ISO 23699:2026

• Abstract:

  This document defines terms used for the electron backscatter diffraction (EBSD) technique. This document covers both general and specific concepts classified according to their hierarchy in a systematic order. This document is applicable to standardization documents relevant to EBSD practices. In addition, some definitions in this document are applicable to transmission Kikuchi diffraction (TKD).

• Status: Published
• Publication Date: 27-Sep-2026
• ICS: 01.040.71 - Chemical technology (Vocabularies)
• ICS: 71.040.50 - Physicochemical methods of analysis
• Technical Committee: ISO/TC 202/SC 1 - Terminology
• Drafting Committee: ISO/TC 202/SC 1 - Terminology
• Current Stage: 6060 - International Standard published
• Start Date: 28-Sep-2026
• Due Date: 19-Feb-2027
• Completion Date: 28-Sep-2026

Overview

ISO 23699:2026 from the International Organization for Standardization (ISO) is the vocabulary standard for microbeam analysis - electron backscatter diffraction (EBSD). It defines the terms used across EBSD practices and organizes both general and specific concepts in a clear, systematic hierarchy.

This standard is especially useful for laboratories, instrument manufacturers, researchers, and technical committees that need consistent EBSD terminology in documentation, training, software, and standardization work. It also supports interoperability in related work involving transmission Kikuchi diffraction (TKD), where some definitions are applicable.

EBSD is widely used in scanning electron microscopy (SEM) to study crystalline materials, making accurate terminology essential for reporting, comparison, and data interpretation.

Key Topics

ISO 23699:2026 covers terminology linked to the full EBSD workflow, including:

• Physical basis of EBSD

  • crystal, crystal plane, crystal direction
  • crystallographic orientation
  • dynamical diffraction, Kikuchi diffraction
  • misorientation, symmetry, zone axis

• Instrumentation and hardware

  • EBSD detector
  • forescatter detector (FSD)
  • phosphor screen
  • pixelated sensor

• Operation and data acquisition

  • background correction
  • binning
  • detector distance/specimen-to-screen distance
  • exposure time, frame averaging
  • indexing, indexing hit rate, misindexing, non-indexing
  • pattern centre, pattern quality, phase identification
  • step size and working distance

• Data display and analysis

  • EBSD map and EBSD map pixel
  • grain, grain boundary, coincident side lattice boundary
  • Euler angles, inverse pole figure (IPF)
  • kernel average misorientation (KAM), local average misorientation (LAM)
  • orientation distribution function (ODF)
  • spherical Kikuchi map (SKM)

The vocabulary also reflects practical analysis concepts such as EBSP, Hough transform, orientation noise, and grain boundary character distribution (GBCD), helping ensure precision in scientific and industrial communication.

Applications

ISO 23699:2026 provides practical value in many EBSD-related environments, including:

• Materials science and metallurgy

  • texture analysis
  • grain structure characterization
  • phase mapping and orientation studies

• Industrial quality control

  • analysis of crystalline materials in production settings
  • consistent reporting in microstructure evaluation

• Advanced research

  • aerospace, nuclear, automotive, and microelectronics applications
  • earth sciences and crystallographic studies

• Technical documentation

  • standard definitions for manuals, reports, software interfaces, and training materials

By standardizing EBSD vocabulary, the document supports clearer communication and more reliable comparison of results across organizations and technologies.

Related Standards

ISO 23699:2026 is connected to other ISO terminology and EBSD-related documents, including:

• ISO 24173:2024 - used as a source for several crystallographic definitions
• ISO 13067:2020 - referenced for EBSD orientation and data-analysis terminology
• ISO 23703:2022 - referenced for EBSD and TKD-related definitions

These related standards reinforce consistency across electron backscatter diffraction, microbeam analysis, and crystallographic data interpretation. For organizations working with EBSD standards, ISO 23699:2026 serves as a core vocabulary reference for accurate and harmonized technical language.

International
Standard
ISO 23699
First edition
Microbeam analysis — Electron
2026-09
backscatter diffraction —
Vocabulary
Analyse par microfaisceaux — Diffraction d'électrons
rétrodiffusés — Vocabulaire
Reference number
© ISO 2026
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
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ISO copyright office
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Published in Switzerland
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative References . 1
3 Terms and definitions . 1
4 Terms related to the physical basis of electron backscatter diffraction. 1
5 Terms related to EBSD instrumentation or hardware . 4
6 Terms related to operation or data acquisition . 5
7 Terms related to data display and analysis . 7
Bibliography .11
Index .12

iii
Foreword
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iv
Introduction
Electron backscatter diffraction (EBSD) measurement is routinely and widely used to produce local
orientation maps of a polished surface of bulk materials in scanning electron microscopy (SEM), via the
automated recording and analysis of Kikuchi diffraction patterns. EBSD is a modern technique used to
evaluate phase distribution, grain size distribution, orientation of individual grains, disorientation inside
grains and grain boundary characteristics of the crystalline materials. EBSD is applied across a wide variety
of fields, such as in metals processing, aerospace, nuclear, automotive and microelectronics industries, and
earth sciences.
This document provides definitions of terms as they are used in the field of electron backscatter diffraction
by the international scientific and engineering communities that employ the technique.

v
International Standard ISO 23699:2026(en)
Microbeam analysis — Electron backscatter diffraction —
Vocabulary
1 Scope
This document defines terms used for the electron backscatter diffraction (EBSD) technique. This document
covers both general and specific concepts classified according to their hierarchy in a systematic order.
This document is applicable to standardization documents relevant to EBSD practices. In addition, some
definitions in this document are applicable to transmission Kikuchi diffraction (TKD).
2 Normative References
There are no normative references in this document.
3 Terms and definitions
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
4 Terms related to the physical basis of electron backscatter diffraction
4.1
crystal
crystal structure
entity consisting of a regular, repeated arrangement of atoms in space
Note 1 to entry: It is usually described by a space group, a crystal system, unit cell parameters (including the lengths
and angles between the unit cell axes) and the positions of the atoms inside the unit cell
[SOURCE: ISO 24173:2024, 3.1, modified — the second half of the definition has been moved to "Note 1 to
entry", and all original "Note" clauses removed.]
4.2
crystal unit cell
cell which is repeated (infinitely) to build up the crystal (4.1)
Note 1 to entry: It is usually defined by three lengths, a, b, c, and three angles, α, β, γ. The lengths are usually given in
nanometres and the angles in degrees.
4.3
crystal plane
plane, usually denoted as (hkl) or (hkil), that represents the intersection of a plane with the a-, b-, and c-axes
of the unit cell at distances of 1/h, 1/k, 1/l, where h, k, and l are integers, i=-(h+k)
Note 1 to entry: The integers h, k, and l are usually referred to as Miller indices of a crystal plane.
[SOURCE: ISO 24173:2024, 3.2, modified — “or (hkil)” and “i=-(h+k)” are added, “representing” are replaced
with “that represents”, “the minimum mutual” are removed. ]

4.4
crystal direction
direction, usually denoted as [uvw] or [uvtw], that represents a vector direction in multiples of the basis
vectors describing the a, b, and c crystal axes, where u, v, and w are integers, t=-(u+v)
[SOURCE: ISO 24173:2024, 3.3, modified — “or [uvtw]” and “where u, v, and w are integers, t=-(u+v)” are
added, “representing” is replaced with “that represents”. ]
4.5
crystallographic orientation
alignment of the crystal coordinate system (for example, [100], [010], [001] for a cubic crystal) in relation to
the specimen coordinate system
Note 1 to entry: The specimen coordinate system can be denoted as X, Y, Z. When EBSD (4.9) is applied to the study of
rolled materials, it is often denoted as RD, TD, ND (RD = reference (or rolling) direction, TD = transverse direction and
ND = normal direction).
[SOURCE: ISO 24173:2024, 3.4]
4.6
Laue class
eleven geometric crystal classes containing centrosymmetric crystallographic types of point groups (4.7)
and their subgroups
4.7
point group
group of symmetry (4.19) operations which maps a point lattice onto itself
Note 1 to entry: In three dimensions, the symmetry (4.19) operations of these groups are restricted to 1, 2, 3, 4, 6 and
-1, -2, -3, -4, -6, m, respectively.
4.8
dynamical diffraction
theory of diffuse inelastic scattering in which the electron is treated as a wave field which is scattered
multiple times by interaction with the periodic potential of the atoms in the crystal (4.1)
Note 1 to entry: Models based on dynamical diffraction theory are used to simulate EBSPs (4.10).
4.9
electron backscatter diffraction
EBSD
diffraction process that arises between the backscattered electrons and the atomic planes of a highly tilted
crystalline specimen when illuminated by a stationary incident electron beam
[SOURCE: ISO 23703:2022, 3.4]
4.10
electron backscatter diffraction pattern
EBSP
Kikuchi-pattern-like electron diffraction pattern which is generated on a phosphor screen (5.3), photographic
film or direct electron detector by backscatter diffracted electrons in a SEM
Note 1 to entry: A specimen is generally tilted to 70 degrees to get better quality of the diffraction pattern.
[SOURCE: ISO 23703:2022, 3.5, modified— “EBSD pattern” has been changed to “EBSP” and “or direct
electron detector” are added.]
4.11
Hough transform
mathematical transformation of image processing techniques, which converts a line in an image to a point
Note 1 to entry: This allows automated detection of bands in an EBSP (4.10).

Note 2 to entry: In EBSD (4.9), a linear Hough transform is used to identify the position and orientation (4.15) of the
Kikuchi bands in each EBSP (4.10), which enables the EBSP (4.10) to be indexed. Each Kikuchi band is identified as a
bright spot in Hough space. The Hough transform is essentially a special case of the Radon transform. Generally, the
Hough transform is for binary images, and the Radon transform is for grey-level images.
[SOURCE: ISO 23703:2022, 3.9]
4.12
Kikuchi diffraction
simple elastic approximation for dynamical diffraction (4.8)
[1]
Note 1 to entry: Proposed in 1928 by Seishi Kikuchi .
4.13
microtexture
population of crystallographic orientations (4.15) whose individual components are linked to their spatial
[2]
location within the microstructure
4.14
misorientation
difference in the alignment of the coordinate systems of two crystals with the same crystal structure (4.1),
which can be expressed as an angle/axis pair
Note 1 to entry: Misorientation is the rotation required to bring one crystal (4.1) into coincidence with another. It can
be described by a rotation matrix, a set of Euler angles (7.7), an axis/angle pair or a Rodrigues vector. The axis/angle
pair is most common, but the smallest angle description is generally used.
Note 2 to entry: The EBSD (4.9) software calculates the crystal orientation of a particular point on the specimen
surface based on the EBSP (4.10) acquired at that point. The software can then calculate the misorientation between
any two chosen pairs or groups of orientations (4.15) of the same crystal phase acquisition points.
[SOURCE: ISO 24173:2024, 3.14, modified — “in the orientation of two crystallites, usually” has been changed
to “in the alignment of the coordinate systems of two crystals with the same crystal structure, which can
be”]
4.15
orientation
mathematical description of the angular relationship between the crystal axes of the analysis point and a
reference frame, usually the specimen axes
[SOURCE: ISO 13067:2020, 3.1.3]
4.16
pseudosymmetry
potential for an EBSP (4.10) to be indexed in several different ways due to internal similarities within the
EBSP (4.10)
Note 1 to entry: Pseudosymmetry is a problem with some crystal orientations (4.15), usually when a main zone axis
is in the centre of the pattern. Typical cases are a {0001} pole for a hexagonal structure and a <111> pole for a cubic
structure.
Note 2 to entry: Structures such as high-symmetry tetragonal crystals with an axial ratio, c/a, approximately equal to
1 are also likely to exhibit pseudosymmetry in EBSPs (4.10).
Note 3 to entry: Pseudosymmetry effects can usually be minimized by decreasing the specimen-to-screen distance, in
order to capture more Kikuchi bands, and by using more bands for indexing (6.7).
[SOURCE: ISO 13067:2020, 3.1.9, modified — “EBSD pattern” are changed to “EBSP” and “Note 3 to entry” is
added]
4.17
transmission Kikuchi diffraction
TKD
diffraction process that arises between the dynamically diffracted electrons and the bottom atomic planes
of an electron transparent crystalline specimen illuminated by a stationary incident electron beam which
[3]
usually uses high energy (25 keV to 30 keV) incident electrons
Note 1 to entry: Commonly used alternative terms for TKD are “t-EBSD”.
Note 2 to entry: On-axis TKD is a variant of TKD. It uses a modified EBSD detector (5.1) inserted below the electron
transparent sample. This sample-detector geometry is very similar to that used in a TEM.
4.18
EBSD spatial resolution
minimum distance between two grains (7.9) (separated by a sharp boundary) that can produce two distinctly
different EBSPs (4.10), which can be correctly indexed using a specific indexing (6.7) method
Note 1 to entry: The physical spatial resolution of EBSD (4.9) is not related to the indexing (6.7) of the EBSD patterns,
but rather to the volume of material that generates the EBSD pattern.
Note 2 to entry: The effective spatial resolution of EBSD (4.9) is typically finer than the physical spatial resolution. It
is determined by the ability of the analysis software to discriminate between overlapping patterns, which often occur
near the boundary between two neighbouring grains (7.9).
4.19
symmetry
property an object is said to have if it looks the same when rotated, translated or mirrored in a certain way
[SOURCE: ISO 24173:2024, 3.20]
4.20
zone axis
point in an EBSP (4.10) where the centres of several Kikuchi bands intersect
Note 1 to entry: It corresponds to a low-index crystal direction (4.4) in the EBSP (4.10).
[SOURCE: ISO 24173:2024, 3.21]
4.21
phase
physically homogeneous volume in a material having the same structure and chemical composition
[SOURCE: ISO 13067:2020, 3.2.8]
5 Terms related to EBSD instrumentation or hardware
5.1
EBSD detector
detector used to capture the electron backscatter pattern and convert it to an image visible on the display
device (computer screen) via a video-camera
Note 1 to entry: Commonly, a high-sensitivity charged-coupled device (CCD), or complementary metal-oxide-
semiconductors (CMOS) is used.
[SOURCE: ISO 24173:2024, 3. 5]
5.2
forescatter detector
FSD
electron detector which provides an analog signal from a sample in the EBSD (4.9) geometry whose intensity
contains both background and diffraction signal from a single location on the sample

5.3
phosphor screen
screen used to convert the electron signal to a visible light signa
...