SIST EN ISO 32543-2:2026

SLOVENSKI STANDARD
01-julij-2026
Neporušitveno preskušanje - Značilnosti goriščne površine v industrijskih
rentgenskih sistemih za neporušitveno preskušanje - 2. del: Metoda z robom z
merilniki tipa luknje (ISO 32543-2:2026)
Non-destructive testing - Characteristics of focal spots in industrial X-ray systems - Part
2: Edge method with hole type gauges (ISO 32543-2:2026)
Zerstörungsfreie Prüfung - Charakterisierung von Brennflecken in Industrie-
Röntgenanlagen - Teil 2: Radiographisches Lochkamera Verfahren (ISO 32543-2:2026)
Essais non destructifs - Caractéristiques des foyers émissifs des tubes radiogènes
industriels - Partie 2: Méthode par effet de bord avec jauges de type à trous (ISO 32543-
2:2026)
Ta slovenski standard je istoveten z: EN ISO 32543-2:2026
ICS:
19.100 Neporušitveno preskušanje Non-destructive testing
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 32543-2
EUROPEAN STANDARD
NORME EUROPÉENNE
January 2026
EUROPÄISCHE NORM
ICS 19.100 Supersedes EN 12543-4:1999
English Version
Non-destructive testing - Characteristics of focal spots in
industrial X-ray systems - Part 2: Edge method with hole
or disk type test objects (ISO 32543-2:2026)
Essais non destructifs - Caractéristiques des foyers Zerstörungsfreie Prüfung - Charakterisierung von
émissifs des tubes radiogènes industriels - Partie 2: Brennflecken in Industrie-Röntgenanlagen - Teil 2:
Méthode par effet de bord avec dispositifs d'essai de Kantenmethode mit Lochtestkörpern (ISO 32543-
type à trous ou à disques (ISO 32543-2:2026) 2:2026)
This European Standard was approved by CEN on 25 December 2025.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2026 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 32543-2:2026 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 32543-2:2026) has been prepared by Technical Committee ISO/TC 135 "Non-
destructive testing" in collaboration with Technical Committee CEN/TC 138 “Non-destructive testing”
the secretariat of which is held by AFNOR.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by July 2026, and conflicting national standards shall be
withdrawn at the latest by July 2026.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN 12543-4:1999.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO 32543-2:2026 has been approved by CEN as EN ISO 32543-2:2026 without any
modification.
International
Standard
ISO 32543-2
First edition
Non-destructive testing —
2026-01
Characteristics of focal spots in
industrial X-ray systems —
Part 2:
Edge method with hole or disk type
test objects
Essais non destructifs — Caractéristiques des foyers émissifs des
tubes radiogènes industriels —
Partie 2: Méthode par effet de bord avec dispositifs d’essai de type
à trous ou à disques
Reference number
ISO 32543-2:2026(en) © ISO 2026

ISO 32543-2:2026(en)
© 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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Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
ISO 32543-2:2026(en)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms. 3
5 Principle and detectors . 4
5.1 Principle .4
5.2 Detectors.4
5.2.1 General .4
5.2.2 Imaging plates for computed radiography .4
5.2.3 Digital detector arrays (DDA) .5
5.2.4 Exposure conditions and image processing .5
6 Test equipment . 5
6.1 General .5
6.2 Essential characteristics of test object or Image Quality Indicator (IQI) .5
6.2.1 Nanofocus tubes and microfocus tubes (spot size < 100 µm). .5
6.2.2 Minifocus, mesofocus and macrofocus tubes (spot size ≥ 100 µm) .7
6.2.3 Alignment and position of the test object in the beam.8
7 Loading factors . 10
8 Measurement procedure and determination of the focal spot size .10
8.1 Measurement procedure .10
8.2 Evaluation using a line profile .11
8.3 Automated evaluation using a validated software .14
9 Classification and result of focal spot size evaluation .15
10 Test report .15
Annex A (Informative) Values for the classification of X-ray tube focal spot sizes .16
Bibliography . 19

iii
ISO 32543-2:2026(en)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
has been established has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely
with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by ISO Technical Committee TC 135, Non-destructive testing, Subcommittee
SC 5, Radiographic testing, in collaboration with the European Committee for Standardization (CEN)
Technical Committee CEN/TC 138, Non-destructive testing, in accordance with the Agreement on technical
cooperation between ISO and CEN (Vienna Agreement).
A list of all parts in the ISO 32543 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

iv
ISO 32543-2:2026(en)
Introduction
To cover the large range of effective focal spot sizes, different methods are specified in ISO 32543 series.
In this document, the edge method is intended as a user method for measurement of the effective focal
spot sizes of nano-, micro-, mini- and macro- (standard) focus tubes. The edge method uses hole type test
objects and is intended for field and lab applications where users need to observe the effective focal spot on
a regular basis and other methods are non-practical.
In ISO 32543-1, the pin hole method permits the measurement of focal spot shape and focal spot
sizes ≥ 100 µm.
This document (ISO 32543-2) uses the edge method with hole or disk type test objects.
ISO 32543-3 covers the measurement of the effective focal spot size of mini- and microfocus X-ray tubes
from 5 µm to 300 µm.
Two further methods are in preparation as a part of the ISO 32543 series, concerning:
1)
— ISO 32543-4 line pair test objects for measuring the effective focal spot size of micro- and nanofocus
X-ray tubes with focal spot sizes ranging from 0,2 µm to 100 µm. This method is intended for use by
manufacturers and users.
2)
— ISO 32543-5 reconstruction of the spot shape from hole test object measurements. The results are
equivalent to the pin hole method down to 0,2 µm, if no phase contrast is observed.
In the overlapping ranges, the different methods give similar values based on the edge response
measurement, which allow using the dedicated method also in a limited way outside the above specified
ranges.
1) Under preparation. Stage at the time of publication: ISO/AWI 32543-4.
2) Under preparation. Stage at the time of publication: ISO/AWI 32543-5.

v
International Standard ISO 32543-2:2026(en)
Non-destructive testing — Characteristics of focal spots in
industrial X-ray systems —
Part 2:
Edge method with hole or disk type test objects
1 Scope
This document specifies a method for the measurement of effective focal spot dimensions > 0,2 µm of X-ray
systems by means of the edge method applied to digital images taken from hole type or disk type test
objects if no phase contrast is observed. The imaging quality and the resolution of X-ray images depends
highly on the characteristics of the effective focal spot, in particular its size and two-dimensional intensity
distribution as seen from the detector plane.
This document specifies procedures for determining the effective size (dimensions) of standard, mini and
micro focal spots of industrial X-ray tubes for users in applications where the pin hole method according
to ISO 32543-1 is not applicable. The method specified in this document is applicable for measurement and
long-term monitoring of focal spot sizes without a pin hole camera.
This document can be used by manufacturers, if special hole test objects manufactured with lower tolerances
according to 6.2.1 are applied (see Figure 1). For measurements of the effective focal spot size, the accuracy
of the method in this document is lower than the methods specified in ISO 32543-1 (pin hole method) and
ISO 32543-3 (microfocus tubes) if using ASTM hole plate IQIs (see ASTM E1025, ASTM E1742), due to its
manufacturing tolerance of ±10 %.
NOTE For characterization of commercial X-ray tube types (i.e. for advertising or trade), the nominal values of
Annex A are preferred.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 16371-1, Non-destructive testing — Industrial computed radiography with storage phosphor imaging plates
— Part 1: Classification of systems
ISO 19232-5, Non-destructive testing — Image quality of radiographs — Part 5: Determination of the image
unsharpness and basic spatial resolution value using duplex wire-type image quality indicators
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
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/

ISO 32543-2:2026(en)
3.1
actual focal spot
X-ray emitting area of the anode as viewed from a position perpendicular to the anode surface
Note 1 to entry: The actual focal spot is also called thermal focal spot in other literature.
[SOURCE: ISO 32543-1:2024, 3.1]
3.2
effective focal spot
X-rays emitting area of the anode as viewed from the image plane of the detector
Note 1 to entry: The effective focal spot is also called optical focal spot in other literature.
[SOURCE: ISO 32543-1:2024, 3.2]
3.3
effective focal spot size
d
measured focal spot size
Note 1 to entry: For measurement and determination, see Clause 6.
[SOURCE: ISO 32543-1:2024, 3.3, modified — deleted the part “in accordance with this document” and added
Note 1 to entry, added symbol “d”]
3.4
roundness
RONt
value of the largest positive local roundness deviation added to the absolute value of the largest negative
local roundness deviation from a reference circle according to the ISO 12181 series
3.5
edge unsharpness
u
edge
measured summarised values of the profile length
Note 1 to entry: u is measured between 50 % and 84 % on left and right side of a profile function over a hole or disk
edge
test object image in a digital radiograph, multiplied by 1,47. See Figure 5.
3.6
nominal focal spot size
SS
characteristic value for X-ray tubes having measured spot sizes within a defined range
Note 1 to entry: The nominal focal spot size is determined from Table A.1 or Table A.2 based on the measured focal
spot, d (3.3).
[SOURCE: ISO 32543-1:2024, 3.4, modified — Note 1 to entry added]
3.7
focal spot class
FS
number used to classify X-ray tubes based on the nominal focal spot size (3.6)
Note 1 to entry: The ranges of focal spot sizes are defined in Table A.1 and Table A.2.
[SOURCE: ISO 32543-1:2024, 3.5, modified — Note 1 to entry added.]

ISO 32543-2:2026(en)
3.8
signal-to-noise ratio
SNR
ratio of mean grey value to the standard deviation of the grey values (noise) measured in a region of interest
Note 1 to entry: Grey values are numeric values of pixels, which are directly proportional to the detector exposure
dose and having a value of zero, if the detector was not exposed.
Note 2 to entry: After detector correction, a grey value of zero is obtained, if the detector is not exposed.
3.9
contrast-to-noise ratio
CNR
ratio of the difference of the mean grey values between two image areas to the averaged standard deviation
of the grey values
3.10
pixel coverage of a focal spot
N
number of pixels in an image by which it is blurred by the focal spot size in x- or y-direction
Note 1 to entry: N corresponds to the number of pixels across the spot edge profile.
Note 2 to entry: x- or y-direction for example width or length.
3.11
interpolated basic spatial resolution value
detector
iSR
b
smallest geometrical detail, which can be resolved in a digital image at magnification
equal to one and corresponds to half of the measured interpolated detector unsharpness in a digital image
Note 1 to entry: The measurement of interpolated unsharpness is specified in ISO 19232-5 and ASTM E2002. See also
ASTM E1000 and ASTM E2736.
3.12
anticipated focal spot size
d
ap
size of a focal spot as provided by a manufacturer, a specification or obtained by an older measurement
4 Symbols and abbreviated terms
For the purposes of this document, the symbols and abbreviated terms given in Table 1 apply.
Table 1 — Symbols and abbreviated terms
Symbol or abbreviated Definition
term
CNR contrast-to-noise ratio
DDA digital detector array
diameter of the hole or disk in a test object
D
HD
d effective focal spot size
d anticipated focal spot size
ap
FS focal spot class
IP imaging plate
IQI image quality indicator
detector
iSR the interpolated basic spatial resolution of the detector in µm, measured with the proce-
b
dure of ISO 19232-5 or ASTM E 2002

ISO 32543-2:2026(en)
TTabablele 1 1 ((ccoonnttiinnueuedd))
Symbol or abbreviated Definition
term
M magnification of the test object
M required minimum magnification of the test object
min
M magnification of the focal spot and the edge unsharpness
spot
M optimum magnification
opt
m source-object distance
N pixel coverage of a focal spot, number of pixels across the spot edge profile
n object-detector distance
P pixel size of an image corrected by the magnification of the test object
image
P pixel size of the detector
detector
RONt roundness as defined in ISO 12181-1
SNR signal-to-noise ratio
SS nominal focal spot size
t thickness of a shim of copper, brass, or Inconel
t thickness of a plate hole Image Quality Indicator (IQI)
u edge unsharpness as measured by the 2 × (50 % – 84 %) method
edge
iu interpolated inherent unsharpness of the detector
detector
5 Principle and detectors
5.1 Principle
The method is based on indirect measurement of the focal spot size calculated from the geometric
unsharpness of the radiographs of hole or disk test objects. For this purpose, hole or disk test objects with
sharp edges are imaged either on an imaging plate (IP) by computed radiography, or by means of a digital
detector array (DDA) using a suitable geometric magnification (see below for magnification requirements).
The edge unsharpness of the hole or disk structures is evaluated.
The hole method of ASTM E1165-20, Annex A, and its specified test objects are considered for this document
for measurement of spot sizes ≥ 0,1 mm. Other test objects are specified to cover the range of spot sizes <
0,1 mm.
5.2 Detectors
5.2.1 General
The shape of focal spots is important for manufacturers and evaluation of possible changes in the X-ray tube
with operating time.
5.2.2 Imaging plates for computed radiography
The following equipment is required for the measurement, if using computed radiography:
a) a test object according to 6.2;
b) a computed radiography system, consisting of imaging plates and a scanner, configured such that the
pixel size is appropriate for the measurement (Clause 6). The image shall be of a sufficient size to image
magnified test objects and the region around the test object to obtain a profile as shown in Figure 5b.
The computed radiography system shall meet the requirements of ISO 16371-1 class IP 1 and imaging plates
shall be packed in low absorbing cassettes using no metal screens.

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