Method and apparatus for determining both density and atomic number of a material composition using Compton scattering
OwnerYoung S. Ham, Chester F. Poranskiinventors
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Abstract
An x-ray backscatter tomography system includes a collimated x-ray source for directing a collimated beam towards a target at a select position and orientation, a first detector array for measuring photons scattered at a selected first angle, and a second detector array for measuring photons scattered at a selected second angle different from the first angle. The system is also responsive to the first and second detectors for calculating the density and atomic number of the target.
Claims18
A method for determining both density and atomic number of a material of an object using Compton scattering, said method simultaneously employing at least two detector/collimators for detecting photons having been Compton scattered, said first detector/collimator collecting photons scattered through angle .theta..sub.1, and said second detector/collimator collecting photons scattered through .theta..sub.2, said method further employing a means for obtaining two expressions associated with said first and second detector/collimators wherein said expressions are solved to determine both the density and atomic number of the material of an object.
A method for determining the material composition of the material of an object by using Compton scattering comprising:
- (a) simultaneously employing first and second detector/collimators to collect photons scattered through angles .theta..sub.1 and .theta..sub.2,
- (b) obtaining two expressions associated with said first and second detector/collimators and reducing said two expressions to two equations having two unknowns, .rho..sub.e and .mu..sub.a (E.sub.0),
- (c) determining the density and atomic number of said material of said object.
An apparatus for determining both density and atomic number of the material of an object using Compton scattering, said apparatus comprising a first detector/collimator and a second detector/collimator, said first detector/collimator collecting photons scattered through angle .theta..sub.1, and said second detector/collimator collecting photons scattered through .theta..sub.2, said apparatus further comprising a means for obtaining two expressions associated with said first and second detector/collimators wherein said expressions are solved to determine both the density and atomic number of the material of an object.
An apparatus for determining the material composition of the material of an object using Compton scattering comprising:
- (a) first and second detector/collimators for collecting photons scattered through angles .theta..sub.1 and .theta..sub.2,
- (b) means for obtaining two expressions associated with said first and second detector/collimators and reducing said two expressions associated with said first and second detector/collimators to two equations having two unknowns, .rho..sub.e and .mu..sub.a (E.sub.0),
- (c) means for determining the density and atomic number of the material of said object.
A method for determining the material composition of the material of an object by using Compton scattering comprising:
- (a) providing a radiation source;
- (b) providing first and second detector/collimators;
- (c) positioning said radiation source at a location exterior to one side of said object, and irradiating said object at a point P with a beam of incident photons travelling a length l.sub.0, along a ray path .alpha. between point P and the surface of said object, having intensity l.sub.0, and energy E.sub.0 ;
- (d) simultaneously employing said first detector/collimators and said second detector/collimators wherein said first detector/collimators collects photons scattered through an angle .theta..sub.1, having an intensity I.sub.1, and an energy E.sub.1, and travelling a length l.sub.1, along ray path .beta..sub.1, between said point P and the surface of said object along said ray path .beta..sub.1, and wherein said second detector/collimators collects photons scattered through an angle .theta..sub.2, having an intensity I.sub.2, and an energy E.sub.2, and travelling a length l.sub.2 ;
- along ray path .beta..sub.2, between said point P and the surface of said object along said ray path .beta..sub.2 ;
- (e) obtaining two expressions associated with said first and second detector/collimators and reducing said two expressions to two equations having two unknowns, .rho..sub.e and .mu..sub.a (E.sub.0);
- (f) determining the density and atomic number of said material of said object.
An apparatus for determining the material composition of the material of an object by using Compton scattering comprising:
- a radiation source positioned at a location exterior to one side of said object to irradiate said object;
- a first detector/collimators for detecting photons having been Compton scattered through an angle .theta..sub.1, at a known first detector/collimators position located exterior to one side of said object;
- a second detector/collimators for detecting photons having been Compton scattered through an angle .theta..sub.2 at a known, second detector/collimators position, different from said first detector/collimators position, located exterior to one side of said object;
- means for obtaining two expressions associated with said first and second detector/collimators and reducing said two expressions associated with said first and second detector/collimators to two equations having two unknowns, .rho..sub.e and .mu..sub.a (E.sub.0);
- means for determining the density and atomic number of the material of said object.
Dependencies are inferred from the claim text.