All articles starting with X
1,563 articles
X-ray interferometry
X-ray interferometry is the measurement of interference between X-ray beams, used to determine phase shifts in matter and, in split-and-delay form, to produce pairs of coherent femtosecond X-ray pulses.
X-ray linear dichroism
X-ray linear dichroism (XLD) is the difference in a material's x-ray absorption between two orthogonal linear polarizations, arising from anisotropic unoccupied electronic states; its magnetic variant probes antiferromagnetic order.
X-ray linear dichroism microscopy
X-ray linear dichroism microscopy is a synchrotron imaging technique whose contrast reveals the orientation of chemical bonds, orbitals, and magnetic axes, first demonstrated by Ade and Hsiao in 1993.
X-ray lithography
X-ray lithography (XRL), also known as proximity X-ray lithography, is a microfabrication technique that patterns features of 100 nm or smaller by exposing photoresist through a mask with X-rays.
X-ray luminescence computed tomography
X-ray luminescence computed tomography (XLCT) is a hybrid imaging method, reported by Guillem Pratx and colleagues in 2010, that maps x-ray-excited luminescent nanoparticles inside an object from surface optical measurements.
X-ray magnetic circular dichroism
X-ray magnetic circular dichroism (XMCD) measures the difference in absorption of left- and right-circularly polarized X-rays by a magnetized sample, giving element-specific spin and orbital magnetic moments.
X-ray magnetic laminography
X-ray magnetic laminography is a three-dimensional X-ray imaging method that reconstructs magnetization in extended flat samples by rotating them about a tilted axis with XMCD contrast.
X-ray microscopy
X-ray microscopy is an imaging technique that uses X-rays to visualize the structure and composition of materials at scales from tens of nanometers to tens of micrometers.
X-ray microtomography
X-ray microtomography, or micro-CT, is a nondestructive imaging method that reconstructs high-resolution 3D images of an object's internal structure from many X-ray projections, typically resolving 10–50 µm.
X-ray nanotomography
X-ray nanotomography, or nano-CT, is a non-destructive imaging method that maps a sample's internal structure in 3D with 400 nm precision or better, bridging micro-CT and electron microscopy.
X-ray nova
An X-ray nova, also called a soft X-ray transient, appears suddenly in a binary system, peaks within days, and fades over months as gas surges toward a neutron star or black hole.
X-ray parametric down-conversion
X-ray parametric down-conversion (XPDC) is a nonlinear process in which an X-ray pump photon splits into two lower-energy photons in a crystal such as diamond.
X-ray phase contrast
X-ray phase contrast is a set of X-ray imaging techniques that form contrast from phase shifts rather than absorption, revealing soft tissues and low-density materials at comparable or lower dose.
X-ray phase-contrast imaging
X-ray phase-contrast imaging is an imaging technique that forms images from the phase shifts X-rays acquire through an object rather than absorption alone, used to visualize weakly absorbing soft tissue.
X-ray phase-contrast tomography
X-ray phase-contrast tomography, or phase-contrast computed tomography, is an imaging method that reconstructs 3D maps of the X-ray refractive index, revealing soft-tissue contrast conventional CT cannot.
X-ray photoelectron spectroscopy
X-ray photoelectron spectroscopy, also called electron spectroscopy for chemical analysis, is a technique that measures electrons emitted by X-rays to identify the elements, bonding, and oxidation states in a material's outermost few nanometers.
X-ray photoemission electron microscopy
X-ray photoemission electron microscopy (XPEEM) is a full-field, surface-sensitive technique that images electrons emitted by X-rays, mapping chemical states and magnetic domains down to tens of nanometers.
X-ray photon correlation spectroscopy
X-ray photon correlation spectroscopy (XPCS) is a synchrotron scattering technique that measures nanoscale dynamics, from diffusion to flow, by tracking how a coherent X-ray speckle pattern fluctuates over time.
X-ray powder diffraction
X-ray powder diffraction (XRD) is an analytical technique that directs an X-ray beam at a finely ground crystalline sample, using the diffraction pattern to identify phases and quantify mixtures.
X-ray ptychography
X-ray ptychography is a lensless scanning imaging method that reconstructs quantitative nanoscale images from overlapping X-ray diffraction patterns, using algorithms to recover lost phase information.
X-ray quasi-periodic eruptions
X-ray quasi-periodic eruptions are recurring soft X-ray bursts from galactic nuclei, first seen in 2018 in galaxy GSN 069 and linked to objects colliding with black hole accretion disks.
X-ray reconstruction of moving morphology
X-ray reconstruction of moving morphology (XROMM) is a biomechanics technique, introduced by Elizabeth Brainerd in 2010, that animates CT bone models against biplanar X-ray video.
X-ray reflectivity
X-ray reflectivity (XRR), also called X-ray reflectometry, is a surface-sensitive analytical technique measuring reflected X-rays at grazing angles to determine film thickness, density, and roughness.
X-ray reflectometry
X-ray reflectometry (XRR), also called specular XRR, is a nondestructive technique that measures reflected X-ray intensity versus angle to determine thin-film thickness, density, and interface roughness.
X-ray reverberation mapping
X-ray reverberation mapping is an astronomical timing technique that measures light-travel delays between direct X-rays from a black hole's corona and their reflections off the accretion disk.
X-ray scattering
X-ray scattering is a family of techniques that analyzes X-rays scattered by a material to determine its structure, morphology, and electronic excitations, underpinning much of materials science and condensed matter physics.
X-ray spectrometry
X-ray spectrometry is a family of analytical techniques that measures X-ray interactions with matter to determine a sample's elemental composition and electronic structure, nondestructively covering most elements from parts-per-million levels to 100%.
X-ray spectroscopy
X-ray spectroscopy is a family of analytical techniques that uses X-rays to determine elemental composition, electronic structure, and local atomic environment, including XAS, XRF, and XPS.
X-Ray Spex
X-Ray Spex were an English punk rock band formed in London in 1976 and fronted by Poly Styrene, distinguished by prominent saxophone and lyrics satirizing consumer culture.
X-ray transform
The X-ray transform is an integral transform that maps a function on Rn to its integrals over straight lines, and it models CT, PET, and seismic tomography.