MyScope
training for advanced research

Glossary

Edit…

Absorption
X-ray absorption is most commonly due to the photo-electric effect. An X-ray photon is absorbed by an atom and a photo-electron is emitted.
Accuracy
The "truth" of the analysis
Atom probe tomography (APT)
Atom probe tomography: a materials analysis technique for 3D imaging and measurement of chemical composition at the atomic scale.
Atomic number (Z)
The number of protons in the nucleus of an atom.
Auger electron spectroscopy (AES)
Auger electron spectroscopy: a technique used to determine the elemental composition of the surface layers of a sample from analysis of Auger electrons.
Background
The contribution of Bremsstrahlung X-rays to the X-ray counts under a Characteristic X-ray peak.
Bremsstrahlung X-rays
Braking radiation. X-rays produced by slowing down of the primary-beam electrons by the electric field around atomic nuclei in the sample.
Characteristic X-rays
X-rays with discrete energies reflecting the electronic configuration of the parent atom, produced after ionization of an inner electron shell and subsequent relaxation of the excited atom.
Chemical bonding
The strong force of attraction that holds atoms together in a molecule or crystal.
Continuum
The energy distribution of the Bremsstrahlung X-rays, which decreases with increasing energy.
Critical ionization energy
The energy required to remove an electron from a stable shell or subshell.
Crystal defect
An imperfection in the crystal structure, or arrangement of atoms, in a crystalline substance.
Crystal structure
The regular arrangement of atoms, ions or molecules that make up a crystalline substance.
Dead time
Dead time is when the system is processing the previous signal and not processing new data.
Detection limit
The lowest amount of an analyte in a sample that can be detected but not necessarily quantified
Duane-Hunt limit
The maximum energy of an energy dispersive spectrum. It is equal to the energy of the electrons in the primary electron beam.
Dwell time
The time spent collecting X-rays from each pixel in an X-ray element map. Usually milliseconds to a second.
Electron diffraction (ED)
Electron diffraction: a technique for identifying the structure of a sample by examining the diffraction patterns produced by scattering of an electron beam by the sample in a TEM.
Electron energy loss spectroscopy (EELS)
Electron energy loss spectroscopy. The analysis of electrons that have passed through a thin foil specimen. EELS provides a wealth of information about the sample, including electronic structure of specimen atoms, valence states, thickness and more.
Electron microprobe analysis (EMPA)
Electron microprobe analysis = Electron probe microanalysis. Quantitative microanalysis based on WDS.
Electron probe microanalysis (EPMA)
Electron probe microanalysis = Electron microprobe analysis. Quantitative microanalysis based on WDS.
Electron shells
Stable energy levels of electrons in the cloud surrounding the atomic nucleus.
Energy dispersive spectroscopy (EDS)
Energy dispersive spectroscopy/spectrum. A technique for determining elemental composition from Characteristic X-rays in an energy spectrum.
Energy dispersive x-ray (EDX)
Energy dispersive X-ray microanalysis. A technique for determining elemental composition from Characteristic X-rays in an energy spectrum.
Escape peak
A spectral artifact resulting when a Si Ka X-ray is generated from the detector crystal reducing the measured energy of an incoming X-ray photon by 1.74 keV - the energy of the Si Ka X-ray.
Fluorescence
The production of a second generation X-rays by the X-rays produced by the primary-beam electrons. Also known as secondary fluorescence.
Fluorescence yield
The relative yield of Characteristic X-rays to Auger electrons produced by an atom following inner shell ionization.
Fourier transform infrared spectroscopy (FTIR)
Fourier transform infrared spectroscopy: a technique that provides information about the chemical bonding and molecular structure of the sample.
Full width half maximum (FWHM)
The width of a peak at half the maximum height. For energy dispersive spectra, the peak height is corrected for Bremsstrahlung X-rays. The FWHM is measured in eV.
In situ
In place.
Inductively coupled plasma - mass spectrometry (ICP-M)
Inductively coupled plasma - mass spectrometry: a wet sample technique in which a solution is introduced to an argon plasma to produce ions which are analysed by mass spectrometer.
Inductively coupled plasma - optical emission spectrometry (ICP-O)
Inductively coupled plasma - optical emission spectrometry: a wet sample technique in which a solution is introduced to an argon plasma at 8000?C. The elements emit light of characteristic wavelengths which is analysed by a spectrometer.
Inner shell ionization
Removal of an electron from an inner (K, L or M) electron shell. The atom is in an excited state.
Instrumental neutron activation analysis (INAA)
Instrumental neutron activation analysis
Intensity
The number of X-ray counts recorded at any energy within an energy dispersive spectrum. The intensity may be given as counts or count rate in cps.
Ion
An atom, or group of atoms, that has lost one or more electrons making it positively charged (a cation) or gained one or more electrons making it negatively charged (an anion).
Ionization energy
The energy required to remove an electron from a stable shell or subshell.
Isotopes
Atoms of the same element that have the same number of protons in the nucleus but different numbers of neutrons.
K ratio
The ratio of the (background corrected) intensity for an element of interest in the sample to the (background corrected) intensity of the element in a standard.
Laser
A device that emits light (infrared, visible and ultra-violet) through optical amplification. The light is highly coherent and monochromatic.
Laser ablation - inductively coupled plasma - mass spectrometry (LA-IC)
Laser ablation - inductively coupled plasma - mass spectrometry: a technique for measuring isotopes and trace element compositions in a sample. A laser is used to ablate material from the sample, which is transported to an inductively couples argon plasma. The plasma generates ions that are then analysed by mass spectrometer.
Lithium-drifted silicon detector (Si(Li)
Si semiconductor crystal in which recombination sites for electron-hole pairs are filled with Li, creating intrinsic Si in which the electrons and holes can be separated.
Major element
> 10 wt%
Mass Absorption Coefficients (MAC)
A matrix of numbers reflecting the absorption of a particular X-ray line (the emitter) by all the other elements in the periodic table.
Matrix corrections
Corrections applied to the measured raw intensities of X-ray peaks to allow for differences in composition between the sample and the standards.
Micro-particle-induced X-ray emission (m-PIX)
An in situ microbeam technique based on particle induced X-ray emission.
Micro-X-ray diffraction (m-XRD)
An in situ microbeam technique based on X-ray diffraction spectroscopy.
Micro-X-ray fluorescence (m-XRF)
An in situ microbeam technique based on X-ray fluorescence spectroscopy.
Minor element
1-10 wt%
nanoSIMS
An instrument for imaging and measuring isotopes and trace elements in a sample at high spatial resolution (50 nm).
Nanotechnology
The development and use of devices whose size is on the atomic or molecular scale.
Overvoltage ratio
The ratio of the energy of the electrons in the primary beam to the critical ionization energy for a particular Characteristic X-ray line. U = Eo/Ec.
Particle induced X-ray emission (PIXE)
Particle induced X-ray emission: the sample is bombarded with a beam of particles (He ++ ions), with emission of Characteristic X-rays, but little or no Bremsstrahlung X-rays.
Photo-electric effect
An X-ray photon is absorbed by an atom in the sample and an electron, a photo-electron, is emitted.
Photo-electron
An electron emitted from an atom in the sample following absorption of an X-ray photon.
Precision
The reproducibility of the analysis based on statistics related to the number of counts in the X-ray spectrum.
Process time
The length of time spent reducing noise from the signal coming from the X-ray detector.
Proton
A stable elementary particle that occurs in the nuclei of all atoms. The proton has a positive charge equal in magnitude to that of the electron.
Pulse pile-up correction
The process of removing spectral artifacts from the energy dispersive spectrum and returning the counts to the channels where they should have been recorded.
Qualitative analysis
Identification of the elements present in a sample, but their abundances.
Quantitative analysis
Calculation of the abundances of the elements present in a sample.
Raman spectroscopy
Raman spectroscopy: a technique for measuring the chemical structure of a sample by measuring molecular vibrations (Raman scattering) induced by a laser.
Random errors
Statistical fluctuations, in either direction, due to limitations of the measurement device.
Redox state
A measure of the control of electrons that an atom has in a compound compared with an atom of the pure element.
Region of interest
A defined energy range in the energy dispersive spectrum, usually corresponding to the energy of a Characteristic X-ray peak for mapping.
Relaxation
Recovery of the atom to a stable state following ionization, by emission of a Characteristic X-ray or an Auger electron.
Resolution - spatial
In microanalysis, the size of the smallest particle that can be analysed.
Resolution - spectral
In microanalysis, the width of a characteristic X-ray peak measured in either energy (eV) or wavelength (nm), at half the maximum peak height.
Secondary ion mass spectrometry (SIMS)
Secondary ion mass spectrometry: a technique for measuring isotopes and trace element compositions of a sample. A primary ion beam ablates the sample to produce a beam of secondary ions. The secondary ions are analysed by a mass spectrometer.
Siegbahn notation
The most commonly used convention for naming Characteristic X-ray lines based on the shell of the element that is ionized and the relative intensity of the Characteristic X-ray that is produced.
Silicon drift detector (SDD)
X-ray detector composed of concentric rings of p-doped Si implanted on a single crystal of n-Si. A high voltage is applied from inside to outside the detector to collect the electrons generated by incoming X-rays.
Standard reference material
A material whose composition is well known through multiple analytical techniques or round-robin testing. X-ray counts from the sample are compared with those from the standard.
Standardized quantitative analysis
Spectra from samples are compared with spectra from standards collected on the same instrument and at the same analytical conditions.
Standardless quantitative analysis
Spectra from samples are compared with default spectra stored with the quantification software package
Sum peak
A spectral artifact resulting when the pulse processor cannot discriminate two X-rays that arrive almost simultaneously and records one X-ray with energy equal to the sum of the two contributing X-rays.
Systematic errors
Reproducible inaccuracies in the same direction, probably caused by an error in the experimental setup.
Time constant
The time allowed for the pulse processor to evaluate the incoming charge pulse.
Time-of-flight secondary ion mass spectroscopy (TOF-S)
Time-of-flight SIMS: a technique for surface analysis that focusses a beam of primary ions on the sample and measures secondary ions sputtered from the surface to provide information about molecular and elemental species.
Top-hat filter
Mathematical filter applied to each channel in the energy dispersive spectrum to remove noise and slope of the continuum.
Trace element
<1 wt%
Wavelength dispersive spectroscopy (WDS)
Wavelength dispersive spectroscopy/spectrum. A technique for determining elemental composition from the wavelengths and intensities of Characteristic X-rays.
X-ray diffraction (XRD)
X-ray diffraction: a technique for identifying materials and characterizing their crystal structure by measuring the intensities of X-rays diffracted by the sample.
X-ray energy dispersive spectroscopy (XEDS)
Energy dispersive X-ray microanalysis. A technique for determining elemental composition from Characteristic X-rays in an energy spectrum.
X-ray fluorescence (XRF)
X-ray fluorescence: an analytical technique that uses X-rays to generate Characteristic X-rays from a sample, and measure the energy and intensity of the resulting X-ray peaks to identify and quantify the elements present in the sample.
X-ray photoelectron spectroscopy (XPS)
X-ray photoelectron spectroscopy: a surface analysis technique that provides chemical state information on the elements detected. The sample is irradiated with X-rays causing emission of photo-electrons whose energies are characteristic of the elements in the irradiated volume.
X-rays
X-rays are electromagnetic radiation with wavelengths in the range 0.01 to 10 nm.
ZAF corrections
Matrix corrections based on differences in atomic number (Z), absorption (A) and fluorescence (F) between the sample and standards.