EP0924967A2 - Verfahren und Vorrichtung zur vielfach-Energie Abtastung - Google Patents

Verfahren und Vorrichtung zur vielfach-Energie Abtastung Download PDF

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Publication number
EP0924967A2
EP0924967A2 EP98120060A EP98120060A EP0924967A2 EP 0924967 A2 EP0924967 A2 EP 0924967A2 EP 98120060 A EP98120060 A EP 98120060A EP 98120060 A EP98120060 A EP 98120060A EP 0924967 A2 EP0924967 A2 EP 0924967A2
Authority
EP
European Patent Office
Prior art keywords
ray
beams
rays
detecting
source
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP98120060A
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English (en)
French (fr)
Other versions
EP0924967A3 (de
Inventor
Daniele Radogna
Mauro Gambaccini
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Gilardoni SpA
Original Assignee
Gilardoni SpA
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Filing date
Publication date
Application filed by Gilardoni SpA filed Critical Gilardoni SpA
Publication of EP0924967A2 publication Critical patent/EP0924967A2/de
Publication of EP0924967A3 publication Critical patent/EP0924967A3/de
Withdrawn legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05G—X-RAY TECHNIQUE
    • H05G1/00—X-ray apparatus involving X-ray tubes; Circuits therefor
    • H05G1/08—Electrical details
    • H05G1/64—Circuit arrangements for X-ray apparatus incorporating image intensifiers

Definitions

  • the present invention relates to a device and a method for multienergy scanning, based on the production and detection of X rays, to form images and detect differences in the materials of the object examined.
  • the invention is particularly suitable in the security field for inspection of both hand and hold luggage, postal parcels or cargo. Moreover, it can be used in the medical-scientific field to examine a biological entity, be it a person or an animal; in the ecological field to examine refuse or used containers, in the food sector, when the object to be examined consists of packaged or unpackaged foodstuffs.
  • So-called multienergy scanning systems are devices based on the production and detection of X rays which, besides being able to provide a black and white image in which each pixel of the digital image obtained has a gray value which is a function of the radiolucency of the object targeted, provide an image, generally in false colours, in which the pixel value expresses a certain classification of the composition of the materials x-rayed.
  • the algorithms employed on these systems to distinguish such substances are based on processing of the data entered, which include at least a pair of register images of the same object each of which is made by reading the radiation incident on the detection system having a different spectral quality of the X-rays.
  • the difference in the spectral quality is evaluated quantitatively after the radiation has interacted with the target and then from the results of this estimate the aforementioned algorithms move to determine the composition of the materials through with the radiation passes which, normally but not necessarily, can be expressed in terms of mean atomic number.
  • the quality of the register images is critical not only for the purposes of an appreciable and informative display for an operator who must evaluate the nature of said image, recognizing, for example, the presence of objects or artefacts to which attention must be paid, but also as regards the use of the algorithms that must extract the information on the composition of the materials.
  • U.S. patent 4.626.688 discloses the use of a detection system based on a double array of solid state detectors placed one on top of the other which are in register and are separated by a filter of special material.
  • the filter attenuates the lower-energy components of the incident spectrum, differentiating the readings of the double array of detectors.
  • the array of detectors situated upstream of the filter reads the low-energy component of the spectrum and the array of detectors situated downstream of the filter reads the high-energy component of the spectrum.
  • GB 2 287 164 describes a configuration that uses a system, such as a conveyor belt for example, that enables the object to be examined, commonly called the target, to be moved linearly, and two pairs of spatially separated detection/source systems, in which the two sources, consisting of radiogenic tubes, are fed at different voltages.
  • the two arrays of detectors at different times read a radiation that passes through the same region of the target produced with a different emission spectrum at the origin.
  • the array of detectors corresponding to the source fed at high voltage will read the high-energy spectrum, whilst the row of detectors corresponding to the source fed at low voltage will read the low-energy spectrum.
  • FR 2 705 791 describes a configuration that uses a type of detector intrinsically capable of discriminating the content of the incident radiation in energy.
  • the single detector is made of a single silicon crystal with various layers; since high-energy photons penetrate silicon to a greater extent that low-energy photons, the spectrum composition of the object explored with the rays is reconstructed from the readings performed in the various layers of the detector.
  • the object of the invention is to eliminate said drawbacks providing a device and a method capable of enhancing the quality of the images, so as to be able to draw adequate conclusions on the composition of the materials.
  • the intrinsic correlation between the spectra of the signals is minimized.
  • different images are created by making incident on the same target X-ray beams obtained by selecting appropriately restricted energy bands of the emission spectrum of a beam coming from a radiogenic tube.
  • the X-ray beams incident on the target not only are of different quality, but also, to all effects, by interacting on the material to be inspected, they test its radio-opacity characteristics at different energies that are well separated from each other.
  • the device according to the invention substantially comprise:
  • An X-ray source preferably a radiogenic tube 1, emits a polychromatic X ray beam 2 or any beam of rays produced within a voltage range of 140-150 kV.
  • the polychromatic beam 2 is mad to pass through a first primary collimator 3 which has three through cavities 4, 5 and 6 from which three polychromatic beams 7, 8 and 9, respectively, can emerge.
  • the X-ray beam 7 is directed on a first crystal monochromator 10.
  • Crystals monochromators are mosaic crystal structures having such a crystal lattice as to obtain Bragg's diffraction of the incident X-ray beam.
  • ⁇ is the angle of incidence of the X-ray beam
  • ⁇ is the wavelength of the X-ray beam
  • a is the pitch of the crystal monochromator lattice
  • k (1,2,3, 7) is an integer number that represents the order of diffraction.
  • the electromagnetic waves of the X-ray bean are summed constructively in the direction given by Bragg's relation (1) and destructively in all other directions.
  • the beam 9 is incident on a second crystal monochromator 11, with an inclination ⁇ ' different from (greater than) the inclination ⁇ between the beam 7 and the crystal 10.
  • the angle of incidence ⁇ ' is selected so as to obtain a monochromatic low-energy beam c .
  • the beams a, 8, c are made to pass respectively through 3 through cavities 12,13,14 made in a second primary collimator 15. Emergent from the cavity 12 is the high-energy monochromatic beam a ; emergent from the cavity 13 is a polychromatic high-energy beam b ; emergent from the cavity 14 is the monochromatic low-energy beam c.
  • Said three beams a,b,c are incident on a conveyor belt 17 on which an object for inspection 18 advances.
  • Beneath the conveyor belt 17 is positioned a secondary collimator 19, in which there are three through cavities 20, 21, 22 destined respectively to allow the beams a, b, c to pass.
  • Beneath the cavity 20 is situated a first array of solid state detectors 23, able to detect the high-energy radiation coming from the monochromatic beam a .
  • Beneath the cavity 22 is positioned a second array of solid state detectors 25 able to detect the radiation coming from the low-energy monochromatic beam c .
  • Beneath the cavity 21 is positioned a third array of solid state detectors 24, able to detect the radiation coming from the high-energy polychromatic beam b .
  • the output from the arrays of detectors 23, 24, 25 is transmitted, in a substantially known manner, to a multiplex 26 which selects a voltage signal to transmit to an integrator 27 which can consist of an operational amplifier configured as an integrator.
  • the signal emergent from the integrator 27 is transmitted to a sampling circuit 28 which can consist of a sample and hold circuit.
  • the analog signal sampled is passed through an image correcting unit 29 which makes a correction to the gain variations due to the preceding stages.
  • the signal emerging from the image corrector 29 is transmitted to an anolog-to-digital converter 30 which translates the analog signal into a digital signal, then the digital signal is stored in a memory 31.
  • the signal resident in the memory 31 is picked up by a video output circuit 32 where the images to be sent to a monitor 33 are reconstructed.
  • This monitor 33 has a phosphor video or a liquid crystal display capable of showing the user the image of the object 18 inspected.
  • Computer devices are provided that are able to control the system as a whole and the image acquisition process, and to support the software used to carry out classification of the materials, as well as any other algorithm needed to perform the specific application.
  • Figure 2 shows the spectra incident on the arrays of detectors 23, 24, 25 coinciding respectively with beams a, b, c, which have passed through an object 18 to be inspected with a thickness equivalent to 1 cm of iron.
  • the spectrum for beam a is shown with a dashed line, the spectrum for beam b with a solid line and the spectrum for beam c with a dotted line.
  • the primary polychromatic beam b is produced at the voltage of 140 kV
  • the crystal monochromator 10 is oriented so that it selects a diffracted monochromatic beam a with a mean energy of 120 kV
  • the crystal monochromator 11 is oriented so that it selects a diffracted monochromatic beam c with a mean energy of 70 keV.

Landscapes

  • Analysing Materials By The Use Of Radiation (AREA)
  • Apparatus For Radiation Diagnosis (AREA)
  • External Artificial Organs (AREA)
  • Optical Radar Systems And Details Thereof (AREA)
EP98120060A 1997-12-22 1998-10-23 Verfahren und Vorrichtung zur vielfach-Energie Abtastung Withdrawn EP0924967A3 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
ITMI972844 1997-12-22
ITMI972844 IT1297933B1 (it) 1997-12-22 1997-12-22 Dispositivo e metodo di scansione multienergia

Publications (2)

Publication Number Publication Date
EP0924967A2 true EP0924967A2 (de) 1999-06-23
EP0924967A3 EP0924967A3 (de) 2000-05-24

Family

ID=11378427

Family Applications (1)

Application Number Title Priority Date Filing Date
EP98120060A Withdrawn EP0924967A3 (de) 1997-12-22 1998-10-23 Verfahren und Vorrichtung zur vielfach-Energie Abtastung

Country Status (2)

Country Link
EP (1) EP0924967A3 (de)
IT (1) IT1297933B1 (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10127267A1 (de) * 2001-06-05 2002-12-19 Siemens Ag Bildgebendes medizinsches Röntgengerät
DE102005039642B3 (de) * 2005-08-22 2007-02-22 Yxlon International Security Gmbh Kollimatorensystem für eine Röntgendiffraktometrie, Röntgenbeugungsscanner sowie Verfahren zur Durchführung einer Röntgenbeugungsanalyse
US7187753B2 (en) 2003-02-06 2007-03-06 Siemens Aktiengesellschaft Monochromator for an X-ray radiator allowing modification of the X-ray spectral composition

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4365156A (en) * 1980-12-23 1982-12-21 Bell Telephone Laboratories, Incorporated Tunable θ-2θ device
EP0244766A2 (de) * 1986-05-06 1987-11-11 General Electric Company Bilderzeugung mittels zweier Energiespektren und kinestatischem Ladungsnachweis
US5164975A (en) * 1991-06-13 1992-11-17 The United States Of America As Represented By The United States Department Of Energy Multiple wavelength X-ray monochromators
GB2287164A (en) * 1994-03-03 1995-09-06 Heimann Systems Gmbh & Co Scanning luggage using x ray generators operating at different energies

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4365156A (en) * 1980-12-23 1982-12-21 Bell Telephone Laboratories, Incorporated Tunable θ-2θ device
EP0244766A2 (de) * 1986-05-06 1987-11-11 General Electric Company Bilderzeugung mittels zweier Energiespektren und kinestatischem Ladungsnachweis
US5164975A (en) * 1991-06-13 1992-11-17 The United States Of America As Represented By The United States Department Of Energy Multiple wavelength X-ray monochromators
GB2287164A (en) * 1994-03-03 1995-09-06 Heimann Systems Gmbh & Co Scanning luggage using x ray generators operating at different energies

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10127267A1 (de) * 2001-06-05 2002-12-19 Siemens Ag Bildgebendes medizinsches Röntgengerät
DE10127267B4 (de) * 2001-06-05 2008-01-03 Siemens Ag Bildgebendes medizinsches Röntgengerät
US7187753B2 (en) 2003-02-06 2007-03-06 Siemens Aktiengesellschaft Monochromator for an X-ray radiator allowing modification of the X-ray spectral composition
DE102005039642B3 (de) * 2005-08-22 2007-02-22 Yxlon International Security Gmbh Kollimatorensystem für eine Röntgendiffraktometrie, Röntgenbeugungsscanner sowie Verfahren zur Durchführung einer Röntgenbeugungsanalyse

Also Published As

Publication number Publication date
IT1297933B1 (it) 1999-12-20
EP0924967A3 (de) 2000-05-24
ITMI972844A1 (it) 1999-06-22

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