SIST EN 60544-2:2012

Electrical insulating materials - Guide for determining of the effects of ionizing radiation on insulating materials - Part 2: Procedures for irradiation and test

This Part of IEC 60544 specifies the controls maintained over the exposure conditions during and after the irradiation of insulating materials with ionizing radiation prior to the determination of radiation-induced changes in physical or chemical properties. This standard specifies a number of potentially significant irradiation conditions as well as various parameters which can influence the radiation-induced reactions under these conditions. The objective of this standard is to emphasize the importance of selecting suitable specimens, exposure conditions and test methods for determining the effect of radiation on appropriately chosen properties. Since many materials are used either in air or in inert environments, standard exposure conditions are recommended for both of these situations. It should be noted that this standard does not consider measurements which are performed during the irradiation.

Elektroisolierstoffe - Bestimmung der Auswirkungen ionisierender Strahlung auf Isolierstoffe - Teil 2: Verfahren zur Bestrahlung und Prüfung

Matériaux isolants électriques - Guide pour la détermination des effets des rayonnements ionisant sur les matériaux isolants - Partie 2: Méthodes d'irradiation et d'essai

La CEI 60544-2:2012 spécifie d'abord les contrôles exercés sur les conditions d'exposition pendant et après l'irradiation de matériaux isolants par des rayonnements ionisants, avant de déterminer les changements de propriétés physiques ou chimiques induits par rayonnement. Cette norme discute certaines des principales conditions d'irradiation possibles d'une importance significative et spécifie les divers paramètres qui peuvent influer sur les réactions induites par rayonnement dans ces conditions. L'objectif de la présente norme est de démontrer l'importance du choix d'échantillons, de conditions d'exposition et de méthodes d'essai appropriés pour déterminer les effets des rayonnements sur des propriétés convenablement choisies. Comme un grand nombre de matériaux peuvent être utilisés soit dans l'air, soit dans des environnements inertes, des conditions normales d'exposition sont recommandées pour chacune de ces situations. Il convient de noter que cette norme ne prend pas en compte les mesures réalisées pendant l'irradiation. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:   - alignement avec des normes récemment élaborées au sein du SC 45A, ainsi qu'avec d'autres parties de la série CEI 60544.

Električni izolacijski materiali - Navodilo za ugotavljanje učinkov ionizirnega sevanja na izolacijske materiale - 2. del: Postopki za obsevanje in preskušanje

Ta del standarda IEC 60544 določa nadzor nad pogoji izpostavljenosti med obsevanjem izolacijskih materialov z ionizirajočim sevanjem in po njem, preden se določijo spremembe, ki so posledica sevanja, v okviru fizikalnih in kemičnih lastnosti. Ta standard določa število potencialno pomembnih pogojev obsevanja in različne parametre, ki lahko vplivajo na reakcije, ki jih povzroči obsevanje, pod temi pogoji. Cilj tega standarda je poudariti pomen izbire ustreznih vzorcev, pogojev izpostavljenosti in preizkusnih metod za določanje učinka obsevanja na ustrezno izbrane lastnosti. Ker se veliko materialov uporablja v zraku ali v inertnih okoljih, so za obe navedeni vrsti okoliščin priporočljivi standardni pogoji izpostavljenosti. V tem standardu niso obravnavane meritve, ki se izvajajo med obsevanjem.

General Information

• Status: Published
• Publication Date: 29-Oct-2012
• ICS: 29.035.01 - Insulating materials in general
• Technical Committee: IIZS - Insulating materials and systems
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 25-Oct-2012
• Due Date: 30-Dec-2012
• Completion Date: 30-Oct-2012
• Ref Project: EN 60544-2:2012 - Electrical insulating materials - Determination of the effects of ionizing radiation on insulating materials - Part 2: Procedures for irradiation and test

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN 60544-2:2012
01-december-2012
(OHNWULþQLL]RODFLMVNLPDWHULDOL1DYRGLOR]DXJRWDYOMDQMHXþLQNRYLRQL]LUQHJD
VHYDQMDQDL]RODFLMVNHPDWHULDOHGHO3RVWRSNL]DREVHYDQMHLQSUHVNXãDQMH
Electrical insulating materials - Guide for determining of the effects of ionizing radiation
on insulating materials - Part 2: Procedures for irradiation and test
Matériaux isolants électriques - Guide pour la détermination des effets des
rayonnements ionisant sur les matériaux isolants - Partie 2: Méthodes d'irradiation et
d'essai
Ta slovenski standard je istoveten z: EN 60544-2:2012
ICS:
29.035.01 Izolacijski materiali na Insulating materials in
splošno general
SIST EN 60544-2:2012 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 60544-2:2012

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SIST EN 60544-2:2012

EUROPEAN STANDARD
EN 60544-2

NORME EUROPÉENNE
October 2012
EUROPÄISCHE NORM

ICS 17.240; 29.035.01


English version


Electrical insulating materials -
Determination of the effects of ionizing radiation on insulating materials -
Part 2: Procedures for irradiation and test
(IEC 60544-2:2012)


Matériaux isolants électriques -  Elektroisolierstoffe -
Détermination des effets des Bestimmung der Auswirkungen
rayonnements ionisants ionisierender Strahlung auf Isolierstoffe -
sur les matériaux isolants - Teil 2: Verfahren zur Bestrahlung und
Partie 2: Méthodes d'irradiation et d'essai Prüfung
(CEI 60544-2:2012) (IEC 60544-2:2012)




This European Standard was approved by CENELEC on 2012-08-13. 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.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

Management Centre: Avenue Marnix 17, B - 1000 Brussels


© 2012 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 60544-2:2012 E

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SIST EN 60544-2:2012
EN 60544-2:2012 - 2 -
Foreword
The text of document 112/208/FDIS, future edition 3 of IEC 60544-2, prepared by IEC/TC 112
"Evaluation and qualification of electrical insulating materials and systems" was submitted to the
IEC-CENELEC parallel vote and approved by CENELEC as EN 60544-2:2012.
The following dates are fixed:
(dop) 2013-05-13
• latest date by which the document has
to be implemented at national level by
publication of an identical national
standard or by endorsement
(dow) 2015-08-13
• latest date by which the national
standards conflicting with the
document have to be withdrawn

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 60544-2:2012 was approved by CENELEC as a European
Standard without any modification.

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SIST EN 60544-2:2012
- 3 - EN 60544-2:2012
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  When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD
applies.

Publication Year Title EN/HD Year

IEC 60093 - Methods of test for volume resistivity and HD 429 S1 -
surface resistivity of solid electrical insulating
materials


IEC 60167 - Methods of test for the determination of the HD 568 S1 -
insulation resistance of solid insulating
materials


IEC 60212 - Standard conditions for use prior to and EN 60212 -
during the testing of solid electrical insulating
materials


IEC 60243-1 - Electrical strength of insulating materials - EN 60243-1 -
Test methods -
Part 1: Tests at power frequencies


IEC 60544-1 - Electrical insulating materials - EN 60544-1 -
Determination of the effects of ionizing
radiation -
Part 1: Radiation interaction and dosimetry


IEC 60544-4 - Electrical insulating materials - EN 60544-4 -
Determination of the effects of ionizing
radiation -
Part 4: Classification system for service in
radiation environments


ISO 37 - Rubber, vulcanized or thermoplastic - - -
Determination of tensile stress-strain
properties


ISO 48 - Rubber, vulcanized or thermoplastic - - -
Determination of hardness (hardness
between 10 IRHD and 100 IRHD)

ISO 178 - Plastics - Determination of flexural EN ISO 178 -
properties


ISO 179 Series Plastics - Determination of Charpy impact EN ISO 179 Series
properties


ISO 527 Series Plastics - Determination of tensile properties EN ISO 527 Series



ISO 815 Series Rubber, vulcanized or thermoplastic - -
Determination of compression set


ISO 868 - Plastics and ebonite - Determination of EN ISO 868 -
indentation hardness by means of a
durometer (Shore hardness)

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SIST EN 60544-2:2012

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SIST EN 60544-2:2012



IEC 60544-2

®


Edition 3.0 2012-07




INTERNATIONAL



STANDARD




NORME



INTERNATIONALE











Electrical insulating materials – Determination of the effects of ionizing radiation

on insulating materials –

Part 2: Procedures for irradiation and test




Matériaux isolants électriques – détermination des effets des rayonnements

Ionisants sur les matériaux isolants –


Partie 2: Méthodes d'irradiation et d'essai













INTERNATIONAL

ELECTROTECHNICAL

COMMISSION


COMMISSION

ELECTROTECHNIQUE

PRICE CODE
INTERNATIONALE

CODE PRIX S


ICS 17.240; 29.035.01 ISBN 978-2-83220-223-4



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 60544-2:2012
– 2 – 60544-2 © IEC:2012
CONTENTS

FOREWORD . 4
INTRODUCTION . 6
1 Scope . 8
2 Normative references . 8
3 Irradiation . 9
3.1 Type of radiation and dosimetry . 9
3.2 Irradiation conditions . 10
3.3 Sample preparation . 10
3.4 Irradiation procedures . 10
3.4.1 Irradiation dose-rate control . 10
3.4.2 Irradiation temperature control . 10
3.4.3 Irradiation in air . 11
3.4.4 Irradiation in a medium other than air . 11
3.4.5 Irradiation in a vacuum . 11
3.4.6 Irradiation at high pressure . 12
3.4.7 Irradiation during mechanical stressing . 12
3.4.8 Irradiation during electrical stressing . 12
3.4.9 Combined irradiation procedures . 12
3.5 Post-irradiation effects . 12
3.6 Specified irradiation conditions . 12
4 Test . 12
4.1 General . 12
4.2 Test procedures . 13
4.3 Evaluation criteria . 13
4.3.1 End-point criteria . 13
4.3.2 Values of the absorbed dose . 14
4.4 Evaluation . 14
5 Report . 15
5.1 General . 15
5.2 Material . 15
5.3 Irradiation . 15
5.4 Test . 15
5.5 Results . 15
Annex A (informative) Examples of test reports . 16
Bibliography . 21

Figure A.1 – Change of mechanical properties as a function of absorbed dose for
magnetic coil insulation . 17
Figure A.2 – Breakdown voltage of insulating tape as a function of absorbed dose . 20

Table 1 – Critical properties and end-point criteria to be considered in evaluating the
classification of insulating materials in radiation environments . 14
Table A.1 – Example 1 – Magnetic coil insulation . 16
Table A.2 – Example 2 – Cable insulation . 18

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SIST EN 60544-2:2012
60544-2 © IEC:2012 – 3 –
Table A.3 – Example 3 – Insulating tape . 19

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SIST EN 60544-2:2012
– 4 – 60544-2 © IEC:2012
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________

ELECTRICAL INSULATING MATERIALS –
DETERMINATION OF THE EFFECTS OF IONIZING
RADIATION ON INSULATING MATERIALS –

Part 2: Procedures for irradiation and test


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 60544-2 has been prepared by IEC technical committee 112:
Evaluation and qualification of electrical insulating materials and systems.
This third edition cancels and replaces the second edition, published in 1991, and constitutes
a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
– alignment with standards recently developed by SC 45A as well as with other parts in the
IEC 60544 series.

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SIST EN 60544-2:2012
60544-2 © IEC:2012 – 5 –
The text of this standard is based on the following documents:
FDIS Report on voting
112/208/FDIS 112/216/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.
A list of all parts of the IEC 60544 series can be found, under the general title Electrical
insulating materials – Determination of the effects of ionizing radiation on insulating materials,
on the IEC website.
Future standards in this series will carry the new general title as cited above. Titles of existing
standards in this series will be updated at the time of the next edition.
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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SIST EN 60544-2:2012
– 6 – 60544-2 © IEC:2012
INTRODUCTION
When selecting insulating materials for applications in radiation environments, the component
designers should have available reliable test data to compare candidate materials. To be
meaningful, the performance data should be obtained on each material by standardized
procedures, and the procedures should be designed to demonstrate the influence that
variations of the service conditions have on the significant properties. This point is of
particular concern where in normal service conditions low dose rates exist and where the
insulation materials have been selected from radiation endurance data obtained from tests
conducted at high dose rates.
Environmental conditions shall be well controlled and documented during the measurement of
radiation effects. Important environmental parameters include temperature, reactive medium
and mechanical and electrical stresses present during the irradiation. If air is present,
radiation-induced species can enter into reactions with oxygen that would not occur in its
absence. This is responsible for an observed influence of the absorbed dose rate for certain
types of polymers if irradiated in air. As a result, the resistance may be several orders of
magnitude lower than when the sample is irradiated under vacuum or in the presence of inert
gas. This is generally called the "dose-rate effect", which is described and reviewed in
1
references [1] to [14] .
NOTE For the user of this Part of IEC 60544 who wants to go into more detail, the cited references are listed in
the Bibliography. Where these are not publications in internationally available journals, addresses where the cited
scientific reports can be obtained are given at the end of the references.
The irradiation time can become relevant because of time-dependent complications caused by:
a) physical effects such as diffusion-limited oxidation [8], [10]; and
b) chemical phenomena such as rate-determining hydroperoxide breakdown reactions [10],
[14].
Typical diffusion-limited effects are commonly observed in radiation studies of polymers in air.
Their importance depends upon the interrelationship of the geometry of the polymer with the
oxygen permeation and consumption rates, both of which depend upon temperature [10]. This
means that the irradiation of thick samples in air may result in oxidation only near the air-
exposed surfaces of the sample, resulting in material property changes similar to those
obtained by irradiation in an oxygen-free environment. Therefore, when the material is to be
used in air for a long period of time at a low dose rate, depositing the same total dose at a
high dose rate in a short exposure period may not determine its durability. Previous
experiments or considerations of sample thickness combined with estimates of oxygen
permeation and consumption rates [8], [10] may eliminate such concerns. A technique that
may be useful for eliminating oxygen diffusion effects by increasing the surrounding oxygen
pressure is under investigation [8].
Radiation-induced reactions will be influenced by temperature. An increase in reaction rate
with temperature can result in a synergistic effect of radiation and heat. In the case of the
more commonly used thermal ageing prediction, the Arrhenius method is employed; this
makes use of an equation based on fundamental chemical kinetics. Despite considerable
ongoing investigations of radiation ageing methodologies, this field is much less developed [9].
General equations involving dose, time, Arrhenius activation energy, dose rate and
temperature are being tested for modelling of ageing experiments [10-12]. It should be noted
that sequential application of radiation and heat, as it is frequently practised, can give very
different results depending on the order in which they are performed, and that synergistic
effects may not be properly simulated [13], [14].
The electrical and mechanical properties required of insulating materials and the acceptable
amount of radiation-induced changes are so varied that it is not possible to establish
___________
1
 References in square brackets refer to the bibliography.

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SIST EN 60544-2:2012
60544-2 © IEC:2012 – 7 –
acceptable properties within the framework of a recommendation. The same holds for the
irradiation conditions. Therefore, this standard recommends only a few properties and
irradiation conditions which previous experience has shown to be appropriate. The properties
recommended are those that are especially sensitive to radiation. For a specific application,
other properties may have to be selected.
Part 1 of IEC 60544 constitutes an introduction dealing very broadly with the problems
involved in evaluating radiation effects. It also provides a guide to dosimetry terminology,
several methods of determining the exposure and absorbed dose, and methods of calculating
the absorbed dose in any specific material from the dosimetry method applied. The present
part describes procedures for irradiation and test. Part 4 of IEC 60544 defines a classification
system to categorize the radiation endurance of insulating materials. It provides a set of
parameters characterizing the suitability for radiation service. It is a guide for the selection,
indexing and specification of insulating materials. The earlier Part 3 of IEC 60544 has been
incorporated into the present Part 2.

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SIST EN 60544-2:2012
– 8 – 60544-2 © IEC:2012
ELECTRICAL INSULATING MATERIALS –
DETERMINATION OF THE EFFECTS OF IONIZING
RADIATION ON INSULATING MATERIALS –

Part 2: Procedures for irradiation and test



1 Scope
This Part of IEC 60544 specifies the controls maintained over the exposure conditions during
and after the irradiation of insulating materials with ionizing radiation prior to the
determination of radiation-induced changes in physical or chemical properties.
This standard specifies a number of potentially significant irradiation conditions as well as
various parameters which can influence the radiation-induced reactions under these
conditions.
The objective of this standard is to emphasize the importance of selecting suitable specimens,
exposure conditions and test methods for determining the effect of radiation on appropriately
chosen properties. Since many materials are used either in air or in inert environments,
standard exposure conditions are recommended for both of these situations.
It should be noted that this standard does not consider measurements which are performed
during the irradiation.
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 60093, Methods of test for volume resistivity and surface resistivity of solid electrical
insulating materials
IEC 60167, Methods of test for the determination of the insulation resistance of solid
insulating materials
IEC 60212, Standard conditions for use prior to and during the testing of solid electrical
insulating materials
IEC 60243-1, Electrical strength of insulating materials –Test methods – Part 1: Tests at
power frequencies
IEC 60544-1, Electrical insulating materials – Determination of the effects of ionizing radiation
– Part 1: Radiation interaction and dosimetry
IEC 60544-4, Electrical insulating materials – Determination of the effects of ionizing radiation
– Part 4: Classification system for service in radiation environments
– Determination of tensile stress-strain
ISO 37, Rubber, vulcanized or thermoplastic
properties

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SIST EN 60544-2:2012
60544-2 © IEC:2012 – 9 –
ISO 48, Rubber, vulcanized or thermoplastic – Determination of hardness (hardness between
10 IRHD and 100 IRHD)
ISO 178, Plastics – Determination of flexural properties
ISO 179 (all parts), Plastics – Determination of Charpy impact properties
ISO 527 (all parts), Plastics – Determination of tensile properties
ISO 815 (all parts), Rubber, vulcanized or thermoplastic – Determination of compression set
ISO 868, Plastics and ebonite – Determination of indentation hardness by means of a
durometer (Shore hardness)
3 Irradiation
3.1 Type of radiation and dosimetry
The following types of radiation are covered by the standard:
– X- and γ-rays;
– electrons;
– protons;
– neutrons;
– combined γ-rays and neutrons ("reactor" radiation).
In general, the radiation effects may be different for different types of radiation. However, in
many practical applications, it has been found that with analogous experimental conditions,
equal absorbed dose and equal linear energy transfer, the changes in properties will be only
slightly dependent on the type of radiation [15-17]. Thus, the preferred type of radiation
should be one for which the absorbed dose measurement is simple and precise, for example
60
Co γ-rays or fast electrons. For a comparison of the effect of reactor radiation with γ-rays or
fast electrons, specimens with the same chemical composition can be irradiated with these
various types of radiation and the radiation-induced changes can be compared.
Radiation-induced changes are related to the absorbed radiation energy, expressed by the
absorbed dose. Recommended methods of dosimetry are listed in IEC 60544-1. The
definitions of absorbed dose, absorbed dose rate and the units are also given in IEC 60544-1
and repeated here for convenience.
The absorbed dose, D, is the quotient of dε by dm, where dε is the mean energy imparted by
ionizing radiation to the matter in a volume element and dm is the mass of the matter in that
volume element.
dε
D=
dm
The absorbed dose rate, D, is the increment of the absorbed dose dD in the time interval dt.
dD

D=
dt
Units
The SI unit of absorbed dose is the gray (Gy);

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SIST EN 60544-2:2012
– 10 – 60544-2 © IEC:2012
2
1 Gy = 1 J/kg (= 10 rad).
Usual multiples for higher doses are the kilogray (kGy) or megagray (MGy).
The SI unit of absorbed dose rate is the gray per second;
2
1 Gy/s = 1 W/kg (=10 rad/s = 0,36 Mrad/h).
3.2 Irradiation conditions
The irradiation conditions which must be established are as follows:
– type and energy of the radiation;
– absorbed dose;
– absorbed dose rate;
– surrounding medium;
– temperature;
– mechanical, electrical and other stresses;
– sample thickness.
It is preferable to use γ-rays, X-rays or electrons for the irradiation (see 3.1). Their energy
should be so chosen that the homogeneity of the absorbed dose in the sample is within ±15 %.
3.3 Sample preparation
The test specimens shall be carefully prepared in accordance with the appropriate IEC and
ISO standards, because a variation in test results may be due to differences in the quality of
test specimens.
Because the effect of radiation can depend on the dimensions of the specimens, these shall
be uniform for all comparison studies. It is preferable to irradiate the test specimens in the
geometry needed for subseque
...