Abstract:
A hazardous materials detection and identification system includes a set of distributed sensors across one or more sides of a self propelled frame structure such as a straddle carrier or similar cargo equipment device. The system non-invasively analyzes vehicles, one or more containers in a stack, a container during lift and movement, a package, cargo, or other objects, that are located in an analysis position relative to the self propelled frame structure for detection and identification of hazardous materials such as chemicals, biological materials, radiological materials, fissile materials, and explosives (CBRNE). The system includes one or more detector arrays that can be configured for various applications such as: shipping container inspection, seaport security, cargo terminal security, airport vehicle inspection, airport cargo inspection, airport baggage inspection, vehicle inspection, truck stop cargo inspection, border protection inspecting vehicles, cargo, persons, railway inspections, railcar inspection, and subway security.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is based on, and claims priority from, co-pending U.S. Provisional Patent Application No. 61/134,405, filed on Jul. 10, 2008, by inventor David L. FRANK, and entitled “High Performance Straddle Carrier CBRNE Radiation Verification System”; and also claims priority from co-pending U.S. Provisional Patent Application No. 61/183,185, filed on Jun. 1, 2009, by inventor David L. FRANK, and entitled “High Performance Straddle Carrier CBRNE Verification System”; and further is based on and claims priority to co-pending U.S. patent application Ser. No. 12/409,758, entitled “Horizontal Sensor Arrays For Non-Invasive Identification Of Hazardous Materials”, filed on Mar. 24, 2009, which is based on and claims priority to prior co-pending provisional U.S. Patent Application No. 61/070,560, entitled “Horizontal Sensor Arrays For Non-Invasive Analysis Of CBRNE Materials Present”, filed on Mar. 24, 2008, by the same inventor; and this application further is based on and claims priority to co-pending U.S. patent application Ser. No. 12/468,382, entitled “Mobile Frame Structure With Passive/Active Sensor Arrays For Non-Invasive Identification Of Hazardous Materials”, filed on May 19, 2009, which is based on and claims priority to prior co-pending provisional U.S. Patent Application No. 61/128,115, entitled “Mobile Frame Structure With Passive/Active Sensor Arrays For Non-Invasive Analysis For CBRNE Materials Present”, filed on May 19, 2008, by the same inventor; and this application further is based on and claims priority to co-pending U.S. patent application Ser. No. 12/468,334, entitled “Radiation Directional Finder And Isotope Identification System”, filed on May 19, 2009, which is based on and claims priority to prior co-pending provisional U.S. Patent Application No. 61/128,114, entitled “Radiation Directional Finder and Isotope Identification System”, filed on May 19, 2008, by the same inventor; and this application further is a continuation-in-part of and claims priority from, co-pending U.S. patent application Ser. No. 11/564,193 entitled “Multi-Stage System for Verification of Container Contents”, filed on Nov. 28, 2006, which is a continuation-in-part of, and claims priority from, prior co-pending U.S. patent application Ser. No. 11/291,574, filed on Dec. 1, 2005, which is a continuation-in-part of, and claims priority from, prior co-pending U.S. patent application Ser. No. 10/280,255, filed on Oct. 25, 2002, now U.S. Pat. No. 7,005,982 issued on Feb. 28, 2006, and that was based on prior U.S. Provisional Patent Application No. 60/347,997, filed on Oct. 26, 2001, now expired; the collective entire disclosure of which being herein incorporated by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention generally relates to mobile frame structures with sensors for detection and identification of hazardous materials, and more particularly relates to a straddle carrier or other self-propelled frame structure with sensors for non-invasive detection of hazardous materials such as chemicals, biological materials, radiological materials, fissile materials, and explosives (CBRNE) in containers. 
       BACKGROUND OF THE INVENTION 
       [0003]    Current designs for radiation detection systems deployed on mobile frame structures such as straddle carriers simply install collimated gamma and neutron detectors in a column on both sides of the straddle carrier. This design is extremely costly and inefficient with heavy materials used for collimation and large straddle carrier frames required to support the weight. The costs of such systems are prohibitive for volume procurement and deployment. The recent concerns over the smuggling of radiological materials to enable a dirty bomb or even an atomic bomb for use by terrorists creates a strong need for a cost effective solution for radiation detection systems deployed on mobile frame structures such as straddle carriers to enable more effective defense systems at borders, stations, and ports. 
         [0004]    Therefore, a need exists to overcome the problems with the prior art as discussed above. 
       SUMMARY OF THE INVENTION 
       [0005]    A high performance design for a straddle carrier, according to one embodiment of the present invention, provides detection and identification of radiation sources such as radioactive materials, gamma radiation emitting materials, and fissile materials. This embodiment of the present invention enables an efficient sensor configuration for a high sensor performance capability with moderate costs. The straddle carrier radiation verification system (SCRVS) provides highly accurate and sensitive non-invasive scanning of containers that are stacked 1, 2, 3 or 4 containers high in multiple columns and/or the scanning of a container during movement. 
         [0006]    For container scanning, the SCRVS deploys radiation sensors deployed on both sides of a straddle carrier to form a target zone. Sensor-detector mounting panels are installed to form a wall on each side of the straddle carrier, from the bottom of the straddle carrier to the top of the straddle carrier. The panels are designed to be one container high. Currently shipping containers are approximately nine feet high. According to one embodiment, gamma sensors are deployed on the inside of these panels and neutron detectors are deployed on the outside of the panels. However, other arrangements of any combination of gamma sensors, neutron sensors, or both, may be deployed on the straddle carrier according to various applications. 
         [0007]    Sodium Iodide (NaI) or similar gamma detectors, according to one embodiment, are deployed on the straddle carrier for scanning container stacks. Up to about 20 2×4×16 NaI sensors are configured on the inside of each panel. These sensors are used to enable scanning of the detectors in the stack with the straddle carrier moving at speeds of up to about three kilometers per hour. 
         [0008]    The NaI detectors are deployed in pairs to provide directional indication of the radiation source materials detected. Such a radiation directional finder system is described in U.S. patent application Ser. No. 12/468,334, entitled “Radiation Directional Finder And Isotope Identification System”, the entire teachings of which being incorporated herein by reference. Such radiation directional finders enable the SCRVS to determine which container in the stack contains the detected radiological material(s). Gamma detector data is provided to a spectral analysis system that utilizes a detection process to detect the presence of radiological materials and to determine the container that holds such materials. The spectral analysis system, according to one embodiment, utilizes software algorithms to analyze radiation data collected from sensors to determine if a specific isotope can be identified. 
         [0009]    Plastic scintillation detectors, for example, are used for neutron detection, such as described in U.S. patent application Ser. No. 12/483,066, entitled “High Performance Neutron Detector with Near Zero Gamma Cross Talk”, the entire teachings of which being incorporated herein by reference. The neutron detectors are deployed, in this example, on the back side of each panel. The neutron detectors utilize collimators to assist in the directional indication of fissile source material(s). The neutron detector data is provided to the spectral analysis system to detect the presence of fissile materials and to determine the container that holds such materials. 
         [0010]    A gross count of gamma detection across the container is used to map the container being scanned and to illustrate the gross gamma detection collected across the container. 
         [0011]    The SCRVS identifies the specific container(s) where the radiological or fissile materials are detected. The container(s) is/are then noted for secondary scanning. 
         [0012]    The secondary scanning device, according to one embodiment, comprises a group of one or more high resolution sensor devices such as germanium detectors. The germanium detectors are provided with cryocooler support to reduce the operational temperature to a desired level. The high resolution sensors are mounted on an elevator. The elevator raises or lowers the high resolution sensors to the desired container position for secondary analysis. The SCRVS then moves to scan the targeted container at speeds of up to about 1.5 kph and provides detector data to the spectral analysis system for isotope identification. 
         [0013]    The use of an elevator system for the high resolution sensors reduces the need to deploy a large number of these costly sensors where they are needed. In other words, the use of the elevator system allows a concentrated number of high resolution sensors to be moved into position to perform a high speed and highly accurate analysis of an individual targeted container position in a stack of containers in a very cost effective manner. 
         [0014]    To perform container inspection during container movement, according to one embodiment, the straddle carrier includes a spreader bar that is equipped with gamma and neutron sensors across the top of the container. In addition to the spreader bar mounted sensors, horizontal sensor rails can be mounted on the sides of the straddle carrier, shuttle carrier, or cargo movement device, that extend out to place gamma and or neutron detectors along the bottom portion of the container. This sensor arrangement provides a multi-sided array of sensors to scan the container to enable greater sensitivity. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    The accompanying figures where like reference numerals refer to identical or functionally similar elements throughout the separate views, and which together with the detailed description below are incorporated in and form part of the specification, serve to further illustrate various embodiments and to explain various principles and advantages all in accordance with the present invention. 
           [0016]      FIG. 1  is a block diagram illustrating a top view of an example of a self propelled frame structure with various sensors scanning one or more containers in a stack, according to one embodiment of the present invention. 
           [0017]      FIG. 2  is a block diagram illustrating a second example of a self propelled frame structure with various sensors scanning one or more containers in a stack, according to one embodiment of the present invention. 
           [0018]      FIG. 3  is a block diagram illustrating an example of a hazardous materials detection and identification system, according to one embodiment of the present invention. 
           [0019]      FIG. 4  a perspective view of an example of a straddle carrier comprising one or more sensor arrays for detection and identification of hazardous materials, according to one embodiment of the present invention. 
           [0020]      FIGS. 5 and 6  are schematic diagrams illustrating side views of the straddle carrier shown in  FIG. 4 . 
           [0021]      FIGS. 7 and 8  are side views of a gamma scanning sensor array panel, according to one embodiment of the present invention. 
           [0022]      FIG. 9  is a side view of multiple gamma scanning sensor array panels, according to one embodiment of the present invention. 
           [0023]      FIGS. 10 and 11  are side views of a neutron scanning sensor array panel, according to one embodiment of the present invention. 
           [0024]      FIG. 12  is a side view of multiple neutron scanning sensor array panels, according to one embodiment of the present invention. 
           [0025]      FIG. 13  is a side view of a gamma sensor array elevator arrangement, according to one embodiment of the present invention. 
           [0026]      FIG. 14  is a side view of a gamma sensor array with a sensor interface unit, according to one embodiment of the present invention. 
           [0027]      FIG. 15  is a block diagram illustrating an example of a source location process, according to one embodiment of the present invention. 
           [0028]      FIG. 16  is a side view of an example of a directional detector set, according to one embodiment of the present invention. 
           [0029]      FIG. 17  is a graph showing test results for directional indication using a directional detector set, according to one embodiment of the present invention. 
           [0030]      FIG. 18  is a side view of an example of a horizontal sensor rail and further showing the sensor rail in an extended position and in a retracted position, according to one embodiment of the present invention. 
           [0031]      FIG. 19  is a side perspective view of an example of a straddle carrier with sensor arrays on a spreader bar and on one or more horizontal sensor rails, according to one embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0032]    As required, detailed embodiments of the present invention are disclosed herein. However, it is to be understood that the disclosed embodiments are merely examples of the invention, which can be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one of ordinary skill in the art to variously employ the present invention in virtually any appropriately detailed structure and function. Further, the terms and phrases used herein are not intended to be limiting; but rather, to provide an understandable description of the invention. 
         [0033]    The terms “a” or “an”, as used herein, are defined as one or more than one. The term plurality, as used herein, is defined as two or more than two. The term another, as used herein, is defined as at least a second or more. The terms including and/or having, as used herein, are defined as comprising (i.e., open language). The term coupled, as used herein, is defined as connected, although not necessarily directly, and not necessarily mechanically. 
         [0034]    The terms “program”, “computer program”, “software application”, and the like as used herein, are defined as a sequence of instructions designed for execution on a computer system. A program, computer program, or software application may include a subroutine, a function, a procedure, an object method, an object implementation, an executable application, an applet, a servlet, a source code, an object code, a shared library/dynamic load library and/or other sequence of instructions designed for execution on a computer system. 
         [0035]    A data storage means, as defined herein, includes many different types of computer readable media that allow a computer to read data therefrom and that maintain the data stored for the computer to be able to read the data again. Such data storage means can include, for example, non-volatile memory, such as ROM, Flash memory, battery backed-up RAM, Disk drive memory, CD-ROM, DVD, and other permanent storage media. However, even volatile storage such as RAM, buffers, cache memory, and network circuits are contemplated to serve as such data storage means according to different embodiments of the present invention. 
         [0036]    Various embodiments of the present invention overcome problems with the prior art by providing a distributed array of sensors including one or more horizontal arrays allowing a brief stop of a vehicle or container for analysis. The various embodiments provide for (1) an ability to scan the contents of a vehicle/container as it enters and exits a detection zone, (2) a fixed geometry between each sensor array in the distributed array of sensors and the target materials when the vehicle/container is stopped, (3) an ability to analyze the vehicle or container within seconds from a single position, and (4) adequate spectral data acquisition within seconds enabling identification of CBRNE materials. 
         [0037]    One embodiment of the invention includes gamma and neutron sensors that can be deployed in a distributed sensor network around a target area (or detection zone) and configured as an array for vehicle/container analysis. The gamma and neutron sensors are deployed on both sides of the detection area and in multiple positions on each side to provide adequate coverage of the full vehicle/container lengths. The sensors can be configured as one or more horizontal arrays positioned, for example, along a centerline of a container to be inspected to minimize the number of sensors required and to optimize data acquisition times. 
         [0038]    The sensors are connected via one or more Sensor Integration Units (SIU&#39;s) that provide the calibration, automated gain control, calibration verification, remote diagnostics, and connectivity to the processor for spectral analysis of the sensor data. One example of such an SIU is described in U.S. Pat. No. 7,269,527 entitled “System Integration Module for CBRNE Sensors”, which is herein incorporated by reference. 
         [0039]    The sensors may also be shielded from electro-magnetic-interference (EMI). A data collection system, electrically coupled with each sensor device, collects signals from the sensor devices. The collected signals represent whether each sensor device has detected gamma or neutron radiation. Optionally, a remote monitoring system is communicatively coupled with the data collection system to remotely monitor the collected signals from the sensor devices and thereby remotely determine whether one or more gamma/neutron sensor devices from the array have provided gamma radiation data or neutron radiation data, and a spectral analysis system identifies the specific isotopes detected by the sensors, as will be more fully discussed below. A user interface provides sensor related data, such as a graphic presentation of the data from each sensor and group of sensors, the detection of radiation, and the identification of the one or more isotopes detected by the sensors. 
         [0040]    Described now is an example of a Straddle Carrier Radiation Verification System (SCRVS) for radiation detection and isotope identification and the operation of the same, according to various embodiments of the present invention. 
         [0041]      FIG. 1  shows an example of a sensor deployment for scanning analysis of vehicles and cargo containers using a self propelled frame structure that moves across a container or vehicle under inspection. This arrangement provides significantly improved efficiency and deployment capabilities over conventional detector systems. Gamma radiation sensors and neutron radiation sensors are deployed on the frame structure as shown. One or more high resolution sensor devices such as germanium detectors are mounted on an elevator to move the high resolution sensors into a detection position to perform a high speed and highly accurate analysis of an individual targeted container position in a stack of containers in a very cost effective manner. 
         [0042]      FIG. 2  illustrates one example of a sensor deployment for verification of cargo contents where a self propelled frame structure such as a straddle carrier or shuttle carrier or forklift lifts and carries one or more containers. The one or more containers are lifted using a spreader bar component of the straddle carrier and that includes gamma and/or neutron sensors strategically positioned on top of the container while being lifted by the spreader bar. Additionally, one or more sensor rails, as shown mounted on the sides of the straddle carrier, include gamma and/or neutron sensors positioned about the lower end of the container. This sensor arrangement provides a multi-sided array of sensors to scan the container to enable greater sensor sensitivity. 
         [0043]    With reference to  FIG. 3 , a data collection system  210 , in this example, is communicatively coupled via cabling, wireless communication link, and/or other communication link  216  with each of the gamma radiation sensor devices  202 ,  292  and neutron sensor devices  201  via one or more sensor interface units  224 . The high resolution sensors are moved up and down the frame for optimum positions by the elevator and elevator control  282 . Optionally, a micro-neutron pulse can be added any of the one or more gamma and or neutron detectors  201 ,  202 ,  292 , to enable the identification of materials, and/or to enable the identification of shielded fissile materials within a detection area. The data collection system  210  includes an information processing system that communicates via data communication interfaces with the sensor interface units  224  that collect signals from the radiation sensor units  201 ,  202 ,  292 . The collected signals, in this example, represent detailed spectral data from each sensor device that has detected radiation. 
         [0044]    The data collection system  210  is modular in design and can be used specifically for radiation detection and identification, or for data collection for various types of hazardous materials sensors such as for explosives and special materials detection and identification. 
         [0045]    The data collection system  210  is communicatively coupled with a local controller and monitor system  212 . The local system  212  comprises an information processing system that includes a computer, memory, storage, and a user interface  214  such as a display on a monitor and a keyboard, or other user input/output device. In this example, the local system  212  also includes a multi-channel analyzer  230  and a spectral analyzer  240 . 
         [0046]    The multi-channel analyzer (MCA)  230  comprises a device composed of many single channel analyzers (SCA). The single channel analyzer interrogates analog signals received from the individual radiation sensors-detectors  201 ,  202 ,  292 , and determines whether the specific energy range of the received signal is equal to the range identified by the single channel. If the energy received is within the SCA the SCA counter is updated. Over time, the SCA counts are accumulated. At a specific time interval, the multi-channel analyzer  230  includes a number of SCA counts, which result in the creation of a histogram. The histogram represents a spectral image of the radiation that is present at the radiation sensors  201 ,  202 ,  292 . The MCA  230 , according to one example, uses analog to digital converters combined with computer memory that is equivalent to thousands of SCAs and counters and is dramatically more powerful and cheaper. 
         [0047]    The histogram is used by the spectral analysis system  240  to identify isotopes that are present in materials contained in the container under examination. One of the functions performed by the information processing system  212  is spectral analysis, performed by the spectral analyzer  240 , to identify the one or more isotopes, explosives or special materials contained in a container under examination. With respect to radiation detection, the spectral analyzer  240  compares one or more spectral images of the radiation present to known isotopes that are represented by one or more spectral images  250  stored in the isotope database  222 . By capturing multiple variations of spectral data for each isotope there are numerous images that can be compared to one or more spectral images of the radiation present. The isotope database  222  holds the one or more spectral images  250  of each isotope to be identified. These multiple spectral images represent various levels of acquisition of spectral radiation data so isotopes can be compared and identified using various amounts of spectral data available from the one or more sensors. Whether there are small amounts (or large amounts) of data acquired from the sensor, the spectral analysis system  240  compares the acquired radiation data from the sensor to one or more spectral images  250  for each isotope to be identified. This significantly enhances the reliability and efficiency of matching acquired spectral image data from the sensor to spectral image data of each possible isotope to be identified. Once the one or more possible isotopes are determined present in the radiation detected by the sensor(s), the information processing system  212  can compare the isotope mix against possible materials, goods, and/or products, that may be present in the container under examination. Additionally, a manifest database  215  includes a detailed description of the contents of each container that is to be examined. The manifest  215  can be referred to by the information processing system  212  to determine whether the possible materials, goods, and/or products, contained in the container match the expected authorized materials, goods, and/or products, described in the manifest for the particular container under examination. This matching process, according to an embodiment of the present invention, is significantly more efficient and reliable than any container contents monitoring process in the past. 
         [0048]    The spectral analysis system  240 , according to an embodiment, includes an information processing system and software that analyzes the data collected and identifies the isotopes that are present. The spectral analysis software, in this example, consists of more that one method to provide multi-confirmation of the isotopes identified. Should more than one isotope be present, the system identifies the ratio of each isotope present. Examples of methods that can be used for spectral analysis such as in the spectral analysis software according to an embodiment of a container contents verification system, include: 1) a margin setting method as described in U.S. Pat. No. 6,847,731; and 2) a LINSCAN method (a linear analysis of spectra method) as described in U.S. Provisional Patent Application No. 11/624,067, filed on Jan. 17, 2006, by inventor David L. Frank, and entitled “Method For Determination Of Constituents Present From Radiation Spectra And, If Available, Neutron And Alpha Occurrences”; the collective entire teachings of which being herein incorporated by reference. 
         [0049]    With respect to analysis of collected data pertaining to explosives and/or special materials, the spectral analyzer  240  and the information processing system  212  compare identified possible explosives and/or special materials to the manifest  215  by converting the stored manifest data relating to the shipping container under examination to expected explosives and/or radiological materials and then by comparing the identified possible explosives and/or special materials with the expected explosives and/or radiological materials. If the system determines that there is no match to the manifest for the container then the identified possible explosives and/or special materials are unauthorized. The system can then provide information to system supervisory personnel to alert them to the alarm condition and to take appropriate action. 
         [0050]    The user interface  214 , for example, can present to a user a representation of the collected received returning signals, or the identified possible explosives and/or special materials in the shipping container under examination, or any system identified unauthorized explosives and/or special materials contained within the shipping container under examination, or any combination thereof. 
         [0051]    The data collection system can also be communicatively coupled with a remote control and monitoring system  218  such as via a network  216 . The remote system  218  comprises an information processing system that has a computer, memory, storage, and a user interface  220  such as a display on a monitor and a keyboard, or other user input/output device. The network  216  comprises any number of local area networks and/or wide area networks. It can include wired and/or wireless communication networks. This network communication technology is well known in the art. The user interface  220  allows remotely located service or supervisory personnel to operate the local system  212  and to monitor the status of shipping container verification by the collection of sensor units  201 ,  202  and  292  deployed on the frame structure. An optical scanner system  250  can be remotely operated and allows the remotely located service or supervisory personnel to view an operating environment where the sensors  201 ,  202 ,  292 , are scanning a container or other object under inspection. Additionally, a shipping container tracking system  255  tracks each shipping container and provides container identification information to the local control system  212 . 
         [0052]    Referring to  FIG. 4 , an example of a straddle carrier is shown according to one embodiment of the present invention. The straddle carrier can be positioned over a stack of one or more containers and can efficiently and effectively scan the contents of each container for possible unauthorized and/or hazardous materials.  FIG. 5  illustrates a side view of the straddle carrier showing the primary detector panels and the elevator and secondary detector panels. 
         [0053]    Referring to  FIG. 6 , gamma and neutron detector panels are shown deployed in the center of each side of the straddle carrier, with the gamma detector panels on the inside facing the container and the neutron detector panels on the outside (back-side) of the gamma detector panels. 
         [0054]      FIGS. 7 and 8  illustrate side views of a gamma scanning sensor array panel. These gamma detectors are used primarily for the detection of radiological and or fissile materials with spectral analysis capability.  FIG. 9  shows a side view of multiple gamma scanning sensor array panels. 
         [0055]      FIGS. 10 and 11  illustrate side views of a neutron scanning sensor array panel. These neutron detectors are used primarily for the detection of radiological and or fissile materials with spectral analysis capability.  FIG. 12  shows a side view of multiple neutron scanning sensor array panels. 
         [0056]    Referring to  FIGS. 13 and 14 , a high resolution gamma sensor system can be raised or lowered via an elevator mounted on the self propelled frame structure such as a straddle carrier. A cryocooler system is included with the high resolution gamma sensor system to reduce the sensor operational temperature to a desired level. The sensor-detector housing is made from lightweight composite materials.  FIG. 14  shows a sensor module including a gamma sensor array and a sensor interface unit. Such a sensor module is commercially available from Innovative American Technology Inc., of the United States of America. 
         [0057]    Referring to  FIG. 15 , an example of a radiation source location system using radiation directional finders is shown. NaI detectors, in this example, are deployed in pairs to provide directional indication of the radiation source materials detected. Such radiation directional finders enable the SCRVS to scan a stack of containers and determine which container in the stack of containers contains the detected radiological material(s). Gamma detector data is provided to a spectral analysis system that utilizes a detection process to detect the presence of radiological materials and to determine the particular container that holds such materials. 
         [0058]      FIG. 16  shows an example of the radiation directional finder set used in  FIG. 15 .  FIG. 17  shows test results for directional indication using a pair of directional detector set oriented relative to each other in the 0 degrees and the 90 degrees intervals. A ratio of detector counts between the pair of detectors indicates a direction of the radiation source. At about the 90 degrees mark on the horizontal X-axis of the graph, the bottom line on the graph indicates an all counts ratio from the pair of detectors. This all counts ratio includes both primary impacts of radiation particles with the individual detectors and secondary impacts (i.e., the first impact having been through the other back-to-back detector). The top line, at about the 90 degrees mark on the horizontal X-axis of the graph, indicates a photo-peak counts ratio from the pair of detectors. This photo-peak counts ratio indicates the primary impacts of radiation particles with the individual detectors. A comparison of the two ratios, and knowledge of the physical location and orientation of the pair of directional detector sets, provides an indication of the direction of a radiation source relative to the pair of directional detector sets. By utilizing multiple directional detector sets, such as shown in  FIG. 15 , an information processing system can utilize triangulation analysis, or other direction finding techniques, to effectively pinpoint the location of a radiation source in a detection zone as shown in  FIG. 15 . 
         [0059]    Referring to  FIG. 18 , an example of a sensor rail  901  for horizontal deployment on a straddle carrier or shuttle carrier or other frame structure is shown. The sensor rail  901  includes any combination of gamma detectors  902 , or neutron detectors  903 , or both types of detectors. Also, as illustrated in  FIG. 18 , the sensor rail can be extended or retracted to locate the sensors about a container or other object under inspection. 
         [0060]      FIG. 19  shows an example of a deployment of spreader bar sensors and horizontal rail sensors on a shuttle carrier or straddle carrier or other container movement device. 
         [0061]    By operating the system remotely, such as from a central monitoring location, a larger number of sites can be safely monitored by a limited number of supervisory personnel. 
         [0062]    The preferred embodiments of the present invention can be realized in hardware, software, or a combination of hardware and software. A system according to a preferred embodiment of the present invention can be realized in a centralized fashion in one computer system, or in a distributed fashion where different elements are spread across several interconnected computer systems. Any kind of computer system—or other apparatus adapted for carrying out the methods described herein—is suited. A typical combination of hardware and software could be a general purpose computer system with a computer program that, when being loaded and executed, controls the computer system such that it carries out the methods described herein. 
         [0063]    Various embodiments of the present invention utilize gamma radiation absorption properties of NaI crystals for the directional analysis. Very often different areas of radiation detection equipment meet requirements of locating radiological source. The tasks could be different: location of leaks at nuclear power station, location of hidden dirty bomb in urban environment, or distinguish container with radiological material located in a port. 
         [0064]    The radiation source location system, according to one embodiment of the present invention, consists of multiple detector sets placed within some distance to each other (see  FIG. 15 ). One detector set consist of two Sodium-Iodide (NaI) detectors “sandwiched” together (see  FIG. 16 ). When two NaI detectors are placed next to each other the closest to the radiation source detector will absorb part of gamma rays, so the second detector will have less number of gammas hitting it. By comparing the number of counts in two “sandwiched” detectors system a directional finder can determine an angle to the radiation source. The cross-section of areas determined by two or more detector sets estimates source location, such as shown in  FIG. 15 . 
         [0065]    The following patents are specifically referenced and used as part of the collective teachings herein. 
         [0066]    1) A method and system for analyzing the contents of a container as described in U.S. Pat. No. 7,005,982 entitled “Carrier Security System”, the entire teachings of which being herein incorporated by reference. 
         [0067]    2) A method and system for analyzing the contents of a container as described in U.S. Pat. No. 7,142,109 entitled “Container Verification System for Non-Invasive Detection of Contents”, the entire teachings of which being herein incorporated by reference. 
         [0068]    3) A method and system for analyzing the contents of a container as described in U.S. patent application Ser. No. 11/564,193 entitled “Multi-Stage System For Verification of Container Contents”, the entire teachings of which being herein incorporated by reference. 
         [0069]      4 ) A method and system for analyzing the contents of a container as described in U.S. Pat. No. 7,269,527 entitled “System Integration Module for CBRNE Sensors”, the entire teachings of which being herein incorporated by reference. 
       Non-Limiting Examples 
       [0070]    Although specific embodiments of the invention have been disclosed, those having ordinary skill in the art will understand that changes can be made to the specific embodiments without departing from the spirit and scope of the invention. The scope of the invention is not to be restricted, therefore, to the specific embodiments, and it is intended that the appended claims cover any and all such applications, modifications, and embodiments within the scope of the present invention.