Abstract:
A fully integrated portable screening system includes a main housing and a contact pad. The contact pad is removably positioned in the main housing and covered by at least one sample sheet. The contact pad is preferably constituted by a cylindrical baton which carries a roll of sample collection sheets. A test subject interacts with the contact pad, leaving a trace sample on the sample collection sheet. The contact pad is then placed within the main housing and the trace sample is exposed to a test medium designed to interact with a specific analyte of interest potentially present in the trace sample. After exposure to the test medium, the sample sheet is subjected to a testing mechanism which exposes any interaction between the test medium and the analyte of interest to produce a test result.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/723,433 filed Oct. 5, 2005 entitled “Compact, Portable Screening System For Trace Threat Materials.” 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention pertains to the art of screening systems and, more particularly, to a fully integrated portable screening system capable of scanning for various analytes of interest, such as explosives and other trace compounds. 
     2. Discussion of the Prior Art 
     Since Sep. 11, 2001, protection against terrorist threats has become a national priority. This priority extends from the protection of government facilities inside the U.S. and abroad to the protection of private businesses and venues. Various types of threats have been postulated, including attacks using explosives, chemical and/or biological agents and nuclear and radiological agents (dirty bombs). The diversity of these threats has created a number of complex security challenges for national, state, and local governments, the transportation industry, private businesses, and even individuals. Total expenditures related to Homeland Security topped $100B in 2003 and billions more have been allocated in Federal, Supplemental Appropriations and State/Local spending. Increasingly, U.S. businesses are devoting more revenue to security systems, with total expenditures reaching tens of billions of dollars. Growth in the homeland security industry is expected to be vigorous over the next decade. Motivated by the wide diversity of potential threats and by the inadequacy of currently available systems, government investments in research and development are on the rise. 
     Of the various potential threats, explosives remain the number one choice of most terrorists. Indeed, many experts have noted that, in the case of terrorist activity, compelling statistical evidence indicates that bombs are a primary threat. The pernicious and prevalent nature of this threat has been observed in recent attacks on military, civilian and private sector targets. In particular, bombs, or improvised explosive devices (IEDs), have become a major threat to U.S. military operations. IED attacks against U.S. and coalition led forces in Iraq have been responsible for more military and civilian casualties than any other single weapon. The diversity, deadliness and increasingly prevalent use of IEDs in such conflicts highlight the low risk and high payoff nature of the weapon. Notably, most of the currently proposed methods for combating this threat involve systems that attempt to detect the IED after deployment. This is the least optimum time to deal with the threat as the signature of the IED and the vulnerability of the enemy is never lower than after the IED has been deployed. Further, the technical demands on such systems are increasingly high, environmental clutter creates unacceptably high false alarm rates. Moreover, once an IED is deployed, the probability of detection must be near perfect. Thus, there is a compelling need for systems that can detect bombers, bomb makers and bomb making factories in these diverse settings prior to the deployment of the weapon. In order to be most effective, the systems should be portable, inexpensive and easy to use. 
     Most currently available explosive detection methods involve costly, large, fixed base and low throughput systems. Current systems can cost more than one million dollars per portal for bulk explosive detection and tens of thousands of dollars for trace explosive detection. Indeed, these systems are so costly and operator intensive that they are of limited utility for widespread distributed operations and are therefore most often used at choke points or portals. Existing and recently developed systems, which were designed to increase portability, are expensive and power intensive. Perhaps more importantly, these systems were not designed with the primary purpose of detecting bombers, bomb makers and bomb making factories, the detection of which would have a far greater impact on the overall use of IEDs than finding any single device. 
     Existing systems are designed to detect vapor emanating from explosives or traces of explosives rather than the direct detection of explosive particulates. As explosives have very low vapor pressures, the vapor signature emanating from an explosive can be exceedingly small thus driving systems to ultra-high sensitivity requirements which result in significant false alarm rates. In some cases, heating is required to create an increased vapor signature. In order to identify bombers and bomb makers, a detection system should be focused on sampling methods that maximize the probability of identifying individuals that have been in extensive contact with explosives or in explosive contaminated areas. 
     In summary, currently available screening systems, in particular, explosive screening systems, suffer from many disadvantages, such as high cost, low throughput, high false alarm rates, operational complexity high maintenance and training requirements, poorly designed sampling methods, high power requirements and the like. In addition, these systems are most typically designed to identify the bomb itself, not the bombers or the bomb maker. They are expensive and cumbersome, thereby not being well-suited for deployment in a wide variety of field settings. These limitations have created a significant barrier to conducting widespread explosive screening which is necessary to combat the threat. 
     Based on the above, there is a great and urgent need for a deployable, portable and low cost screening system having a sampling system designed to detect trace contamination on people and objects associated with certain people, while being capable of use in a variety of field settings. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a fully integrated portable screening system for detecting analytes of interest on individuals or objects. The screening system includes a main housing and a contact pad. The contact pad is removably positioned in the main housing and covered by at least one sample collection sheet. The contact pad is preferably constituted by a cylindrical baton which carries a roll of individual, single use sample collection sheets. In any event, after a subject either, an individual or an object, interacts with the contact pad, leaving a trace sample on the sample collection sheet, the contact pad is placed within the main housing and the trace sample is exposed to a test medium designed to interact with a specific analyte of interest potentially present in the trace sample. After exposure to the test medium, the sample sheet is subjected to a testing sequence which exposes any interaction between the test medium and the analyte of interest to produce a test result. 
     In accordance with the testing sequence of the invention, the test medium, preferably in the form of a photoluminescent compound, is sprayed onto the sample collection sheet. The photoluminescent compound is formulated to interact with, for example, explosive residue or another analyte of interest. When exposed to light at particular wavelengths, the analyte of interest either quenches luminescence or becomes luminescent. One, two or more distinct test mediums can be sprayed individually or sequentially onto the sample collection sheet depending upon the particular analyte(s) of interest. After exposing the sample collection sheet to the test medium(s), the operator simply activates a test mechanism and peers through a view port provided on the main housing to determine whether an analyte of interest is present in the trace sample. 
     In further accordance with the invention, the portable screening system includes a cueing system that indicates a need for system calibration. More specifically, periodically, such as after conducting a predetermined number of tests, the cuing system alerts the operator that the device should be calibrated. In the most preferred embodiment of the invention, one of the sample sheets includes a marker indicating a need for system calibration. That is, the sample sheets are provided on a roll or sheet feeder that allows continued use of the screening system. The roll of sample sheets is provided in a disposable sheath that protects the sample sheets from contamination and also enables operators to readily re-load additional sample sheets into the threat screening system while in the field. In any event, as sample sheets are used, the roll diminishes and one of the sheets is provided with a visual marker indicating a need for calibration. For example, one in every one hundred sample sheets can include the visual marker. During calibration, a test strip or calibration pen/marker containing the analyte of interest is applied to the sample sheet and subjected to the scanning process to ensure that the system is operating properly. 
     Additional objects, features and advantages of the present invention will become more readily apparent from the following detailed description of preferred embodiments when taken in conjunction with the drawings wherein like reference numerals refer to corresponding parts in the several views. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front right perspective view of a fully integrated portable screening system constructed in accordance with the present invention; 
         FIG. 2  is a rear perspective view of the screening system of  FIG. 1 ; 
         FIG. 3  is a bottom view of the screening system of  FIG. 1 ; 
         FIG. 4  is an exploded view of a contact pad shown in the form of a baton employed in connection with the screening system constructed in accordance with the present invention; 
         FIG. 5  is a cut-away view illustrating internal components of the portable screening system constructed in accordance with the present invention; 
         FIG. 6  is a left side, cut-away view of the portable screening system; and 
         FIG. 7  is a left side cut-away view of the present invention illustrating an operating mechanism employed to simultaneously release a test medium and rotate the baton of  FIG. 2  to ensure substantially complete coverage of a sample collection sheet. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With initial reference to  FIGS. 1-3 , a self contained, fully integrated, portable screening system for determining whether a subject has been in contact with a particular analyte of interest is generally indicated at  2 . By portable, it should be understood that the present invention is a small (no larger than a briefcase) light unit that is readily transportable and deployable by a single individual operator. In any event, screening system  2  includes a main housing  4  having a top wall  6 , a bottom wall  7 , a front wall  8 , a rear wall  9  and opposing side walls  10  and  11 . Actually, main housing  4  is formed from first and second housing halves  12  and  13  that are joined through a plurality of mechanical fasteners (not separately labeled) arranged at various locations along top, bottom, and opposing walls  6 ,  7 ,  10  and  11 . Main housing  4  is basically divided into three zones, namely an upper zone  20 , an intermediate zone  22  and a lower zone  24 . As will be detailed more fully below, upper zone  20  contains a sample collection device, intermediate zone  22  includes a reagent application system and lower zone  24  provides storage and internal access zones for screening system  2 . In any event, first and second handles  30  and  31  are provided on opposing side walls  10  and  11  to enable an operator to readily grasp and operate portable screening system  2 . 
     As best shown in  FIGS. 2 and 6 , screening system  2  is provided with a toolbox  35  that can preferably house various tools or other items, such as a screwdriver, a lens cleaning cloth, calibration media and the like. Toolbox  35  includes a cover  37  that is hingedly mounted to rear wall  9  through a hinge element  38  ( FIG. 6 ). Below cover  37  is a second or reagent access cover  39  that is pivotally mounted to bottom wall  7  through a hinge element  46 . As will be discussed more fully below, reagent access cover  39  is selectively opened to replenish reagent in intermediate zone  22 . Arranged above toolbox  35  is a power switch  44  and below toolbox  35 , on bottom wall  7 , is arranged a battery compartment  47  (see  FIGS. 3 and 6 ). Battery compartment  47  includes a battery cover  48  that selectively provides access to a plurality of batteries, one of which is indicated at  50  in  FIG. 6 , which provide the necessary power for screening system  2 . 
     Referring back to  FIG. 1 , screening system  2  includes an indicator panel  60  provided on front wall  8 . Indicator panel  60  includes a plurality of LEDs  62 - 66  that provide visual information to the operator. For example, LED  62  is illuminated to indicate when power is on, LED  63  is illuminated to provide a low battery warning and indicator lights  64 - 66  are associated with particular reagents or test mediums being employed to test a sample. As will be discussed more fully below, in order to choose a particular reagent, an operator rotates a selector switch  73  (see  FIG. 2 ) provided on rear wall  9 . In a manner that will also be discussed more fully below, following application of the medium, the operator activates a view switch  80  provided on front wall  8  to activate a testing mechanism which reveals a test result. Preferably, the operator peers through a view finder  84  in order to view the test result. 
     In accordance with the invention, portable screening system  2  employs a contact pad or baton  94  to obtain a trace sample which potentially contains an analyte of interest from a subject. To obtain a sample, an individual is asked to grasp baton  94 , alternatively, baton  94  can be rolled or brushed across an object to obtain a trace sample. As best shown in  FIG. 4 , baton  94  includes a first end or handle  97  that extends to a second end  98  through an intermediate portion or media core  100 . Media core  100  is designed to snuggly receive a sample collection sheet roll  103  which includes a plurality of individual single collection sheets, one of which is indicted at  104 , secured to baton  94  through use of a clamping unit such as a washer  106  and a mechanical fastener  107 . After each screening, the used sample collection sheet is removed to expose a new, pristine sample collection sheet  104  for a subsequent testing procedures. Preferably, each sample collection sheet  104  is coated with a tacky adhesive that retains trace residue and any potential analytes of interest obtained from the subject. In addition, each sample collection sheet can be provided with a surfactant or catalyst, such as zinc powder, is that enhances analyte detection. In any case, baton  94  includes an interface section  110  arranged proximate to handle  97 . Interface section  110  is preferably provided with a plurality of spring clips  112  which, as will be discussed more fully below, engage a sheath  115  ( FIG. 5 ) provided in upper zone  20  of portable screening system  2 . Sheath  115  is operatively associated with a crank handle  121  having a gripping portion  122 . Crank handle  121  is rotated following a sample collection stop to activate an operating mechanism  125  to initiate a screening process. 
     In further accordance with the invention, after obtaining a trace sample from a test subject, the sample collection sheet is exposed to a test medium(s) or activating solution(s) which is formulated to interact with particular analytes of interest. As best shown in  FIGS. 5 and 6 , portable screening system  2  includes a reagent or solution application system  141  arranged substantially within intermediate zone  22 . Application system  141  includes a plurality of solution containers  142 - 144  which store one or more test mediums under pressure. Containers  142 - 144  are inserted into intermediate zone  22  through reagent access cover  39 . In any event, the test medium is preferably a photoluminescent compound which is converted to aerosol form and delivered onto sample collection sheet  104 . More specifically, each solution container  142 - 144  includes a corresponding receptacle or containing portion  147 - 149  that stores a test medium in liquid form and an outlet or primary valve  153 - 155  that is fluidly connected to a central manifold  158 . Central manifold  158  includes a secondary valve  163  controlled by a metering pin  164 . Metering pin  164  controls how much test medium is directed through a nozzle  167 . In order to choose from which container the test medium is released, the operator selectively rotates selector switch  73  to a desired position which corresponds to one of containers  142 - 144 . 
     More specifically, nozzle  167  is operatively associated with a solenoid  170  that, upon receiving a dispensing command, opens secondary valve  163  causing the test medium to exit from nozzle  167  in an atomized or aerosol form, with the spray being directed onto sample collection sheet  104 . Preferably, the spray of solution is cone-shaped having a base diameter of approximately three inches or more. In this manner, sample collection sheet  104  is substantially, completely coated with test medium. In order to more completely coat sample collection sheet  104  with test medium, baton  94  is rotated during the spraying operation. 
     In still further accordance with the invention, after inserting baton  94  into sheath  115 , view switch  80  blinks red to indicate that sample collection sheet  104  is positioned and ready for the application of test medium. Towards that end, the operator rotates crank handle  121  to initiate operating mechanism  125 . Operating mechanism  125  includes a rotary shaft  190  operatively connected to crank handle  121 . Rotary shaft  190  extends through and is connected with a cam unit  193  and a torsion spring  196 . Cam unit  193  includes a cam lobe (not labeled) that engages a switch  199  configured to activate solenoid  170  to release the test medium onto sample collection sheet  104 . More specifically, after rotating crank handle  121  approximately one-quarter turn to load torsion spring  196 , gripping portion  122  is released causing crank handle  121  to return to a home or initial position through application of a biasing force supplied by torsion spring  196 . As crank handle  121  returns to the home position, rotary shaft  190  rotates cam unit  193 , causing the cam lobe to engage with switch  199  and solenoid  170  to be activated in order to release the test medium onto sample collection sheet  104 . As stated above, as the solution is released, baton  94  rotates within sheath  115 , ensuring complete coverage of sample collection sheet  104  in a manner that will be detailed more fully below. 
     As best shown in  FIGS. 5 and 7 , rotary shaft  190  is operatively connected to a first or drive pulley  210 . Drive pulley  210  is connected to an inner hub  213  of a second pulley  214  by a first belt  217 . An outer hub  219  of second pulley  213  is connected to a third or driven pulley  220  through a second belt  225 . Third pulley  220  is coupled to interface section  110  of baton  94  through spring clips  112  such that any movement of third pulley  220  is directly transferred to baton  94 . The preferred configuration provides a 4:1 ratio between drive pulley  210  and driven pulley  220 . In this manner, one quarter turn of crank handle  121  results in one complete revolution of baton  94 . Thus, releasing crank handle  121 , as discussed above, not only results in activating switch  199  but also causes baton  94  to undergo one complete reverse revolution which ensures that sample collection sheet  104  is substantially fully coated with test medium. 
     Following application of the test medium, a dryer unit  235  is activated to rapidly dry sample collection sheet  104 . Dryer unit  235  includes a fan  236  that directs air through an intake port  238  onto baton  94  to dry sample collection sheet  104 . At this point, it should be noted that dryer unit  235  could employ a heater or a combination heater and fan to dry sample collection sheet  104 . During operation of dryer unit  235 , an exhaust fan  242 , located in lower zone  24 , is operated to guide air out from portable screening system  2  through an exhaust port  243 . Prior to exiting exhaust port  243 , exhaust air passes through a filter  247 . Filter  247  employs charcoal or the like to remove foreign particles and/or residual test medium from the exhaust air. The operation of dryer unit  235  and exhaust fan  242  is established by a control board  250  which also provides a signal to the operator that sample collection sheet  104  is dry and the sample is ready for viewing. 
     More specifically, after sample collection sheet  104  is dry, view switch  80  changes from red to green indicating that the sample is ready for viewing. At this point, the operator peers through view finder  84  and presses view switch  80  to activate a testing mechanism, preferably in the form of a light source  270  most preferably in the form of an ultraviolet light source. Light source  270  passes through a UV filter lens  275  and bathes sample collection sheet  104  in light. Preferably, light source  270  is constituted by a 380 nm cold cathode tube. In any event, if the subject has handled or been in contact with the analyte of interest, the solution sprayed onto sample collection sheet  104  will cause trace particles of the analyte obtained from the subject to quench luminescence or create luminescence providing a test result that is viewed by the operator through view finder  84 . Portable screening system  2  can be reconfigured to screen from numerous analytes of interest by simply changing light source  270  and/or the test medium. 
     At this point, it should be readily understood that the portable screening system constructed in accordance with the present invention provides for a simple, easily transportable method of testing individuals for contact with analytes of interest. In order to enhance detection levels, is portable screening system  2  can be readily calibrated at periodic intervals. For example, a visual cue  270  can be provided to the operator on, for example, one of sample sheets  104 . As sample sheets are used, roll  103  diminishes and one of the sample sheets  104  provided with visual marker or cue  270  that becomes exposed. For example, one in every one hundred sheets can include visual cue  270 . When cue  270  appears, the operator simply applies a calibration media containing the analyte of interest to the sample collection sheet. Once applied, the baton is inserted into sheath  115  and the sample sheet is analyzed in the manner described above. The results should indicate the presence of the test substance. If not, screening system  2  would require servicing. Visual cue  270  could also be presented as a separate LED on indicator panel  60 . 
     In any case, the portable screening system of the present invention enables rapid and accurate scanning of numerous individuals and objects under field conditions without requiring expensive support systems typically required. Although described with reference to a preferred embodiment of the invention, it should be readily understood that various changes and/or modifications can be made to the invention without departing from the spirit thereof. For instance, the portable screening system can be incorporated into a briefcase-like device with contact pad  97  being substantially planar. In addition, various light sources employing different wavelengths can be employed depending on the particular analytes of interest and/or test medium. For that matter, the test medium can be varied depending upon the particular analyte of interest. Furthermore, the application process can be varied to release one or more diverse test mediums sequentially or simultaneously depending upon current circumstances. In general, the invention is only intended to be limited by the scope of the following claims.