Method and apparatus for determining a material of a detected item
First Claim
1. A method for determining a material of a detected item in an object comprising:
- irradiating the material with a primary X-ray beam;
measuring a diffraction spectrum of the material, with the spectrum comprising X-rays of the primary beam diffracted from the material;
measuring an X-ray absorption of the material and an average atomic number of the material by measuring X-rays of the primary beam transmitted through the material;
determining the average atomic number of the material from the measured absorption;
comparing the measured diffraction spectrum and determined average atomic number of the material to known diffraction spectra and known average atomic numbers of known materials.
0 Assignments
0 Petitions
Accused Products
Abstract
A method for determining the material of a detected item in objects, especially explosives in luggage, using X-ray diffraction. In this method, wherein scatter radiation deflected at the crystal source of the material is measured and compared to characteristic energy spectra or diffraction spectra of the various explosives, the absorption by the material influences the X-ray diffraction spectrum, so that information is missing, and inaccurate conclusions may be drawn regarding the material. To improve this method, the primary beam of an X-ray source is used for measuring the absorption. The beam passes through the material, and, from the absorption, an average atomic number of the material is determined, and this information additionally is used in the comparison to known diffraction spectra. For this purpose, a collimation/detector arrangement preferably has only one collimator (8) and one detector (9), with the collimator (8) having a conically-expanding circular slot (1), which simulates a predetermined angle of the beam path, and a central blind bore (1) opening toward the X-ray source. First and second detectors (13, 14) are disposed in the bore to detect lower and higher X-ray energy, respectively.
-
Citations
8 Claims
-
1. A method for determining a material of a detected item in an object comprising:
-
irradiating the material with a primary X-ray beam;
measuring a diffraction spectrum of the material, with the spectrum comprising X-rays of the primary beam diffracted from the material;
measuring an X-ray absorption of the material and an average atomic number of the material by measuring X-rays of the primary beam transmitted through the material;
determining the average atomic number of the material from the measured absorption;
comparing the measured diffraction spectrum and determined average atomic number of the material to known diffraction spectra and known average atomic numbers of known materials. - View Dependent Claims (2, 3, 4, 5)
-
-
6. An apparatus for determining a material of a detected item in an object comprising a diffraction apparatus and a computer connected thereto, and wherein
said diffraction apparatus comprises an X-ray source for producing a primary X-ray beam and a collimator/detector arrangement positioned to receive the primary X-ray beam after passing through an object and including a detector a collimator; -
said detector comprises an X-ray detector positioned downstream of the collimator and having an X-ray sensitive surface oriented toward the collimator;
said collimator has a central, blind-bore closed at the end facing the detector and at least one conically expanding circular slot that simulates a predetermined angle and is oriented toward said X-ray sensitive surface of the detector; and
first and second spaced detection devices mounted within the blind bore and connected to the computer, with said first and second detection devices detect relatively lower and relatively higher energy X-rays, respectively, and being spaced in the central opening such that the second detection device located behind the first detection device. - View Dependent Claims (7, 8)
-
Specification