US4514691A — Baggage inspection apparatus and method for deter…

Claim 1

Independent Claim 245 words

Apparatus for conducting baggage inspection for explosives characterized by having a relatively long T 1 and relatively short T 2 , the apparatus comprising: (a) a conveyor system for receiving and moving a bag thereon, the bag to be investigated for explosives above a certain quantity therein; (b) magnet means for forming lines of flux across the path of said conveyor system to intercept baggage thereon for polarizing hydrogen nuclei in the materials of the bag and its contents; (c) coil means for forming a right angle field to the field formed by said magnet at a selected RF frequency for an interval; (d) particle resonance detection circuit means connected to said coil means for determining a signal from materials within the baggage; (e) circuit means connected to said detection means for detecting signals from hydrogen in materials having a long T 1 and short T 2 ; (f) wherein said coil means is comprised of serially located separately connected multiple coils, the coils being separate to inspect different volumes of space along said conveyor system; (g) capacitor means for said coils to form separate tank circuits for each of said coils; (h) switch means connected to said tank circuits for selectively energizing first one and then a second of said tank circuits; (i) pulsed RF power amplifier means for forming a pulse of specified frequency and duration to be transmitted from said coil means wherein the output thereof is applied through said switch means.

Claim 2

Dependent Claim 245 words

Apparatus for conducting baggage inspection for explosives characterized by having a relatively long T 1 and relatively short T 2 , the apparatus comprising: (a) a conveyor system for receiving and moving a bag thereon, the bag to be investigated for explosives above a certain quantity therein; (b) magnet means for forming lines of flux across the path of said conveyor system to intercept baggage thereon for polarizing hydrogen nuclei in the materials of the bag and its contents; (c) coil means for forming a right angle field to the field formed by said magnet at a selected RF frequency for an interval; (d) particle resonance detection circuit means connected to said coil means for determining a signal from materials within the baggage; (e) circuit means connected to said detection means for detecting signals from hydrogen in materials having a long T 1 and short T 2 ; (f) wherein said coil means is comprised of serially located separately connected multiple coils, the coils being separate to inspect different volumes of space along said conveyor system; (g) capacitor means for said coils to form separate tank circuits for each of said coils; (h) switch means connected to said tank circuits for selectively energizing first one and then a second of said tank circuits; (i) pulsed RF power amplifier means for forming a pulse of specified frequency and duration to be transmitted from said coil means wherein the output thereof is applied through said switch means.

Claim 3

Dependent Claim 30 words

The apparatus of claim 1 wherein said magnet means includes a first magnet adjacent to said conveyor system for achieving initial polarization of nuclei in the materials in the bag.

Claim 4

Dependent Claim 25 words

The apparatus of claim 2 including a separate second magnet for forming a second magnetic field parallel to the field formed by said first magnet.

Claim 5

Dependent Claim 46 words

The apparatus of claim 1 wherein said conveyor system includes a first conveyor portion proceeding past said magnet means for initial polarization of baggage on the fly, and includes a second conveyor portion wherein the baggage is held stationary to enable operation of said detection means.

Claim 6

Dependent Claim 67 words

The apparatus of claim 1 wherein said magnet means includes first and second separate magnets arranged to form fields along said conveyor system, and wherein said coil means is at right angles to said second magnet to initiate detection by said detection means of the baggage and its contents within the field of said second magnet and said coil means after initial polarization by said first magnet.

Claim 7

Dependent Claim 86 words

The apparatus of claim 1 wherein said magnet means includes a first magnet for forming a first magnetic field to polarize the materials of the baggage and its contents, and also includes a second magnet located serially along said conveyor system to form a second magnetic field encountered by the baggage and its contents after travelling through the first magnetic field, and further including a booster electromagnet to add to the magnetic field of said second magnet to increase the field intensity by a selected measure.

Claim 8

Dependent Claim 22 words

The apparatus of claim 1 including a metal detector arranged in proximity to said conveyor system for detecting a metal clad bag.

Claim 9

Dependent Claim 235 words

Apparatus for conducting baggage inspection for explosives characterized by having a relatively long T 1 and relatively short T 2 , the apparatus comprising: (a) a conveyor system for receiving and moving a bag thereon, the bag to be investigated for explosives above a certain quantity therein; (b) magnet means for forming lines of flux across the path of said conveyor system to intercept baggage thereon for polarizing hydrogen nuclei in the materials of the bag and its contents; (c) coil means for forming a right angle field to the field formed by said magnet at a selected RF frequency for an interval; (d) particle resonance detection circuit means connected to said coil means for determining a signal from materials within the baggage; (e) circuit means connected to said detection means for detecting signals from hydrogen in materials having a long T 1 and short T 2 ; (f) wherein said circuit means includes timing means for forming a first set of interrogation pulses for said coil means; (g) storage means for receiving and storing a first image from said detection means; (h) storage means for receiving and storing a second image from said detection means; and (i) means for subtracting the first image from the second image to obtain a null indicative that no explosive material is present wherein the explosive is characterized by a long T 1 and a short T 2 .

Claim 10

Dependent Claim 235 words

Apparatus for conducting baggage inspection for explosives characterized by having a relatively long T 1 and relatively short T 2 , the apparatus comprising: (a) a conveyor system for receiving and moving a bag thereon, the bag to be investigated for explosives above a certain quantity therein; (b) magnet means for forming lines of flux across the path of said conveyor system to intercept baggage thereon for polarizing hydrogen nuclei in the materials of the bag and its contents; (c) coil means for forming a right angle field to the field formed by said magnet at a selected RF frequency for an interval; (d) particle resonance detection circuit means connected to said coil means for determining a signal from materials within the baggage; (e) circuit means connected to said detection means for detecting signals from hydrogen in materials having a long T 1 and short T 2 ; (f) wherein said circuit means includes timing means for forming a first set of interrogation pulses for said coil means; (g) storage means for receiving and storing a first image from said detection means; (h) storage means for receiving and storing a second image from said detection means; and (i) means for subtracting the first image from the second image to obtain a null indicative that no explosive material is present wherein the explosive is characterized by a long T 1 and a short T 2 .

Claim 11

Dependent Claim 59 words

The apparatus of claim 8 further wherein said timing means is operated to obtain the second image sufficiently close after the first image that the hydrogen materials in explosives having a long T 1 do not have sufficient time to be repolarized prior to the second image wherein the hydrogen forms a different resonant response in the second image.

Claim 12

Dependent Claim 63 words

The apparatus of claim 9 wherein said magnet means is operated for a sufficient interval at a sufficient intensity to polarize bound hydrogen materials having a long T 1 and short T 2 , and said timing means initiates the formation of the second image at a time after formation of the first image sufficiently short that T 1 repolarization is not accomplished.

Claim 13

Dependent Claim 263 words

Apparatus for conducting baggage inspection for explosives characterized by having a relatively long T 1 and relatively short T 2 , the apparatus comprising: (a) a conveyor system for receiving and moving a bag thereon, the bag to be investigated for explosives above a certain quantity therein; (b) magnet means for forming lines of flux across the path of said conveyor system to intercept baggage thereon for polarizing hydrogen nuclei in the materials of the bag and its contents; (c) coil means for forming a right angle field to the field formed by said magnet at a selected RF frequency for an interval; (d) particle resonance detection circuit means connected to said coil means for determining a signal from materials within the baggage; (e) circuit means connected to said detection means for detecting signals from hydrogen in materials having a long T 1 and short T 2 ; (f) wherein said magnet means is comprised of first and second separate magnets spaced serially along said conveyor system; (g) magnetic field intensity sensor means deployed within the field formed by said first magnet from measuring the intensity of the field impinging on the baggage and its contents; (h) magnetic field regulator means connected to said field sensor means; and (i) magnet power supply means operated by said magnetic field regulator means for forming a variable current applied to said second magnet for altering the magnetic field intensity formed by said second magnet to obtain a specified field intensity in the second field dependent in part on the measurement of said field intensity sensor means.

Claim 14

Dependent Claim 263 words

Apparatus for conducting baggage inspection for explosives characterized by having a relatively long T 1 and relatively short T 2 , the apparatus comprising: (a) a conveyor system for receiving and moving a bag thereon, the bag to be investigated for explosives above a certain quantity therein; (b) magnet means for forming lines of flux across the path of said conveyor system to intercept baggage thereon for polarizing hydrogen nuclei in the materials of the bag and its contents; (c) coil means for forming a right angle field to the field formed by said magnet at a selected RF frequency for an interval; (d) particle resonance detection circuit means connected to said coil means for determining a signal from materials within the baggage; (e) circuit means connected to said detection means for detecting signals from hydrogen in materials having a long T 1 and short T 2 ; (f) wherein said magnet means is comprised of first and second separate magnets spaced serially along said conveyor system; (g) magnetic field intensity sensor means deployed within the field formed by said first magnet from measuring the intensity of the field impinging on the baggage and its contents; (h) magnetic field regulator means connected to said field sensor means; and (i) magnet power supply means operated by said magnetic field regulator means for forming a variable current applied to said second magnet for altering the magnetic field intensity formed by said second magnet to obtain a specified field intensity in the second field dependent in part on the measurement of said field intensity sensor means.

Claim 15

Dependent Claim 38 words

The apparatus of claim 11 further including timing means connected to a transmitter pulse forming means for forming a procession of pulses to be transmitted through said coil means, and wherein said pulses are spaced and timed pulses.

Claim 16

Dependent Claim 43 words

The apparatus of claim 12 wherein said transmitted pulses are supplied through a transmit and receive circuit means to said coil means, and wherein said detection means is connected through said transmit and receive circuit means to observe responses from said coil means.

Claim 17

Dependent Claim 31 words

The apparatus of claim 11 including memory means connected to said circuit means for receiving and storing sequentially obtained echoes observed at said coil means from materials within said coil means.

Claim 18

Dependent Claim 71 words

The apparatus of claim 11 wherein said magnet means is operated in a field intensity to initiate polarization of hydrogen in explosive compounds characterized by a long T 1 and a short T 2 and also at a level to achieve nuclear quadrature resonance with nitrogen in such explosives to initiate an energy transfer from the nitrogen to the hydrogen to thereby shorten the time required for polarization of the hydrogen.

Claim 19

Dependent Claim 46 words

The apparatus of claim 11 wherein said conveyor system includes a first conveyor portion proceeding past said magnet means for initial polarization of baggage on the fly, and includes a second conveyor portion wherein the baggage is held stationary to enable operation of said detection means.

Claim 20

Dependent Claim 22 words

The apparatus of claim 11 including a metal detector arranged in proximity to said conveyor system for detecting a metal clad bag.

Claim 21

Independent Claim 164 words

A method of detecting explosives in baggage and the contents thereof comprising the steps of: (a) passing the baggage through a first magnetic field to obtain polarization of hydrogen nuclei; (b) placing the baggage in a second magnetic field after polarization; (c) transmitting RF pulse energy into the baggage in the second field to initiate an NMR response; (d) receiving the NMR response; (e) storing the received NMR response to comprise a first image; (f) repeating the step of transmitting RF pulse energy into the baggage to obtain a second NMR response; wherein the second NMR response is obtained so rapidly after the first NMR response that materials having a long T 1 do not have sufficient time to polarize; (g) storing the second NMR response to comprise a second image; (h) subtracting one of the images from the other to obtain a difference between the two images; and (i) evaluating the obtained difference for a null indicative of no explosives in the baggage.

Claim 22

Independent Claim 164 words

A method of detecting explosives in baggage and the contents thereof comprising the steps of: (a) passing the baggage through a first magnetic field to obtain polarization of hydrogen nuclei; (b) placing the baggage in a second magnetic field after polarization; (c) transmitting RF pulse energy into the baggage in the second field to initiate an NMR response; (d) receiving the NMR response; (e) storing the received NMR response to comprise a first image; (f) repeating the step of transmitting RF pulse energy into the baggage to obtain a second NMR response; wherein the second NMR response is obtained so rapidly after the first NMR response that materials having a long T 1 do not have sufficient time to polarize; (g) storing the second NMR response to comprise a second image; (h) subtracting one of the images from the other to obtain a difference between the two images; and (i) evaluating the obtained difference for a null indicative of no explosives in the baggage.

Claim 23

Dependent Claim 45 words

The method of claim 18 further including the step of initially polarizing hydrogen nuclei in the baggage, then obtaining the first NMR response and simultaneously depolarizing the hydrogen nuclei; repolarizing hydrogen nuclei having a short T 1 , and then obtaining the second NMR response.

Claim 24

Dependent Claim 23 words

The method of claim 18 including the step of evaluating the obtained difference for explosive indicated by differences exceeding a selected threshold value.

Claim 25

Dependent Claim 43 words

The method of claim 20 including the step of spacing the steps of transmitting the RF pulses sufficiently close that long T 1 materials in the baggage do not polarize prior to the second step of transmitting RF pulse energy into the baggage.

Claim 26

Dependent Claim 108 words

The method of claim 18 including the step of first polarizing in a magnetic field intensity at an elevated intensity; (a) thereafter changing the magnetic field intensity to a different intensity, the different intensity being determined by that intensity to obtain energy transfer from nitrogen in explosive compounds made of hydrogen and nitrogen, the transfer achieving polarization of the hydrogen in such compounds more rapidly then that indicated by the T 1 of such hydrogen; and (b) then obtaining first and second NMR responses from the hydrogen wherein the first response is accomplished with polarized hydrogen in such explosives and the second response is obtained without substantial polarization.

Claim 27

Dependent Claim 19 words

The method of claim 22 wherein nitrogen nuclear quadrupole resonance polarity is achieved prior to decreasing the field intensity.

Claim 28

Dependent Claim 27 words

The method of claim 18 including the step of obtaining both of said NMR responses in timed sequence after the baggage is polarized in a magnetic field.

Claim 29

Independent Claim 117 words

A method of distinguishing hydrogen in compounds in baggage to detect explosive compounds of hydrogen characterized by a long T 1 and short T 2 and to distinguish other compounds of hydrogen having a long T 1 and long T 2 comprising the steps of: (a) polarizing hydrogen nuclei in a magnetic field; (b) transmitting a sequence of RF pulses into the baggage at right angles to the polarizing field to form first and subsequent NMR echos from the baggage; and (c) observing the subsequent NMR echos to distinguish long T 1 , long T 2 hydrogen materials by a larger subsequent echo compared to the echo from a long T 1 , short T 2 material.

Claim 30

Independent Claim 117 words

A method of distinguishing hydrogen in compounds in baggage to detect explosive compounds of hydrogen characterized by a long T 1 and short T 2 and to distinguish other compounds of hydrogen having a long T 1 and long T 2 comprising the steps of: (a) polarizing hydrogen nuclei in a magnetic field; (b) transmitting a sequence of RF pulses into the baggage at right angles to the polarizing field to form first and subsequent NMR echos from the baggage; and (c) observing the subsequent NMR echos to distinguish long T 1 , long T 2 hydrogen materials by a larger subsequent echo compared to the echo from a long T 1 , short T 2 material.

Claim 31

Dependent Claim 222 words

Apparatus for conducting baggage inspection for explosives characterized by having a relatively long T 1 and relatively short T 2 , the apparatus comprising: (a) a conveyor system for receiving and moving a bag thereon, the bag to be investigated for explosives above a certain quantity therein; (b) magnet means for forming lines of flux across the path of said conveyor system to intercept baggage thereon for polarizing hydrogen nuclei in the materials of the bag and its contents; (c) coil means for forming a right angle field to the field formed by said magnet at a selected RF frequency for an interval; (d) particle resonance detection circuit means connected to said coil means for determining a signal from materials within the baggage; (e) circuit means connected to said detection means for detecting signals from hydrogen in materials having a long T 1 and short T 2 ; (f) means for digitizing signals from said circuit means; (g) digital storage means for storing digital data from said digitizing means; (h) timing means operating an RF pulse forming means to form first and second identical RF pulse trains supplied to said coil means; and (i) means for subtracting the digitized responses to the first and second RF pulse trains to obtain a null indicative of no long T 1 materials in the baggage.

Claim 32

Dependent Claim 222 words

Apparatus for conducting baggage inspection for explosives characterized by having a relatively long T 1 and relatively short T 2 , the apparatus comprising: (a) a conveyor system for receiving and moving a bag thereon, the bag to be investigated for explosives above a certain quantity therein; (b) magnet means for forming lines of flux across the path of said conveyor system to intercept baggage thereon for polarizing hydrogen nuclei in the materials of the bag and its contents; (c) coil means for forming a right angle field to the field formed by said magnet at a selected RF frequency for an interval; (d) particle resonance detection circuit means connected to said coil means for determining a signal from materials within the baggage; (e) circuit means connected to said detection means for detecting signals from hydrogen in materials having a long T 1 and short T 2 ; (f) means for digitizing signals from said circuit means; (g) digital storage means for storing digital data from said digitizing means; (h) timing means operating an RF pulse forming means to form first and second identical RF pulse trains supplied to said coil means; and (i) means for subtracting the digitized responses to the first and second RF pulse trains to obtain a null indicative of no long T 1 materials in the baggage.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1988-04-29	1988-10-29	1989-04-30	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1992-04-29	1992-10-29	1993-04-30	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1996-04-29	1996-10-29	1997-04-30	$7700.00	Window Closed / Lapsed

Baggage inspection apparatus and method for determining presences of explosives

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