An x-ray scanning system includes an x-ray source that produces a collimated fan beam of incident x-ray radiation. The system also includes a chopper wheel that can be irradiated by the collimated fan beam. The chopper wheel is oriented with a wheel plane containing the chopper wheel substantially non-perpendicular relative to a beam plane containing the collimated fan beam. In various embodiments, a disk chopper wheel's effective thickness is increased, allowing x-ray scanning with end point energies of hundreds of keV using relatively thinner, lighter, and less costly chopper wheel disks. Backscatter detectors can be mounted to an exterior surface of a vehicle housing the x-ray source, and slits in the disk chopper wheel can be tapered for more uniform target irradiation.

In some embodiments, a method for processing inspection data associated with cargo irradiated by a plurality N of pulses of inspection is provided. The method includes obtaining the inspection data, the inspection data being representative of intensity values of pixels of an inspection image of the including data associated with a higher energy mode, and data associated with a lower energy mode; generating a histogram having, as a first axis, bins corresponding to pixel intensity values HM associated with the higher energy mode and, as a second axis, bins corresponding to pixel intensity values LM associated with the lower energy mode; selecting a bin corresponding to a most frequent bin of the pixel intensity values HM; and generating a transformation table by mapping each bin of the pixel intensity values LM with the selected bin of the pixel intensity values HM.

In an example, there is disclosed a method for determining a material in a cargo, the cargo including a first object made of a first material and a second object made of a second material. The method includes obtaining image data associated with an inspection image of the cargo, for at least two levels of radiation energy, obtaining equivalence data associated with mass equivalence of at least one of the first material and the second material with respect to a reference material, for the at least two levels of radiation energy, obtaining observation data based on the image data and the equivalence data, and determining at least one of the first material and the second material, based on the obtained observation data.

Methods for quantitatively separating x-ray images of a subject having three or more component materials into component images using spectral imaging or multiple-energy imaging with 2D radiographic hardware implemented with scatter removal methods. The multiple-energy system may be extended by implementing DRC multiple energy decomposition and K-edge subtraction imaging methods.

There is presented an apparatus for identifying a sample. Such an apparatus may be used to detect unwanted items as part of a security screening system. The apparatus includes a platform for receiving the sample, at least one electromagnetic radiation emitter, a plurality of detectors and a calculator. The electromagnetic radiation emitter is adapted to provide a plurality of conical shells of radiation. Each conical shell has a characteristic propagation axis associated with it. The detectors are arranged to detect radiation diffracted by the sample upon incidence of one or more conical shells of radiation. Each detector is located on the characteristic propagation axis associated with a corresponding conical shell. The calculator is adapted to calculate a parameter of the sample based on the detected diffracted radiation. The parameter includes a lattice spacing of the sample.

The specification discloses methods of adjusting calibration data in an X-ray inspection system. Calibration data is initially generated. X-ray scan images of a cargo container are then acquired. Each of the X-ray scan images are segmented into regions of interest, where the regions of interest volumetrically encompass a known material or a material corresponding to a known HS code. Using the calibration data, first data indicative of Zeff of each of the regions of interest are determined. The first data is compared with second data indicative of known Zeff corresponding to the known materials and/or HS codes. The calibration data is then adjusted to generate a second calibration data if the first and second data differ significantly. The calibration data is replaced by the second calibration data in the memory.

An x-ray scanning system, and corresponding method, includes an x-ray source that produces incident x-ray radiation having end-point x-ray energy, which, in various embodiments, can be greater than about 200 keV, between about 200 keV and about 500 keV, or greater than about 500 keV. The system also includes a disk chopper wheel that can be irradiated by and attenuate the incident x-ray radiation. The disk chopper wheel further defines one or more slits configured to pass the incident x-ray radiation through the disk chopper wheel for scanning a target. In some embodiments, the high end-point x-ray energies with disk chopper wheels are facilitated by forming the incident x-ray radiation as a collimated fan beam and/or orienting the chopper wheel with a wheel plane substantially non-perpendicular to a fan beam plane, increasing effective thickness of a disk chopper wheel to attenuate incident x-rays of higher energies.

The present specification discloses a high speed scanning system for scanning cargo carried by rail. The system uses of a two-dimensional X-ray sensor array with, in one embodiment, a cone-beam X-ray geometry. The pulse rate of X-ray source is modulated based on the speed of the moving cargo to allow a distance travelled by the cargo between X-ray pulses to be equal to the width of the detector, for a single energy source, and to half the width of the detector for a dual energy source. This ensures precise timing between the X-ray exposure and the speed of the passing object, and thus accurate scanning of cargo even at high speeds.

An x-ray scanning system includes an x-ray source that produces a collimated fan beam of incident x-ray radiation. The system also includes a chopper wheel that can be irradiated by the collimated fan beam. The chopper wheel is oriented with a wheel plane containing the chopper wheel substantially non-perpendicular relative to a beam plane containing the collimated fan beam. In various embodiments, a disk chopper wheel's effective thickness is increased, allowing x-ray scanning with end point energies of hundreds of keV using relatively thinner, lighter, and less costly chopper wheel disks. Backscatter detectors can be mounted to an exterior surface of a vehicle housing the x-ray source, and slits in the disk chopper wheel can be tapered for more uniform target irradiation.

A variable mode X-ray transmission system is provided that can be operated in low or high dose rate modes depending upon the area or portion of the vehicle to be screened. In one embodiment, variable dose rate is achieved by use of a novel collimator. The systems disclosed in this application enable the scanning of a vehicle cab portion (occupied by people, such as a driver) at low dose rate, which is safe for human beings, while allowing the scanning of the cargo portion (unoccupied by people) at a high dose rate. Rapid switching from low dose rate to high dose rate operating mode is provided, while striking a balance between high material penetration for cargo portion and low intensity exposure that is safe for occupants in the cab portion of the inspected vehicle.