This disclosure relates to an apparatus and methods for applying X-ray reflectometry (XRR) in characterizing three dimensional nanostructures supported on a flat substrate with a miniscule sampling area and a thickness in nanometers. In particular, this disclosure is targeted for addressing the difficulties encountered when XRR is applied to samples with intricate nanostructures along all three directions, e.g. arrays of nanostructured poles or shafts. Convergent X-ray with long wavelength, greater than that from a copper anode of 0.154 nm and less than twice of the characteristic dimensions along the film thickness direction, is preferably used with appropriate collimations on both incident and detection arms to enable the XRR for measurements of samples with limited sample area and scattering volumes.

An X-ray imaging system (XI) configured for phase contrast and/or dark-field imaging The system comprises an X-ray source (XS) operable to cause X-radiation to emanate from a focal spot (SF) of the source (XS) and an X-ray sensitive detector (D) operable to SMF detect the X-radiation after interaction of said X-radiation with an object to be imaged, if present, between the X-ray source and the detector (D). A control logic (CL) is operable to cause the X-ray imaging apparatus to operate in any one of two modes, an object image acquisition mode and a scattering measurement mode. When in scattering measurement mode, the X-radiation receivable at the detector comprises a higher proportion of scattering radiation than in X-radiation receivable when the system is in object image acquisition mode.

Various aspects include methods compensating for Compton scattering effects in pixel radiation detectors. Various aspects may include determining whether gamma ray detection events occurred in two or more detector pixels within an event frame, determining whether the gamma ray detection events occurred in detector pixels within a threshold distance of each other in response to determining that gamma ray detection events occurred in two or more detector pixels within the event frame, and recording the two or more gamma ray detection events as a single gamma ray detection event having an energy equal to the sum of measured energies of the two or more gamma ray detection events located in a detector pixel having a highest measured energy in response to determining that the gamma ray detection events occurred in detector pixels within the threshold distance of each other.

Scatter correction for tomography: for each position, two images are acquired, a first image without and a second image with a scatter reducing aperture plate (50). A scatter image is calculated by subtracting the second image from the first image. The apertures (48) in the scatter reducing plate (50) are arranged hexagonally in order to optimise the packaging density of the apertures.

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.

Molecular structure of a crystal may be solved based on at least two diffraction tilt series acquired from a sample. The two diffraction tilt series include multiple diffraction patterns of at least one crystal of the sample acquired at different electron doses. In some examples, the two diffraction tilt series are acquired at different magnifications.

Crystallographic information of crystalline sample can be determined from one or more three-dimensional diffraction pattern datasets generated based on diffraction patterns collected from multiple crystals. The crystals for diffraction pattern acquisition may be selected based on a sample image. At a location of each selected crystal, multiple diffraction patterns of the crystal are acquired at different angles of incidence by tilting the electron beam, wherein the sample is not rotated while the electron beam is directed at the selected crystal.

A method and system for imaging an object are described herein. A scatter image of the object is generated at a projection angle. In generating the scatter image, a non-grid image of the object is acquired using a radiation source and a detector. An aperture plate is positioned between the object and the detector and a first grid image of the object is acquired. The aperture plate includes a plurality of apertures positioned on a grid. The aperture plate is moved to a second position and a second grid image of the object is acquired. A scatter image of the object is generated based on the non-grid image, the first grid image, and the second grid image and stored.

An apparatus for generating corrected X-ray projection data from target X-ray projection data obtained by performing an X-ray scan with a detector having an anti-scatter grid, and a method for creating a lookup table and generating corrected X-ray projection data. The apparatus includes a detector configured to detect incident X-rays, an anti-scatter grid configured to suppress scattered radiation incident on the detector, and an X-ray source configured to irradiate the target with X-rays. Processing circuitry is configured to cause the X-ray source to scan, using a peak kilovoltage (kVp), the target to produce the target projection data, determine a patient-to-detector distance (PDD) and an area irradiated (FS), transform the target projection data into a spatial frequency domain, determine scatter values by accessing the lookup table using the kVp, PDD, and FS values, and subtract the scatter values from the frequency components to obtain the corrected X-ray projection data.

A method of analysis of X-ray spectra in an instrument fits a measured sample spectrum using a combination of at least one measured reference spectrum with at least one calculated function. The method includes measuring a reference spectrum as a plurality of measured values for a plurality of energy bins from at least one reference sample; selecting a region or multiple regions of interest corresponding to a plurality of the energy bins and, for each region of interest, recording the profile for the respective plurality of energy bins from the measured reference spectrum. The method further comprises measuring a sample spectrum as a plurality of intensity values for a plurality of energy bins; and fitting the measured sample spectrum to a fit function, the fit funtion including the at least one profile in at least one respective region of interest of the measured spectrum as well as the at least one calculated function.