SIST EN 61331-1:2014
(Main)Protective devices against diagnostic medical X-radiation - Part 1: Determination of attenuation properties of materials
Protective devices against diagnostic medical X-radiation - Part 1: Determination of attenuation properties of materials
This part of IEC 61331 applies to materials in sheet form used for the manufacturing of
PROTECTIVE DEVICES against X-RADIATION of RADIATION QUALITIES generated with X-RAY TUBE
VOLTAGES up to 400 kV and gamma radiation emitted by radionuclides with photon energies
up to 1,3 MeV.
This Part 1 is not intended to be applied to PROTECTIVE DEVICES when these are to be checked
for the presence of their ATTENUATION properties before and after periods of use.
This Part 1 specifies the methods of determining and indicating the ATTENUATION properties of
the materials.
The ATTENUATION properties are given in terms of:
– ATTENUATION RATIO;
– BUILD-UP FACTOR;
– ATTENUATION EQUIVALENT;
together with, as appropriate, an indication of homogeneity and mass per unit area.
Ways of stating values of ATTENUATION properties in compliance with this part of the
International Standard are included.
Excluded from the scope of this International Standard are:
– methods for periodical checks of PROTECTIVE DEVICES, particularly of PROTECTIVE CLOTHING,
– methods of determining ATTENUATION by layers in the RADIATION BEAM, and
– methods of determining ATTENUATION for purposes of protection against IONIZING RADIATION
provided by walls and other parts of an installation
Strahlenschutz in der medizinischen Röntgendiagnostik - Teil 1: Bestimmung von Schwächungseigenschaften von Materialien
Dispositifs de protection radiologique contre les rayonnements X pour diagnostic médical - Partie 1: Détermination des propriétés d'atténuation des matériaux
L'IEC 61331:2014 s'applique aux matériaux en plaques utilisés pour la fabrication des dispositifs de protection radiologique contre les rayonnements X dont les qualités de rayonnement sont celles générées avec des hautes tensions radiogènes allant jusqu'à 400 kV et les rayonnements gamma émis par des radionucléides ayant une énergie photonique égale au plus à 1,3 MeV. La présente Partie 1 n'est pas prévue pour être appliquée aux dispositifs de protection radiologique lorsqu'il doit être procédé à la vérification de leurs propriétés d'atténuation avant et après les périodes d'utilisation. La présente Partie 1 spécifie les méthodes de détermination et d'indication des propriétés d'atténuation des matériaux. Les propriétés d'atténuation sont indiquées dans les termes suivants:
- indice d'atténuation;
- facteur d'accumulation; et
- équivalent d'atténuation, avec, selon le cas, une indication d'homogénéité et de masse surfacique. Les manières d'énoncer les valeurs des propriétés d'atténuation en conformité avec la présente partie de la Norme internationale sont incluses. Les méthodes suivantes sont exclues du domaine d'application de la présente Norme internationale:
- les méthodes relatives aux vérifications périodiques des dispositifs de protection radiologique, en particulier des vêtements de protection radiologique;
- les méthodes de détermination de l'atténuation procurée par les couches dans le faisceau de rayonnement, et les méthodes de détermination de l'atténuation à des fins de protection contre les rayonnements ionisants procurée par les murs et autres parties structurelles d'une installation.
Sredstva za zaščito pred rentgenskim sevanjem pri medicinski diagnostiki - 1. del: Ugotavljanje slabilnih lastnosti materialov (IEC 61331-1:2014)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN 61331-1:2014
01-december-2014
1DGRPHãþD
SIST EN 61331-1:2002
6UHGVWYD]D]DãþLWRSUHGUHQWJHQVNLPVHYDQMHPSULPHGLFLQVNLGLDJQRVWLNLGHO
8JRWDYOMDQMHVODELOQLKODVWQRVWLPDWHULDORY ,(&
Protective devices against diagnostic medical X-radiation - Part 1: Determination of
attenuation properties of materials
Dispositifs de protection radiologique contre les rayonnements X pour diagnostic médical
- Partie 1: Détermination des propriétés d'atténuation des matériaux
Ta slovenski standard je istoveten z: EN 61331-1:2014
ICS:
11.040.50 Radiografska oprema Radiographic equipment
13.280 Varstvo pred sevanjem Radiation protection
SIST EN 61331-1:2014 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN 61331-1:2014
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SIST EN 61331-1:2014
EUROPEAN STANDARD EN 61331-1
NORME EUROPÉENNE
EUROPÄISCHE NORM
October 2014
ICS 11.040.50 Supersedes EN 61331-1:2002
English Version
Protective devices against diagnostic medical X-radiation - Part
1: Determination of attenuation properties of materials
(IEC 61331-1:2014)
Dispositifs de protection radiologique contre les Strahlenschutz in der medizinischen Röntgendiagnostik -
rayonnements X pour diagnostic médical - Partie 1: Teil 1: Bestimmung von Schwächungseigenschaften von
Détermination des propriétés d'atténuation des matériaux Materialien
(CEI 61331-1:2014) (IEC 61331-1:2014)
This European Standard was approved by CENELEC on 2014-06-11. CENELEC 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 CENELEC 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 CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the
same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2014 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN 61331-1:2014 E
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SIST EN 61331-1:2014
EN 61331-1:2014 - 2 -
Foreword
The text of document 62B/936/FDIS, future edition 2 of IEC 61331-1, prepared by SC 62B, "Diagnostic
imaging equipment", of IEC TC 62, "Electrical equipment in medical practice " was submitted to the IEC-
CENELEC parallel vote and approved by CENELEC as EN 61331-1:2014.
The following dates are fixed:
(dop) 2015-04-24
• latest date by which the document has
to be implemented at national level by
publication of an identical national
standard or by endorsement
• latest date by which the national (dow) 2017-06-11
standards conflicting with the
document have to be withdrawn
This document supersedes EN 61331-1:2002.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC [and/or CEN] shall not be held responsible for identifying any or all such patent
rights.
Endorsement notice
The text of the International Standard IEC 61331-1:2014 was approved by CENELEC as a European
Standard without any modification.
IEC 61331-3 NOTE Harmonised as EN 61331-3.
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SIST EN 61331-1:2014
- 3 - EN 61331-1:2014
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
NOTE 1 When an International Publication has been modified by common modifications, indicated by (mod), the relevant EN/HD
applies.
NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is available here:
www.cenelec.eu.
Publication Year Title EN/HD Year
IEC 60601-1 2005 Medical electrical equipment -- Part 1: EN 60601-1 2006
General requirements for basic safety and
essential performance
+EN 60601- 2010
1:2006/corrigendum
Mar. 2010
+AC 2014
+A11 2011
+A1 2012 +A1 2013
IEC 60601-1-3 2008 Medical electrical equipment -- Part 1-3: EN 60601-1-3 2008
General requirements for basic safety and
essential performance - Collateral Standard:
Radiation protection in diagnostic X-ray
equipment
+EN 60601-1- 2010
3:2008/corrigendum
Mar. 2010
+A1 2013 +A1 2013
+AC 2014
IEC/TR 60788 2004 Medical electrical equipment - Glossary of - -
defined terms
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SIST EN 61331-1:2014
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SIST EN 61331-1:2014
IEC 61331-1
®
Edition 2.0 2014-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Protective devices against diagnostic medical X-radiation –
Part 1: Determination of attenuation properties of materials
Dispositifs de protection radiologique contre les rayonnements X pour
diagnostic médical –
Partie 1: Détermination des propriétés d’atténuation des matériaux
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX T
ICS 11.040.50 ISBN 978-2-8322-1562-3
Warning! Make sure that you obtained this publication from an authorized distributor.
Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.
® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale
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SIST EN 61331-1:2014
– 2 – IEC 61331-1:2014 © IEC 2014
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 7
4 Methods to determine the ATTENUATION RATIO . 7
4.1 General . 7
4.2 NARROW BEAM CONDITION . 7
4.2.1 General description . 7
4.2.2 AIR KERMA RATE measurements . 7
4.2.3 RADIATION QUALITIES and RADIATION DETECTOR . 8
4.2.4 Signal to noise condition . 9
4.2.5 ATTENUATION RATIO evaluation. 10
4.3 BROAD BEAM CONDITION . 10
4.3.1 General description . 10
4.3.2 AIR KERMA RATE measurements . 10
4.3.3 RADIATION QUALITIES and RADIATION DETECTOR . 10
4.3.4 Signal to noise condition . 11
4.3.5 ATTENUATION RATIO evaluation . 12
4.4 Inverse BROAD BEAM CONDITION . 12
4.4.1 General description . 12
4.4.2 AIR KERMA RATE measurements . 12
4.4.3 RADIATION QUALITIES and RADIATION DETECTOR . 13
4.4.4 Signal to noise condition . 14
4.4.5 ATTENUATION RATIO evaluation . 14
4.5 Calculation of the ATTENUATION RATIO for photon-emitting radionuclides . 14
4.5.1 Equation . 14
4.5.2 Decay data . 14
4.5.3 Mass ATTENUATION and mass energy-absorption coefficients . 14
4.5.4 Verification of the mass- ATTENUATION COEFFICIENTS of the test
material . 15
5 Determination of ATTENUATION properties . 16
5.1 ATTENUATION RATIO . 16
5.1.1 Determination . 16
5.1.2 Indication . 16
5.2 BUILD-UP FACTOR . 16
5.2.1 Determination . 16
5.2.2 Indication . 16
5.3 ATTENUATION EQUIVALENT . 16
5.3.1 Determination . 16
5.3.2 Indication . 17
5.4 LEAD EQUIVALENT . 17
5.4.1 Determination . 17
5.4.2 Indication . 17
5.5 LEAD EQUIVALENT class for a SPECIFIED range of RADIATION QUALITIES . 17
5.5.1 Materials. 17
5.5.2 Standard thicknesses . 17
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IEC 61331-1:2014 © IEC 2014 – 3 –
5.5.3 Conditions for assignment to a LEAD EQUIVALENT class . 17
5.5.4 Indication . 18
5.6 Homogeneity . 18
5.6.1 Determination . 18
5.6.2 Indication . 18
6 Statement of compliance . 18
Annex A (informative) Tables of ATTENUATION RATIOS, BUILD-UP FACTORS and first HALF-
VALUE LAYERS . 19
Bibliography . 24
Index of defined terms used in this International Standard . 25
Figure 1 – NARROW BEAM CONDITION . 9
Figure 2 – BROAD BEAM CONDITION . 11
Figure 3 – Inverse BROAD BEAM CONDITION . 13
Table 1 – Standard RADIATION QUALITIES for X-RAY BEAMS . 15
Table 2 – Standard gamma RADIATION QUALITIES according to ISO 4037-1 . 16
Table A.1 – ATTENUATION RATIOS F of lead thicknesses from 0,125 mm to 2 mm
N
calculated for RADIATION QUALITIES of Table 1 according to the formula given in 4.5.4. 20
Table A.2 – BUILD-UP FACTOR B measured for RADIATION QUALITIES of Table 1 according
to the formula given in 5.2.1 for lead thicknesses 0,25 mm, 0,35 mm and 0,50 mm . 21
Table A.3 – ATTENUATION RATIOS F of lead thicknesses from 0,125 mm to 7 mm
N
calculated for RADIATION QUALITIES of Tables 1 and 2 according to the formula given in
4.5.4 . 21
Table A.4 – First HALF-VALUE LAYERS in mm Al of RADIATION QUALITIES of Table 1 as a
function of additional lead filters of different thicknesses in the range from 0,125 mm
to 2 mm . 22
Table A.5 – First HALF-VALUE LAYERS in mm Cu of RADIATION QUALITIES of Table 1 as a
function of additional lead filters of different thicknesses in the range from 0,125 mm
to 4 mm . 23
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SIST EN 61331-1:2014
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INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
PROTECTIVE DEVICES AGAINST
DIAGNOSTIC MEDICAL X-RADIATION –
Part 1: Determination of attenuation properties of materials
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61331-1 has been prepared by subcommittee 62B: Diagnostic
imaging equipment, of IEC technical committee 62: Electrical equipment in medical practice.
This second edition cancels and replaces the first edition of IEC 61331-1, published in 1994.
It constitutes a technical revision. This second edition has been adapted to apply to the
present technology. In particular, this second edition is consistently applicable to lead- and
non-lead-containing materials. The essential changes and extensions are:
– extension of the scope to cover photon-emitting radionuclides;
– improved methods to determine the ATTENUATION RATIO;
– addition of the so-called inverse BROAD BEAM CONDITION;
– addition of a method to calculate the ATTENUATION RATIO of photon-emitting radionuclides;
– definition of new standard X- and gamma RADIATION QUALITIES used for testing;
– addition of the so-called LEAD EQUIVALENT class;
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SIST EN 61331-1:2014
IEC 61331-1:2014 © IEC 2014 – 5 –
– tables of ATTENUATION RATIOS, BUILD-UP FACTORS and first HALF-VALUE LAYERS for the
standard RADIATION QUALITIES filtered with different thicknesses of lead.
The text of this standard is based on the following documents:
FDIS Report on voting
62B/936/FDIS 62B/942/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
In this standard, the following print types are used:
– requirements and definitions: roman type;.
– informative material appearing outside of tables, such as notes, examples and references: in smaller type.
Normative text of tables is also in a smaller type;
– TERMS DEFINED IN CLAUSE 3 OF THIS STANDARD OR AS NOTED: SMALL CAPS.
The verbal forms used in this standard conform to usage described in Annex H of the ISO/IEC
Directives, Part 2. For the purposes of this standard, the auxiliary verb:
– “shall” means that compliance with a requirement or a test is mandatory for compliance
with this standard;
– “should” means that compliance with a requirement or a test is recommended but is not
mandatory for compliance with this standard;
– “may” is used to describe a permissible way to achieve compliance with a requirement or
test.
A list of all parts of the IEC 61331 series, published under the general title Protective devices
against diagnostic medical X-radiation, can be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
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PROTECTIVE DEVICES AGAINST
DIAGNOSTIC MEDICAL X-RADIATION –
Part 1: Determination of attenuation properties of materials
1 Scope
This part of IEC 61331 applies to materials in sheet form used for the manufacturing of
PROTECTIVE DEVICES against X-RADIATION of RADIATION QUALITIES generated with X-RAY TUBE
VOLTAGES up to 400 kV and gamma radiation emitted by radionuclides with photon energies
up to 1,3 MeV.
This Part 1 is not intended to be applied to PROTECTIVE DEVICES when these are to be checked
for the presence of their ATTENUATION properties before and after periods of use.
This Part 1 specifies the methods of determining and indicating the ATTENUATION properties of
the materials.
The ATTENUATION properties are given in terms of:
– ATTENUATION RATIO;
– BUILD-UP FACTOR;
– ATTENUATION EQUIVALENT;
together with, as appropriate, an indication of homogeneity and mass per unit area.
ATTENUATION properties in compliance with this part of the
Ways of stating values of
International Standard are included.
Excluded from the scope of this International Standard are:
– methods for periodical checks of PROTECTIVE DEVICES, particularly of PROTECTIVE CLOTHING,
– methods of determining ATTENUATION by layers in the RADIATION BEAM, and
– methods of determining ATTENUATION for purposes of protection against IONIZING RADIATION
provided by walls and other parts of an installation.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 60601-1:2005, Medical electrical equipment – Part 1: General requirements for basic
safety and essential performance
IEC 60601-1:2005/AMD1:2012
IEC 60601-1-3:2008, Medical electrical equipment – Part 1-3: General requirements for basic
safety and essential performance – Collateral Standard: Radiation protection in diagnostic X-
ray equipment
IEC 60601-1-3:2008/AMD1:2013
IEC/TR 60788:2004, Medical electrical equipment – Glossary of defined terms
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SIST EN 61331-1:2014
IEC 61331-1:2014 © IEC 2014 – 7 –
1
Monographie BIPM-5:2013, Table of Radionuclides
NISTIR 5632:2004, Tables of X-Ray Mass Attenuation Coefficients and Mass Energy-
Absorption Coefficients (version 1.4) [on-line, cited 2014-01-30] Available at
2
http://www.nist.gov/pml/data/xraycoef/]
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC/TR 60788:2004,
IEC 60601-1:2005 and IEC 60601-1:2005/AMD 1:2012, IEC 60601-1-3:2008 and IEC 60601-
1-3:2008/AMD1:2013 and the following apply.
3.1
ATTENUATION RATIO
ratio of the value of a SPECIFIED RADIATION QUANTITY in the centre of a SPECIFIED RADIATION
BEAM of SPECIFIED RADIATION QUALITY, with the attenuating material under consideration
outside the beam, to the value at the same position and under the same conditions with this
attenuating material placed in the beam
4 Methods to determine the ATTENUATION RATIO
4.1 General
There are four different conditions described in this standard to determine ATTENUATION
RATIOS, F:
F ATTENUATION RATIO measured with a NARROW BEAM CONDITION (4.2)
N
F ATTENUATION RATIO measured with a BROAD BEAM CONDITION (4.3)
B
F ATTENUATION RATIO measured with an inverse BROAD BEAM CONDITION (4.4)
IB
F ATTENUATION RATIO calculated for a photon-emitting radionuclide, R (4.5)
N,R
4.2 NARROW BEAM CONDITION
4.2.1 General description
The ATTENUATION RATIO F for a given test material (or test object) shall be measured
N
according to the arrangement for NARROW BEAM CONDITION as shown in Figure 1. This
arrangement is designed to measure the ATTENUATION of the X-RAY BEAM only due to primary
photons. The probability that secondary photons such as fluorescence photons or Compton
scattered photons from the test object reach the RADIATION DETECTOR is minimized. The
aperture in the DIAPHRAGM shall be just large enough to produce the smallest beam covering
the radiation detector. An additional DIAPHRAGM (number 5 in Figure 1) shall be used to shield
the RADIATION DETECTOR from SCATTERED RADIATION produced in the test object. The distance a
from the test object to the reference point of the RADIATION DETECTOR on the beam axis shall
be at least ten times the diameter d of the detector or ten times the diameter t of the
RADIATION BEAM at the distal surface of the test object , whatever is larger, i.e. a ≥ 10 max(d,t).
The minimal distance of the wall or the floor from the detector (position 6 in the Figure 1) in
the direction of the beam shall be 700 mm.
4.2.2 AIR KERMA RATE measurements
The AIR KERMA RATE shall be measured under three different conditions with the same
RADIATION DETECTOR at the same position, where
______________
1
Bureau International de Poids et Mesures, Pavillon de Breteeuil, F-92310 Sèvres, ISBN 92-822-2204-7 (set).
2
National Institute of Standards and Technology (NIST), U.S.Department of Commerce.
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denotes the AIR KERMA RATE without the test object in the RADIATION BEAM;
K
0
the AIR KERMA RATE with the test object in the RADIATION BEAM;
K
1
the AIR KERMA RATE with the test object in the beam replaced by a sheet of material of
K
B
5
the same shape with an ATTENUATION RATIO greater than 10
.
The same constant dose rate of the primary beam shall be used for the three measurements.
If the mean dose rate of the primary beam varies by more than 0,2 % during the
measurements, a monitor shall be used to normalize the three measurements to the same
primary beam dose rate.
4.2.3 RADIATION QUALITIES and RADIATION DETECTOR
The RADIATION QUALITIES used for the measurements shall be selected from Table 1 . The
RADIATION DETECTOR shall be calibrated in terms of AIR KERMA. The quotient K divided by K
0 1
shall be known with a relative standard uncertainty not more than 2 %.
NOTE The AIR KERMA RESPONSE of the RADIATION DETECTOR can be measured with e.g. NARROW BEAM qualities
and the RESPONSE can be plotted as a function of Al or Cu HALF-VALUE LAYERS (HVL). Tables A.4 and A.5 of this
standard can be used to look up the approximate Al or Cu HVL of the non-attenuated and attenuated beams. The
AIR KERMA RESPONSE in the actual beam can then be evaluated from the plot.
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IEC 61331-1:2014 © IEC 2014 – 9 –
1
2
3
4
5
t
6
d
IEC 1444/14
1 DIAPHRAGM
2 Beam filtration
3 Beam-limiting DIAPHRAGM
4 Test object
5 DIAPHRAGM
6 Radiation detector
Condition: a ≥ 10 max(d,t)
Figure 1 – NARROW BEAM CONDITION
4.2.4 Signal to noise condition
The following condition shall be fulfilled:
K ≥ 10K
1 B
a
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4.2.5 ATTENUATION RATIO evaluation
The ATTENUATION RATIO F shall be evaluated as:
N
K −K
0 B
F =
N
K −K
1 B
4.3 BROAD BEAM CONDITION
4.3.1 General description
The ATTENUATION RATIO F for a given test material (or test object) shall be measured
B
according to the arrangement for BROAD BEAM CONDITION as shown in Figure 2. This
arrangement is designed to measure the ATTENUATION of the x-ray beam if secondary photons
emitted by the material sample are included in the detection of the attenuated beam. The
probability that secondary photons such as fluorescence photons or Compton scattered
photons from the test object reach the RADIATION DETECTOR is maximized. The distance a,
from the focal spot to the radiation exit plane of the test object shall be at least three times
the diameter d, of the beam limiting aperture, i.e. a ≥ 3d. The aperture diameter d shall be at
least 10 times greater than the distance b, of the reference point of the RADIATION DETECTOR
from the surface of the test object, i.e. d ≥ 10b. b shall be chosen as small as possible in
order to minimize the ATTENUATION of secondary photons by the amount of air between the
...
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