detectors ( 52 ), high resolution HPGD (High Purity Germanium Detector) Model GMX50P4-83 n-type, manufactured by ORTEC, with a gamma energy resolution of 0.2%. A shield  54  separates the emitter and sensor to prevent error signals. 
         [0037]      FIGS. 7 and 8  show elevation and top views of the speed bump having the system of the invention, respectively. 
         [0038]      FIG. 7  illustrates in elevation and sectional view the speed bump of the invention having an approach ramp  53  and an exit at ramp  55 . The power supply  56 , corresponding to electronics  28  previously presented, is typically under the approach ramp  53 . The neutron generator  50 , corresponding to generator  26  previously described, is located directly after the approach ramp  53  separated from the detectors  52  corresponding to detectors  24  previously discussed by the shield  54 . The speed bump  48  sits on a road surface  57 . 
         [0039]      FIG. 8  illustrates diagrammatically the elements of the electronics and generators and detectors of the invention used in the speed bump of  FIG. 7 . The electronics  56  control the cryostat&#39;s  26 , activates the neutron generator  50  ( 20 ) and receives signals from the detectors  52  ( 24 ). The electronics  50  supplies signals to the operator console  58  illustrated in  FIG. 4 . 
         [0040]    Typically, test runs of as many as 100 will be made with vehicles both having and not having explosive content of various weights in order for the electronics  56  to be calibrated so that the detection of the three main chemicals, H, C and O can be related to the presence or absence of an explosive and an estimate of the size of the explosive device. 
         [0041]      FIGS. 9A, 9B and 11  illustrate the bomb inspection procedure in 3 sequences. Starting in  FIG. 9A , as the car approaches a set of two speed bumps  60  and  62 , the front wheels traverse both bumps  60  and  62  in  FIG. 9B . When the car stops in the valley between the two speed bump structures in  FIG. 11 , the rear one being active and front a dummy, measurements are made. 
         [0042]    In an alternative embodiment of  FIG. 10  designed to check the standing or parked vehicles, be it attended or unattended, an active (rear) section  66  of the speed bump is used alone, without the dummy one, and it is installed on wheels  68  so that it can slide under the car trunk. 
         [0043]    The trunk and car body inspection procedure below is the same for both embodiments. 
         [0044]      FIG. 11  shows the bomb detection procedure. Fast neutrons  70  emitted from the generator  50  enter an investigated object  72  in the trunk  74  and produce gamma rays  76  which are detected in High Purity Germanium Detector, HPGD,  52 . Some fast neutrons  70  pass through spare tire  78  and enter fuel tank  80 , where the are converted into thermal neutrons  82 . The thermal neutrons get captured in the nitrogen nucleus of the investigated object  72  and emit gamma rays  76 ′ which are also detected by HPGD  52 . 
         [0045]    To reduce the throughput time, the invention introduces a two-step Carbomb inspection process, as follows. 
         [0046]    Step 1: Differential elementry. As soon as the vehicle is stopped in the position, in  FIG. 11 , neutron generator  50  illuminates the entire rear end of the vehicle with fast neutrons. Electronics  56  and  58  look for one chemical element difference in the gamma ray spectrum between the average normal car chemical content and that being examined. This invention takes advantage of the property of the explosives that they have more nitrogen (N), than common substances. Hence, detection of greater than normal N content is a pre-signature of an explosive. In this invention the processing in electronics  56  and  58  look first for anomalously high N count above the background N count, averaged over 100 other samples of explosion free vehicles, but not statistically significant more than by 1σ. This is referred to as “differential elementry” and the anomalous N count is pre-alarm which causes the vehicle to stop or be stopped by an attendant. The Differential Elementry process lasts 7 sec. 
         [0047]    Step 2: Dual fast -and- thermal neutron atometry. Only if a pre-alarm occurs in the processing above, the algorithm continues a complete 3-element atometry process to further decipher the gamma rays according to the technology above to determine if it is explosive. Using only the fast neutrons, this process takes 16 seconds. To further shorten the analysis time, this invention increases by 33% the number of “useful” neutrons. This is done by the passage of fast neutrons through the fuel tank at the trunk which results in thermalization of approximately 33% of the neutrons. Thermal neutrons are captured by nitrogen (N) in any explosive present which, in turn, emits gamma rays of 10.8 MeV. Net result is that about 30% more neutrons produce nitrogen based gamma rays which, in return, reduce atometry time to 11 sec. from 16 sec. 
         [0048]    Combining Step 1 and Step 2, there will be times needing only exposure of 7 seconds and those needing exposures of 18 (7+11) seconds. The latter are those with pre-alarm. Assuming a worst case scenario that 1 of 10 cars trips pre-alarm and has to be subjected to full atometry check, the invention obtains 8.2 seconds per vehicle on average, which corresponds to a thruput of 440 cars per hour. 
         [0049]    In a further embodiment of the invention illustrated in  FIG. 13 , the detection device of the invention  90  is installed in a box  92  below a surface  94  bounded by curbs  96 , through which a vehicle will pass for trunk inspection for the presence of an explosive. A typically metal guide  98  protrudes slightly above the road surface  94  to ensure vehicles passing over the detection system  90  will have the trunk properly positioned. 
         [0050]    The box  92  and contents are positioned entirely below the road surface and have above them an aluminum plate  100  with or without apertures to permit neutron and Gamma ray passage. The box  92  contains a neutron generator  102  within container  104 . Surrounding the neutron generator  102  are six gamma ray detectors  106  arranged hexagonally around the generator  102  and at a minimum distance, typically about 15 inches, for interference avoidance. Shielding means  108  may be provided as desired. 
         [0051]      FIG. 14  illustrates the subsurface detection device of the invention  90  in box  92  with neutron emitter  102  and gamma ray detectors  106  below the road surface  94 . In order to position the vehicle  120  for appropriate trunk inspection by the device  90 , a speed bump  110  may be provided to stop the rear wheels  122  appropriately. Alternatively, a barrier  116  may be provided operated by a controller  118  to cause the barrier  116  to raise or lower to a position stopping the vehicle from proceeding for the period of time needed for trunk inspection by the device  90 . 
         [0052]      FIG. 15  illustrates in greater detail sectional and elevational view of the device  90  of the invention showing the contents of the detection device within box  92 . Fans  124  are typically provided for cooling the contents of the box  92  in operation. Where the aluminum cover  100  is perforated, air can easily circulate for cooling purposes. The box  92  has a lower portion with a drainage opening  130  centered therein at a low point into a region  132  of gravel within a ditch  134  for supporting the detection system. 
       APPENDIX A 
       [0053]    Atometry is a bomb inspection process as described in the following articles:
   B. Maglich et al. (1999). Proc. ONDCP International Technology Symposium, p. 9-37. “Demo of Chemically-Specific Non-Intrusive Detection of Cocaine Simulant by Fast Neutron Atometry.” Session A3b-Nonintrusive Inspection Test and Evaluation. (Office of National Drug Policy) Counterdrug Technology Assessment Center, Gov. Doc. NCJ-176972 [www.whitehousedrugpolicy.gov]. http://www.calseco.com/_docs/_released-docs/Demo_detection_of_cocaine_stimulant_by_fast_neutron.pdf;   B. C. Maglich, T.-F. Chuang, M. Y. Lee, C. W. Kamin and C. Druey. (2003). “SuperSenzor′ for Non-invasive Humanitarian Demining.” Session 8—Bulk Explosives Detection, Paper 262. http://www.eudem.vub.ac.be/eudem2-scot/   B. C. Maglich, T.-F. Chuang, M. Y. Lee, C. Druey and G. Kamim. (2003). “MiniSenzor′ for Humanitarian Noninvasive Chemical Identification of UXO Fillers.”, Session 8—Bulk Explosive Detection, Paper 255 (website for both 2 and 3): http://www.eudem.vub.ac.be/eudem2-scot/   B. C. Maglich. (2005). “Birth of ‘Atometry’—Particle Physics Applied To Saving Human Lives”,  American Institute of Physics Conf. Proc .—Oct. 26, 2005—Volume 796, pp. 431-438; LOW ENERGY ANTIPROTON PHYSICS: Eighth International Conference on Low Energy Antiproton Physics (LEAP &#39;05): DOI:10.1063/1.2130207 http://www.fz-juelich.de/leap05/en/ http://link.aip.org/link/?APCPCS/796/431/1