Question 1

Absolute quantification

Accepted Answer

Use of an analytical technique to determine the absolute number of atoms per area, as opposed to a relative or percent composition.

Question 2

Accompanying edges

Accepted Answer

Minor, less intense edges that follow a major edge.

Question 3

Argon gas

Accepted Answer

Argon (Ar) is widely used as the process gas during ion milling for transmission electron microscope (TEM) specimen preparation. It is also an important carrier gas during plasma cleaning to remove carbon (C) contamination from TEM samples.

Question 4

Beam current

Accepted Answer

Number of electrons in the transmission electron microscope's (TEM) electron beam and is usually measured in pA or nA.

Question 5

Bragg angle

Accepted Answer

The angle between an incident beam and a set of planes in the crystal where scattering shows the maximum intensity due to constructive interference.

Question 6

Bright field / dark field (BF/DF)

Accepted Answer

An imaging technique where only the unscattered electrons (bright field) or the scattered electrons (dark field) are collected to form an image. The term also refers to a bright field (BF)/dark field (DF) scanning transmission electron microscope (STEM) detector mechanism that allows you to insert the DF and BF detectors one at the time.

Question 7

Charge-coupled device (CCD)

Accepted Answer

An imaging device where the charge is moved to an area within the same device where it can be digitized.

Question 8

Chemical state

Accepted Answer

The chemical or electronic state of a particular element in a sample. This can change depending on the element’s bonding or local coordination.

Question 9

Collection angle

Accepted Answer

The angle that electrons are collected in the electron energy loss spectrometer.

Question 10

Convergence angle

Accepted Answer

The angle that the probe forms on the specimen.

Question 11

Core loss

Accepted Answer

The region of the electron energy loss spectrum with signatures coming from the ionization edges.

Question 12

Crossover

Accepted Answer

The point in between two lenses at that the electrons from different paths converge.

Question 13

Current drift

Accepted Answer

Slow (10 – 100 s) changes in electron current.

Question 14

Delayed edge

Accepted Answer

When the maximum intensity is far from the edge onset.

Question 15

Diffraction contrast

Accepted Answer

Features in imaging caused by variations of intensity of diffraction across the image.

Question 16

Drift tube voltage

Accepted Answer

In DigitalMicrograph^® software from Gatan, a control that applies a precise voltage to temporarily accelerate the beam as it passes through the prism, and thereby results in a net downward deflection of the dispersed beam. See also Spectrum offset and Energy shift.

Question 17

DualEELS

Accepted Answer

The (nearly) simultaneous acquisition of two different energy regions of the electron energy loss spectrum under the same experimental conditions. For more information see DualEELS™.

Question 18

Dynamic range

Accepted Answer

The intensity range that a particular device can handle.

Question 19

Edge threshold energy

Accepted Answer

The difference in energy between a core level initial state and the lowest unoccupied energy state in an excited atom.

Question 20

Elastic scattering

Accepted Answer

Scattering event that results in no loss of energy.

Question 21

Electron energy loss spectroscopy (EELS)

Accepted Answer

A method of measuring the loss of energy in electrons as they travel through a specimen.

Question 22

Electron gun

Accepted Answer

A component that generates a beam of electrons in vacuum.

Question 23

Electron microscope

Accepted Answer

A microscope that uses accelerated electrons to illuminate a specimen.

Question 24

Electron scattering

Accepted Answer

Deviation of the original electron path as result of the interaction with matter.

Question 25

Electron transparent

Accepted Answer

A specimen that is thin enough that electrons can travel through it.

Question 26

Emission current

Accepted Answer

Measurement of the number of electrons emitted by a filament (electron gun).

Question 27

Energy dispersive x-ray spectroscopy (EDS)

Accepted Answer

An analytical technique used for analysis and characterization of a sample; also referred to as EDX, XEDS, etc.

Question 28

Energy drift

Accepted Answer

Slow (10 – 100 s) energy fluctuations in the electron beam due to some instrumental instabilities.

Question 29

Energy filter

Accepted Answer

A device capable of imaging electrons that have lost a selected range of energy.

Question 30

Energy loss

Accepted Answer

The transfer of energy by the incoming electron to the sample as a result of the interaction with the matter.

Question 31

Energy loss near edge structure (ELNES)

Accepted Answer

The region of the energy loss spectrum that represents transitions from core level states to empty states just above the Fermi level. ELNES gives hints about the band structure (density of unoccupied states). For more information see ELNES.

Question 32

Energy loss near edge structure (ELNES)

Accepted Answer

The region of the energy loss spectrum that represents transitions from core level states to empty states just above the Fermi level. ELNES gives hints about the band structure (density of unoccupied states). For more information see ELNES.

Question 33

Energy-filtered transmission electron microscopy (EFTEM)

Accepted Answer

An analytical technique used in transmission electron microscopy, by which electrons of particular energies are used to form a diffraction pattern or image. For more information, please see EFTEM.

Question 34

Energy-filtering transmission electron microscope spectrum imaging (EFTEM SI)

Accepted Answer

The use of energy-filtered transmission electron microscope images to form a data cube containing two spatial dimensions (images) and a third energy dimension (spectra). For more information, please see EFTEM, Spectrum Imaging, and EFTEM SI.

Question 35

Excited atom

Accepted Answer

An atom that has absorbed energy and is now at a higher energy level.

Question 36

Field emission gun (FEG)

Accepted Answer

An electron source where the electrons are generated by the application of a strong electric field. The electrons tunnel, quantum mechanically, through the remaining energy barrier into the vacuum.

Question 37

Filament

Accepted Answer

The heated source of electrons in a themionic electron emitter.

Question 38

Fluorescent screen

Accepted Answer

A screen coated on one side by a material that emits light when exposed to electrons. Used for viewing electron images, diffracting patterns, or spectra.

Question 39

Flyback time

Accepted Answer

Time needed to ensure that the beam goes to the selected spot at the end of each sweep.

Question 40

Focal length of lens

Accepted Answer

The measurement of how a lens converges or diverges the electrons.

Question 41

Forward scattering

Accepted Answer

When scattering occurs mainly along the same direction as the incoming beam.

Question 42

Fourier transform (FT)/Fast Fourier transform (FFT)

Accepted Answer

An algorithm that converts a signal from its original domain (commonly spatial or time) into a frequency domain.

Question 43

Fourier-log deconvolution

Accepted Answer

Mathematical process used to remove the effects of plural scattering in the electron energy loss spectrum. It requires presence of the low-loss portion with the zero-loss peak (ZLP) in the same spectrum.

Question 44

Fourier-ratio deconvolution

Accepted Answer

Mathematical process used to remove the effects of plural scattering in the electron energy loss spectrum. It requires presence of the low-loss portion with the zero-loss peak (ZLP) but not necessarily in the same spectrum.

Question 45

Frame time

Accepted Answer

Time used for the acquisition of each frame of spectrum or image.

Question 46

Gatan imaging filter (GIF)

Accepted Answer

An imaging filter designed and manufactured by Gatan. For more information please visit the GIF Quantum® energy filters page on www.gatan.com.

Question 47

Gaussian peak

Accepted Answer

Peak that has the symmetric shape of the Gaussian function.

Question 48

Goniometer

Accepted Answer

Allows the specimen to be traversed and tilted.

Question 49

Ground state

Accepted Answer

Electron configuration of an atom at the lowest possible energy.

Question 50

High resolution imaging

Accepted Answer

Allows direct imaging of the atomic structure.

Question 51

High vacuum

Accepted Answer

Pressure ranging from 10^-6 – 10^-9 Pa.

Question 52

High-loss region

Accepted Answer

Region of the electron energy loss spectrum with signatures coming from the ionization edges.

Question 53

Holey grid

Accepted Answer

A TEM sample support where a coarse support mesh (typically Cu) supports a fine film (typically C) with the presence of much smaller circular or square holes.

Question 54

Hydrogenic edge shape

Accepted Answer

Edges with a sharp onset that resemble the ionization from a single hydrogen atom.

Question 55

Inelastic scattering

Accepted Answer

When there is a loss of energy accompanying the scattering event.

Question 56

Intermediate lens

Accepted Answer

Lenses that are used to magnify the image from the objective lens. Typically these are not the final stage of magnification.

Question 57

Jump-ratio imaging

Accepted Answer

The process used for energy-filtering transmission electron microscopy (EFTEM) mapping where one filtered image before the edge of interest and one filtered image after the edge of interest are collected. The ratio of the images forms the jump-ratio image.

Question 58

Lens

Accepted Answer

Magnetic fields in the TEM that are used to control the beam, and form and magnify images.

Question 59

Low angle scattering

Accepted Answer

Scattering that occurs at relatively low angle compared to the characteristic scattering angle for the material.

Question 60

Low-loss signal

Accepted Answer

Analysis of the electron energy loss spectrum at low energy, generally including the zero-loss peak (ZLP).

Question 61

Magnetic lens

Accepted Answer

Lenses that are used to focus and deflect charged particles such as electrons in the case of transmission electron microscopy (TEM).

Question 62

Major edge

Accepted Answer

A strong edge that represents the main signature for a particular element in the electron energy loss spectrum.

Question 63

Monochromatic

Accepted Answer

A beam of electrons with a range of energies that are narrower than the original electron source.

Question 64

Multiple linear least square fitting (MLLS)

Accepted Answer

A technique used to separate overlapping edges. For more information please see Advanced.

Absolute quantification

Accompanying edges

Argon gas

Beam current

Bragg angle

Bright field / dark field (BF/DF)

Charge-coupled device (CCD)

Chemical state

Collection angle

Convergence angle

Core loss

Crossover

Current drift

Delayed edge

Diffraction contrast

Drift tube voltage

DualEELS

Dynamic range

Edge threshold energy

Elastic scattering

Electron energy loss spectroscopy (EELS)

Electron gun

Electron microscope

Electron scattering

Electron transparent

Emission current

Energy dispersive x-ray spectroscopy (EDS)

Energy drift

Energy filter

Energy loss

Energy loss near edge structure (ELNES)

Energy loss near edge structure (ELNES)

Energy-filtered transmission electron microscopy (EFTEM)

Energy-filtering transmission electron microscope spectrum imaging (EFTEM SI)

Excited atom

Field emission gun (FEG)

Filament

Fluorescent screen

Flyback time

Focal length of lens

Forward scattering

Fourier transform (FT)/Fast Fourier transform (FFT)

Fourier-log deconvolution

Fourier-ratio deconvolution

Frame time

Gatan imaging filter (GIF)

Gaussian peak

Goniometer

Ground state

High resolution imaging

High vacuum

High-loss region

Holey grid

Hydrogenic edge shape

Inelastic scattering

Intermediate lens

Jump-ratio imaging

Lens

Low angle scattering

Low-loss signal

Magnetic lens

Major edge

Monochromatic

Multiple linear least square fitting (MLLS)

Non-linear least squares (NLLS)

Objective aperture

Objective aperture

Phase contrast

Pixel

Plasmon energy

Plasmon loss

Plasmon loss

Pole piece gap

Precipitates

Projector lens

Refraction

Refractive index

Ronchigram

Scan space

Scanning