Non-destructive testing - Characteristics of focal spots in industrial X-ray systems for use in non-destructive testing - Part 2: Pinhole camera radiographic method

This document specifies a method for the measurement of effective focal spot dimensions above 0,1 mm of X-ray systems up to and including 1000 kV tube voltage by means of the pinhole camera method with digital evaluation. The tube voltage applied for this measurement is restricted to 200 kV for visual film evaluation.
The imaging quality and the resolution of X-ray images depend highly on the characteristics of the effective focal spot, in particular the size and the two dimensional intensity distribution as seen from the detector plane.
This test method provides instructions for determining the effective size (dimensions) of standard (macro focal spots) and mini focal spots of industrial X-ray tubes. This determination is based on the measurement of an image of a focal spot that has been radiographically recorded with a "pinhole" technique and evaluated with a digital method.
For the characterization of commercial X-ray tube types (i.e. for advertising or trade) it is advised that the specific FS values of Annex A are used.

Zerstörungsfreie Prüfung - Charakterisierung von Brennflecken in Industrie-Röntgenanlagen für die zerstörungsfreie Prüfung - Teil 2: Radiographisches Lochkamera-Verfahren

Dieses Dokument legt ein Verfahren für die Messung von effektiven Brennfleckgrößen oberhalb von 0,1 mm für Röntgenanlagen bis einschließlich 1 000 kV Röntgenröhrenspannung mit dem Lochkamera-Verfahren mit digitaler Auswertung fest. Die für die Messung angewendete Röntgenröhrenspannung ist für eine visuelle Auswertung des Films auf 200 kV beschränkt.
Die Bildgüte und die Auflösung von Röntgenbildern hängen in hohem Maße von den Eigenschaften des effektiven Brennflecks ab, insbesondere von der Größe und der zweidimensionalen Intensitätsverteilung, wie von der Detektorebene aus gesehen.
Dieses Prüfverfahren gibt Anleitungen für die Bestimmung der effektiven Größe (Abmessungen) von Standard-Brennflecken (Makro-Brennflecken) und Mini-Brennflecken industrieller Röntgenröhren an. Diese Bestimmung basiert auf der Messung eines Bildes eines Brennflecks, das mithilfe von Röntgenstrahlung und einer "Lochkamera"-Technik aufgenommen und mit einem digitalen Verfahren ausgewertet wurde.
Für die Charakterisierung handelsüblicher Röntgenröhren-Arten (d. h. zu Werbe- oder Handelszwecken), wird empfohlen, dass die spezifischen FS Werte von Anhang A hierfür verwendet werden.

Essais non destructifs - Caractéristiques des foyers émissifs des tubes radiogènes industriels utilisés dans les essais non destructifs - Partie 2 : Méthode radiographique par sténopé

Le présent document spécifie une méthode de détermination des dimensions des foyers émissifs effectifs supérieures à 0,1 mm des tubes radiogènes dont la tension est inférieure ou égale à 1 000 kV, au moyen de la méthode radiographique par sténopé avec examen numérique. La tension appliquée pour ce mesurage est limitée 200 kV pour l’examen visuel du film.
La qualité d’image et la résolution des images radiographiques dépendent étroitement des caractéristiques du foyer émissif effectif, en particulier de ses dimensions et de la répartition bidimensionnelle de l’intensité observée depuis le plan du détecteur.
Cette méthode d’essai fournit des instructions pour déterminer la taille effective (les dimensions) des foyers standards (microfoyers émissifs) et des minifoyers des tubes radiogènes industriels. Cette détermination repose sur le mesurage d’une image d’un foyer émissif qui a été enregistrée radiographiquement à l’aide d’une technique par sténopé et examinée au moyen d’une méthode numérique.
Pour la caractérisation des tubes radiogènes de type commercial (c’est-à-dire pour publicité ou commerce), il est recommandé d’utiliser les valeurs FS spécifiques indiquées à l’Annexe A.

Neporušitvene preiskave - Značilnosti goriščne površine v industrijskih rentgenskih sistemih za neporušitveno preskušanje - 2. del: Metoda s kamero z luknjico

General Information

Status
Published
Public Enquiry End Date
16-Jun-2019
Publication Date
09-May-2021
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
21-Apr-2021
Due Date
26-Jun-2021
Completion Date
10-May-2021

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SLOVENSKI STANDARD
SIST EN 12543-2:2021
01-junij-2021
Nadomešča:
SIST EN 12543-2:2009
Neporušitvene preiskave - Značilnosti goriščne površine v industrijskih
rentgenskih sistemih za neporušitveno preskušanje - 2. del: Metoda s kamero z
luknjico

Non-destructive testing - Characteristics of focal spots in industrial X-ray systems for use

in non-destructive testing - Part 2: Pinhole camera radiographic method
Zerstörungsfreie Prüfung - Charakterisierung von Brennflecken in Industrie-
Röntgenanlagen für die zerstörungsfreie Prüfung - Teil 2: Radiographisches
Lochkamera-Verfahren

Essais non destructifs - Caractéristiques des foyers émissifs des tubes radiogènes

industriels utilisés dans les essais non destructifs - Partie 2 : Méthode radiographique

par sténopé
Ta slovenski standard je istoveten z: EN 12543-2:2021
ICS:
19.100 Neporušitveno preskušanje Non-destructive testing
SIST EN 12543-2:2021 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST EN 12543-2:2021
---------------------- Page: 2 ----------------------
SIST EN 12543-2:2021
EN 12543-2
EUROPEAN STANDARD
NORME EUROPÉENNE
April 2021
EUROPÄISCHE NORM
ICS 19.100 Supersedes EN 12543-2:2008
English Version
Non-destructive testing - Characteristics of focal spots in
industrial X-ray systems for use in non-destructive testing
- Part 2: Pinhole camera radiographic method

Essais non destructifs - Caractéristiques des foyers Zerstörungsfreie Prüfung - Charakterisierung von

émissifs des tubes radiogènes industriels utilisés dans Brennflecken in Industrie-Röntgenanlagen für die

les essais non destructifs - Partie 2 : Méthode zerstörungsfreie Prüfung - Teil 2: Radiographisches

radiographique par sténopé Lochkamera-Verfahren
This European Standard was approved by CEN on 1 March 2021.

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, Turkey 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

© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 12543-2:2021 E

worldwide for CEN national Members.
---------------------- Page: 3 ----------------------
SIST EN 12543-2:2021
EN 12543-2:2021 (E)
Contents Page

European foreword ...................................................................................................................................................... 3

Introduction .................................................................................................................................................................... 4

1 Scope .................................................................................................................................................................... 5

2 Normative references .................................................................................................................................... 5

3 Terms and definitions ................................................................................................................................... 5

4 Test equipment ................................................................................................................................................ 6

4.1 Essential characteristics of the pinhole .................................................................................................. 6

4.2 Alignment and position of the pinhole camera .................................................................................... 7

4.3 Position of the radiographic image detector ........................................................................................ 8

4.4 Requirements on the radiographic image detector ........................................................................... 9

4.5 Image processing equipment for digital images................................................................................ 10

4.6 Loading factors .............................................................................................................................................. 10

5 Measurement and determination of the focal spot size .................................................................. 10

5.1 Measurement procedure ............................................................................................................................ 10

5.2 Measurement with digital technique (preferred method) ............................................................ 12

5.3 Evaluation with digital technique using Integrated Line Profiles (ILP) ................................... 12

5.4 Measurement of effective focal spot size visually using film radiographs ............................... 15

6 Classification and result of focal spot size measurement .............................................................. 15

Annex A (normative) Values for the classification of X-ray tube focal spot sizes ............................... 17

Bibliography ................................................................................................................................................................. 19

---------------------- Page: 4 ----------------------
SIST EN 12543-2:2021
EN 12543-2:2021 (E)
European foreword

This document (EN 12543-2:2021) has been prepared by 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 October 2021, and conflicting national standards shall

be withdrawn at the latest by October 2021.

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 12543-2:2008.
The main changes compared to the previous edition are as follows:
— The document has been technically and editorially revised;
— The scope of application was extended up to 1000 kV for digital detectors;
— Table 1 has been extended to include pin holes of 10 micron diameter;

— In Annex A, Focal Spot Classes have been introduced for simple X-ray tube classification;

— Chapter 5 introduces a new measurement procedure “Integrated Line Profile”;

— Table A.1 and Table A2 provide a new classification and result of focal spot measurement.

According to the CEN-CENELEC Internal Regulations, the national standards organisations 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, Turkey and the

United Kingdom.
---------------------- Page: 5 ----------------------
SIST EN 12543-2:2021
EN 12543-2:2021 (E)
Introduction

In order to cover the large range of effective focal spot sizes, different methods are described in

EN 12543-1, EN 12543-2, EN 12543-3, EN 12543-4 and EN 12543-5.

The pinhole method (EN 12543-2) is intended for effective focal spot sizes above 0,1 mm and mainly

used for sealed standard and mini focus tubes.

The edge method of EN 12543-4 is intended for field applications when the users have to observe the

effective focal spot on a regular basis and the pinhole method is non-practical.

The edge measurement method of EN 12543-5 is intended for measurement of effective focal spot sizes

between 5 µm and 300 µm and mainly for the use with µ-Focus tubes (up to 100 µm) and mini focus

tubes with spot sizes of 100 µm to 300 µm.

In the overlapping ranges, the different standard parts provide comparable values within ± 20 %

tolerance.
ASTM E1165 describes the same pinhole procedure.
---------------------- Page: 6 ----------------------
SIST EN 12543-2:2021
EN 12543-2:2021 (E)
1 Scope

This document specifies a method for the measurement of effective focal spot dimensions above 0,1 mm

of X-ray systems up to and including 1000 kV tube voltage by means of the pinhole camera method with

digital evaluation. The tube voltage applied for this measurement is restricted to 200 kV for visual film

evaluation and may be selected higher than 200 kV if digital detectors are used.

The imaging quality and the resolution of X-ray images depend highly on the characteristics of the

effective focal spot, in particular the size and the two dimensional intensity distribution as seen from

the detector plane. This method compared to the others in the EN 12543 series allows to obtain an

image of the focal spot and to see the state of it (e.g. cratering of the anode).

This test method provides instructions for determining the effective size (dimensions) of standard

(macro focal spots) and mini focal spots of industrial X-ray tubes. This determination is based on the

measurement of an image of a focal spot that has been radiographically recorded with a “pinhole”

technique and evaluated with a digital method.

For the characterization of commercial X-ray tube types (i.e. for advertising or trade) it is advised that

the specific FS (Focal spot) values of Annex A are used.
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.

EN 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

(ISO 19232-5)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
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.

Note 2 to entry: See Figure 3, Key 7.
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.

Note 2 to entry: See Figure 3, Key 4.
---------------------- Page: 7 ----------------------
SIST EN 12543-2:2021
EN 12543-2:2021 (E)
3.3
effective focal spot size
focal spot size measured in accordance with this document
3.4
nominal focal spot size

characteristic value for X-ray tubes having measured spot sizes within a defined range

Note 1 to entry: Annex A, Table A.1, defines the ranges of measured spot sizes in reference to the nominal value SS

for characterization of X-ray tubes.
3.5
Focal spot class
number used to classify X-ray tubes based on the nominal focal spot size
3.6
basic spatial resolution of a detector
detector

smallest degree of visible detail within a digital image, determined with the duplex wire image quality

indicator (IQI) according to EN ISO 19232-5 located on the detector (magnification = 1), from the

smallest number of the duplex wire pair with less than 20% modulation depth in a linearized profile

and it corresponds to ½ of the detector unsharpness
4 Test equipment
4.1 Essential characteristics of the pinhole

The pinhole camera shall consist of a diaphragm with a pinhole having following essential dimensions P

and H according to Table 1 dependent from the effective focal spot size.
Table 1 — Dimensions of the pinhole
Focal spot size Diameter P Height H
mm µm µm
0,1 to 0,3 10 ± 5 20 ± 5
> 0,3 to 1,0 30 ± 5 75 ± 10
> 1,0 100 ± 5 500 ± 10
The essential dimensions P and H are shown in Figure 1.
---------------------- Page: 8 ----------------------
SIST EN 12543-2:2021
EN 12543-2:2021 (E)
Dimensions in millimetres
Key
1 focal spot
Figure 1 — Essential dimensions of a pinhole diaphragm

The pinhole diaphragm shall be made of tungsten or of a similar absorbent material (e.g. gold, platinum,

tantalum or related alloys).
4.2 Alignment and position of the pinhole camera

The angle between the beam direction and the pinhole axis (see Figure 2) shall be smaller than ± 1,5 °.

When deviating from Figure 2, the direction of the beam shall be indicated.
Key
1 focal spot
2 beam direction
3 maximum deviation of the axis of the pinhole
Figure 2 — Alignment of the pinhole camera
---------------------- Page: 9 ----------------------
SIST EN 12543-2:2021
EN 12543-2:2021 (E)

The incident face of the pinhole diaphragm shall be placed at a distance m from the focal spot so that

the variation of the magnification over the extension of the actual focal spot does not exceed ± 5 % in

the beam direction. In no case shall this distance be less than 100 mm.
4.3 Position of the radiographic image detector

The radiographic image detector [film, imaging plate (CR) or digital detector array (DDA)] shall be

placed normal to the beam direction at a distance n from the incident face of the pinhole diaphragm

determined from the applicable magnification according to Figure 3 and Table 2.
Key
1 plane of anode
2 reference plane
3 radiographic image detector
4 magnified length of the effective focal spot
5 beam direction
6 incident face of the diaphragm
7 physical length of the actual focal spot
n distance from pin hole to detector
m distance from focal spot centre to pin hole
Figure 3 — Beam direction dimensions and planes
---------------------- Page: 10 ----------------------
SIST EN 12543-2:2021
EN 12543-2:2021 (E)
Table 2 — Magnification for focal spot pinhole images
Distance between Distance between
Anticipated Focal Spot Minimum
Focal Spot and Pinhole and
Size d Magnification n/m
Pinhole m Detector n
a a
m m
0,1 to 1,0 5: 1 0,10 0,50
1,0 to 2,0 3: 1 0,25 0,75
> 2,0 1: 1 0,5 0,5

When using a technique that entails the use of enlargement factors and a 1 m focal spot to detector

distance (FDD = m+n) is not possible (see 5.1), the distance between the focal spot and the pinhole (m)

shall be adjusted to suit the actual focal spot to detector distance (FDD) used (for example, if a 600 mm

FDD is used, m shall be 100 mm for 5:1 enlargement, 150 mm for 3:1 enlargement, 300 mm for 1:1

enlargement, and the like).
4.4 Requirements on the radiographic image detector

Digital radiographic image detectors can be used instead of film, provided sensitivity, dy

...

SLOVENSKI STANDARD
oSIST prEN 12543-2:2019
01-junij-2019
Neporušitvene preiskave - Značilnosti goriščne površine v industrijskih
rentgenskih sistemih za neporušitveno preskušanje - 2. del: Metoda s kamero z
luknjico

Non-destructive testing - Characteristics of focal spots in industrial X-ray systems for use

in non-destructive testing - Part 2: Pinhole camera radiographic method
Zerstörungsfreie Prüfung - Charakterisierung von Brennflecken in Industrie-
Röntgenanlagen für die zerstörungsfreie Prüfung - Teil 2: Radiographisches
Lochkamera-Verfahren

Essais non destructifs - Caractéristiques des foyers émissifs des tubes radiogènes

industriels utilisés dans les essais non destructifs - Partie 2 : Méthode radiographique

par sténopé
Ta slovenski standard je istoveten z: prEN 12543-2
ICS:
19.100 Neporušitveno preskušanje Non-destructive testing
oSIST prEN 12543-2:2019 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
oSIST prEN 12543-2:2019
---------------------- Page: 2 ----------------------
oSIST prEN 12543-2:2019
DRAFT
EUROPEAN STANDARD
prEN 12543-2
NORME EUROPÉENNE
EUROPÄISCHE NORM
April 2019
ICS 19.100 Will supersede EN 12543-2:2008
English Version
Non-destructive testing - Characteristics of focal spots in
industrial X-ray systems for use in non-destructive testing
- Part 2: Pinhole camera radiographic method

Essais non destructifs - Caractéristiques des foyers Zerstörungsfreie Prüfung - Charakterisierung von

émissifs des tubes radiogènes industriels utilisés dans Brennflecken in Industrie-Röntgenanlagen für die

les essais non destructifs - Partie 2 : Méthode zerstörungsfreie Prüfung - Teil 2: Radiographisches

radiographique par sténopé Lochkamera-Verfahren

This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee

CEN/TC 138.

If this draft becomes a European Standard, 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.

This draft European Standard was established by CEN 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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,

Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,

Turkey and United Kingdom.

Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are

aware and to provide supporting documentation.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without

notice and shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2019 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 12543-2:2019 E

worldwide for CEN national Members.
---------------------- Page: 3 ----------------------
oSIST prEN 12543-2:2019
prEN 12543-2:2019 (E)
Contents Page

European foreword ...................................................................................................................................................... 3

Introduction .................................................................................................................................................................... 4

1 Scope .................................................................................................................................................................... 5

2 Normative references .................................................................................................................................... 5

3 Terms and definitions ................................................................................................................................... 5

4 Test equipment ................................................................................................................................................ 6

4.1 Essential characteristics of the pinhole .................................................................................................. 6

4.2 Alignment and position of the pinhole camera .................................................................................... 7

4.3 Position of the radiographic image detector ........................................................................................ 7

4.4 Requirements on the radiographic image detector ........................................................................... 9

4.5 Image processing equipment ..................................................................................................................... 9

4.6 Loading factors .............................................................................................................................................. 10

5 Measurement and determination of the focal spot size .................................................................. 10

5.1 Measurement procedure ............................................................................................................................ 10

5.2 Measurement with digital technique (preferred method) ............................................................ 11

5.3 Evaluation with digital technique using Integrated Line Profiles (ILP) ................................... 12

5.4 Measurement of effective focal spot size visually using film radiographs ............................... 14

6 Classification and result of focal spot size measurement .............................................................. 15

Annex A (informative) Values for the classification of X-ray tube focal spot sizes .............................. 16

Bibliography ................................................................................................................................................................. 18

---------------------- Page: 4 ----------------------
oSIST prEN 12543-2:2019
prEN 12543-2:2019 (E)
European foreword

This document (prEN 12543-2:2019) has been prepared by Technical Committee CEN/TC 138 “Non-

destructive testing”, the secretariat of which is held by AFNOR.
This document is currently submitted to the CEN Enquiry.
This document will supersede EN 12543-2:2008.
---------------------- Page: 5 ----------------------
oSIST prEN 12543-2:2019
prEN 12543-2:2019 (E)
Introduction

In order to cover the large range of effective focal spot sizes, four different methods are described in

EN 12543-2, EN 12543-4, EN 12543-5 and prEN 12543-6.

The pinhole method (EN 12543-2) is intended for effective focal spot sizes above 50 µm and mainly

sealed standard- and mini focus tubes.

The penetrameter method of EN 12543-4 is intended for field applications when the users have to

observe the effective focal spot on a regular basis and the pinhole method is non-practical.

The edge measurement method of EN 12543-5 is intended for measurement of effective focal spot sizes

between 5 µm and 300 µm and mainly for the use with µ-Focus tubes (up to 100 µm) and mini focus

tubes with spot sizes of 100 µm to 300 µm.

In the overlapping ranges, the different standard parts provide comparable values within ± 20 %

tolerance.
ASTM E1165 describes the same procedure.
---------------------- Page: 6 ----------------------
oSIST prEN 12543-2:2019
prEN 12543-2:2019 (E)
1 Scope

This document specifies a method for the measurement of effective focal spot dimensions above 0,1 mm

of X-ray systems up to and including 1000 kV tube voltage by means of the pinhole camera method with

digital evaluation. The tube voltage applied for this measurement is restricted to 200 kV for visual film

evaluation.

The imaging quality and the resolution of X-ray images depend highly on the characteristics of the

effective focal spot, in particular the size and the two dimensional intensity distribution as seen from

the detector plane.

This test method provides instructions for determining the effective size (dimensions) of standard

(macro focal spots) and mini focal spots of industrial X-ray tubes. This determination is based on the

measurement of an image of a focal spot that has been radiographically recorded with a “pinhole”

technique and evaluated with a digital method.

For the characterization of commercial X-ray tube types (i.e. for advertising or trade) it is advised that

the specific FS values of Annex A are used.
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.

EN 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

(ISO 19232-5)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1
actual focal spot

X-ray producing area of the target as viewed from a position perpendicular to the target surface

(see Figure 3)

Note 1 to entry: The actual focal spot is also called thermal focal spot in other literature.

3.2
effective focal spot

X-rays producing area of the target as viewed from the image plane of the detector (see Figure 3)

3.3
effective size of focal spot
focal spot size measured in accordance with this document
---------------------- Page: 7 ----------------------
oSIST prEN 12543-2:2019
prEN 12543-2:2019 (E)
3.4
basic spatial resolution of a detector
detector

smallest degree of visible detail within a digital image, determined with the duplex wire IQI according

to EN ISO 19232-5 located on the detector (magnification = 1), from the smallest number of the duplex

wire pair with less than 20% modulation depth in a linearized profile and it corresponds to ½ of the

detector image unsharpness
4 Test equipment
4.1 Essential characteristics of the pinhole

The pinhole camera shall consist of a diaphragm with a pinhole having following essential dimensions P

and H according to Table 1 dependent from the actual focal spot size.
Table 1 — Dimensions of the pinhole
Focal spot size Diameter P Height H
mm µm µm
0,1 to 0,3 10 ± 5 50 ± 5
> 0,3 to 1,0 30 ± 5 75 ± 10
> 1,0 100 ± 5 500 ± 10
The essential dimensions P and H are shown in Figure 1.
Dimensions in millimetres
Key
1 focal spot
Figure 1 — Essential dimensions of a pinhole diaphragm

The pinhole diaphragm shall be made of tungsten or of a similar absorbent material.

---------------------- Page: 8 ----------------------
oSIST prEN 12543-2:2019
prEN 12543-2:2019 (E)
4.2 Alignment and position of the pinhole camera

The angle between the beam direction and the pinhole axis (see Figure 2) shall be smaller than ± 1,5 °.

When deviating from Figure 2, the direction of the beam shall be indicated.
Key
1 focal spot
2 beam direction
3 maximum deviation of the axis of the pinhole
Figure 2 — Alignment of the pinhole camera

The incident face of the pinhole diaphragm shall be placed at a distance m from the focal spot so that

the variation of the magnification over the extension of the actual focal spot does not exceed ± 5 % in

the beam direction. In no case shall this distance be less than 100 mm.
4.3 Position of the radiographic image detector

The radiographic image detector (film, imaging plate or DDA) shall be placed normal to the beam

direction at a distance n from the incident face of the pinhole diaphragm determined from the

applicable magnification according to Figure 3 and Table 2.
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oSIST prEN 12543-2:2019
prEN 12543-2:2019 (E)
Key
1 plane of anode
2 reference plane
3 radiographic image detector
4 magnified length of the effective focal spot
5 beam direction
6 incident face of the diaphragm
7 physical length of the actual focal spot
Figure 3 — Beam direction dimensions and planes
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oSIST prEN 12543-2:2019
prEN 12543-2:2019 (E)
Table 2 — Magnification for focal spot pinhole images
Distance between Distance between
Anticipated Focal Spot Minimum
Focal Spot and Pinhole and
Size d Magnification
Pinhole m Detector n
a a
[mm] n/m [m] [m]
0,1 to 2,0 3: 1 0,25 0,75
> 2,0 1: 1 0,5 0,5

When using a technique that entails the use of enlargement factors and a 1 m focal spot to detector

distance (FDD = m+n) is not possible (see 7.1), the distance between the focal spot and the pinhole (m)

shall be adjusted to suit the actual focal spot to detector distance (FDD) used (for example, if a 600 mm

FDD is used, m shall be 150 mm for 3:1 enlargement, 300 mm for 1:1 enlargement, and the like).

4.4 Requirements on the radiographic image detector

Analogue or digital radiographic image detectors can be used, provided sensitivity, dynamic range and

detector unsharpness allow capturing of the full spatial size of the focal spot image without detector

detector

saturation. The maximum allowed basic spatial resolution (SR ) of the detector is determined from

the pinhole diameter P and magnification n/m. It is calculated according to Formula (1).

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