121 results about "Grating interferometer" patented technology

An x-ray CT system for x-ray phase contrast and / or x-ray dark field imaging has a grating interferometer that has a first grating structure that has a number of band-shaped x-ray emission maxima and minima arranged in parallel, the maxima and minima exhibiting a first grating period, a second band-shaped grating structure that produces, as a phase grating, a partial phase offset of x-ray radiation passing therethrough and that exhibits a second grating period, a third band-shaped grating structure with a third grating period with which relative phase shifts of adjacent x-rays and / or their scatter components are detected, and a device for value-based determination of the phase between adjacent x-rays and / or for value-based determination of the spatial intensity curve per detector element perpendicular to the bands of the grating structures. The third grating structure has a grating period that is larger by a factor of 2 to 5 than the grating period of the first grating structure.

Embodiments of methods and apparatus are disclosed for obtaining a phase-contrast digital radiographic imaging system and methods for same that can include an x-ray source for radiographic imaging; a beam shaping assembly including a collimator and a source grating, an x-ray grating interferometer including a phase grating, and an analyzer grating; and an x-ray detector, where a single arrangement of the beam shaping assembly, the x-ray grating interferometer and a position of the detector is configured to provide spectral information (e.g. at least two images obtained at different relative beam energies).

The present invention is directed to a heterodyne reflectometer system and method for obtaining highly accurate phase shift information from heterodyned optical signals, from which extremely accurate film depths can be calculated. A linearly polarized light comprised of two linearly polarized components that are orthogonal to each other, with split optical frequencies, is directed toward a film causing one of the optical polarization components to lag behind the other due to an increase in the optical path in the film for that component. A pair of detectors receives the beam reflected from the film layer and produces a measurement signal, and the beam prior to incidence on the film layer and generates a reference signal, respectively. The measurement signal and reference signal are analyzed by a phase detector for phase shift. The detected phase shift is then fed into a thickness calculator for film thickness results. A grating interferometer may be included with the heterodyne reflectometer system with a grating, which diffracts the reflected beam into zeroth- and first-order bands, which are then detected by separate detectors. A detector receives the zeroth-order beam and generates another measurement signal. Another detector receives the first-order beam and generates a grating signal. The measurement signal from the grating and reference signal may be analyzed by a phase detector for phase shift, which is related to the thickness of the film. Conversely, either measurement signal may be analyzed with the grating signal by a phase detector for detecting a grating phase shift. The refractive index for the film may be calculated from grating phase shift and the heterodyne phase shift. The updated refractive index is then used for calculating thickness.

A two-DOF (degree of freedom) heterodyne grating interferometer displacement measurement system comprises a two-frequency laser, a grating interferometer, a measuring grating, a receiver, and an electronic signal processing part. The grating interferometer comprises a polarizing beam splitter, a reference grating and a refraction element. The measurement system measures displacement according to optical grating diffraction, optical Doppler Effect and optical beat frequency principle. A two-frequency laser beam emitted by the two-frequency laser enter the grating interferometer and the measuring grating before two light signals are output to the receiver, and the signals are sent to the electronic signal processing part. When the grating interferometer is in two-DOF linear relative motion with the measuring grating, the system can output two linear displacements. The measurement system allows for sub-nano or higher resolution and precision, and can measure two linear displacements simultaneously. The measurement system has the advantages of insensitivity to environment, high measurement precision, small size, light weight and the like, and after the measurement system is used as a lithography machine ultra-precision workpiece bench position measurement system, comprehensive performances of a workpiece bench can be improved.