Backscattering X-Ray Material Identification for Security Screening
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Solution Overview
Problem
Existing devices for identifying materials in objects, such as luggage, face challenges in distinguishing between explosives and everyday materials due to similar density characteristics, especially when substances are buried or in liquid form, and struggle to differentiate water from explosives.
Innovation Solution
The method involves using a collimated X-Ray photon source and spectrometric detector to measure backscattered X-Ray photons at different depths, calculating a combined attenuation coefficient and a scattering parameter to determine the material's density and atomic number, allowing for precise identification of materials regardless of their position or form.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If charge integration mode is used to detect X-Ray photons, then the total energy and mean attenuation can be measured, but the atomic number information is lost and false alarms increase
Solution Approach 1:
The patent segments the detection process by using multiple detectors with different energy thresholds instead of a single integrated detector. This allows separation of the measurement into multiple independent channels, each capturing specific energy ranges, thereby preserving both attenuation and atomic number information simultaneously.
Solution Approach 2:
The patent introduces a new dimension to the detection space by measuring X-Ray photon energies across multiple thresholds rather than integrating total charge. This transforms the single-dimensional integrated signal into a multi-dimensional energy spectrum, enabling simultaneous extraction of both attenuation and atomic number characteristics.
2Adaptability or versatility
If conventional transmission X-Ray devices are used, then material identification is possible, but they cannot inspect voluminous objects or packages left against walls
Solution Approach 1:
The patent inverts the conventional transmission geometry by using backscattering detection. Instead of placing detectors on the opposite side of the object from the X-Ray source, the detectors are positioned on the same side to capture scattered photons. This inversion enables inspection of objects regardless of their position or orientation.
Solution Approach 2:
The backscattering detection system provides universal inspection capability that works for various object types and positions. The same device can inspect voluminous objects, packages against walls, and other configurations without requiring position adjustment, making it multi-functional and highly adaptable.
3Ease of operation
If backscattering technology is used, then access to one side of the object is sufficient, but distinguishing between materials with similar densities remains difficult
Solution Approach 1:
The patent segments the detection signal into multiple energy thresholds, allowing analysis of the energy distribution pattern rather than relying solely on total intensity. This segmentation enables differentiation between materials with similar densities by examining their distinct scattering energy signatures.
Solution Approach 2:
The patent changes the measurement parameter from total integrated intensity to energy-distributed photon counts across multiple thresholds. This parameter transformation reveals additional material characteristics through the energy spectrum, enabling precise differentiation between materials with similar density values.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables reliable identification of illicit substances and differentiation between water and explosives, improving security by providing accurate material composition analysis without the need for additional information beyond mean attenuation.
Implementation Method 1
In this case, the source of X-Ray photons and the detector are located on the same side of the object. The X-Ray photons are going to bounce off the object more than pass through it. This technique becomes a good inspection tool for the detection and the identification of explosives, which are materials in which the atoms constituting them have low atomic numbers, for example less than 10. Indeed, they are constituted of carbon, oxygen, hydrogen, nitrogen. In this case, the phenomenon of Compton effect scattering is preponderant compared to the phenomenon of absorption by photoelectric effect at the energies conventionally used
Implementation Method 2
the phenomenon of Compton effect scattering is preponderant compared to the phenomenon of absorption by photoelectric effect at the energies conventionally used
Data Source
AI summary
The invention relates to a device for identifying a material of an object having a source of X-Ray photons and a spectrometric detector, the source irradiating the object with an incident beam and the detector measuring a magnitude of a backscattered beam from the incident beam after scattering in a volume (δV) of the material and an energy of the X-Ray photons of the backscattered beam. The incident and backscattered beams forming a scattering angle (θ). An adjusting device adjusts the position between the source, the detector and the object in order for the volume to be at different depths with a constant angle. A processing device processes the two magnitudes in two positions and the energy in one position and calculates an attenuation coefficient (μmaterial (E0, E1, ε)). An estimating device estimates the density (ρ) of the material.