SIST EN 60544-1:2014

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

This part of IEC 60544 deals broadly with the aspects to be considered in evaluating the effects of ionizing radiation on all types of organic insulating materials. It also provides, for Xrays, -rays, and electrons, a guide to - dosimetry terminology, - methods for dose measurements, - testing carried out at irradiation facilities, - evaluation and testing of material characteristics and properties, - documenting the irradiation process. Dosimetry that might be carried out at locations of use of the material is not described in this standard.

Elektroisolierstoffe - Bestimmung der Auswirkungen ionisierender Strahlung - Teil 1: Einfluss der Strahlenwirkung und Dosimetrie

Matériaux isolants électriques - Détermination des effets des rayonnements ionisants - Partie 1: Interaction des rayonnements et dosimétrie

La CEI 60544-1:2013 traite de manière générale des aspects à envisager lors de l'évaluation des effets des rayonnements ionisants sur tous les types de matériaux isolants organiques. Elle fournit également pour les rayons X, les rayonnement gamma et les électrons, un guide de terminologie en dosimétrie, des méthodes de mesure des doses, des essais réalisés au niveau des dispositifs d'irradiation, relatif à l'évaluation et aux essais des caractéristiques et propriétés des matériaux, de documentation du phénomène d'irradiation. Cette édition inclut les changements techniques majeurs suivants par rapport à l'édition précédente:  a) des avancées récentes au niveau des méthodes de simulation de l'interaction des rayonnements avec des types de matière différents permettent de prédire le profil de dépôt d'énergie dans la matière et de concevoir la procédure d'irradiation;  b) de nombreux nouveaux systèmes de dosimétrie sont actuellement disponibles.

Elektroizolacijski materiali - Ugotavljanje učinkov ionizacijskega sevanja - 1. del: Medsebojni vplivi sevanja in dozimetrija (IEC 60544-1:2013)

Ta del standarda IEC 60544 na splošno obravnava vidike, ki jih je treba upoštevati pri ocenjevanju učinkov ionizirajočega sevanja vseh vrst bioloških izolacijskih materialov. Za rentgenske žarke, sevanje in elektrone vsebuje tudi vodnik za – dozimetrijsko terminologijo, – metode merjenja odmerkov, – testiranja, opravljena v objektih za obsevanje, – vrednotenje in preskušanje značilnosti in lastnosti materiala, – dokumentiranje postopka obsevanja. Dozimetrija, ki morda poteka na mestih uporabe materiala, ni opisana v tem standardu.

General Information

• Status: Published
• Publication Date: 09-Apr-2014
• ICS: 17.240 - Radiation measurements
• 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-Mar-2014
• Due Date: 30-May-2014
• Completion Date: 10-Apr-2014
• Ref Project: EN 60544-1:2013 - Electrical insulating materials - Determination of the effects of ionizing radiation - Part 1: Radiation interaction and dosimetry

Relations

• Replaces: SIST EN 60544-1:1998 - Electrical insulating materials - Determination of the effects of ionizing radiation -- Part 1: Radiation interaction and dosimetry
• Effective Date: 24-Jul-2012
• Revised: SIST EN 60544-1:1998 - Electrical insulating materials - Determination of the effects of ionizing radiation -- Part 1: Radiation interaction and dosimetry
• Effective Date: 06-May-2014
• Replaces: SIST EN 60544-1:1998 - Electrical insulating materials - Determination of the effects of ionizing radiation -- Part 1: Radiation interaction and dosimetry
• Effective Date: 28-Jan-2023
• Replaces: SIST EN 60544-1:1998 - Electrical insulating materials - Determination of the effects of ionizing radiation -- Part 1: Radiation interaction and dosimetry
• Effective Date: 07-Jun-2022

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN 60544-1:2014
01-maj-2014
1DGRPHãþD
SIST EN 60544-1:1998
(OHNWURL]RODFLMVNLPDWHULDOL8JRWDYOMDQMHXþLQNRYLRQL]DFLMVNHJDVHYDQMDGHO
0HGVHERMQLYSOLYLVHYDQMDLQGR]LPHWULMD,(&
Electrical insulating materials - Determination of the effects of ionizing radiation - Part 1:
Radiation interaction and dosimetry
Matériaux isolants électriques - Détermination des effets des rayonnements ionisants -
Partie 1: Interaction des rayonnements et dosimétrie
Ta slovenski standard je istoveten z: EN 60544-1:2013
ICS:
17.240 Merjenje sevanja Radiation measurements
29.035.01 Izolacijski materiali na Insulating materials in
splošno general
SIST EN 60544-1:2014 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 60544-1:2014

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SIST EN 60544-1:2014

EUROPEAN STANDARD
EN 60544-1

NORME EUROPÉENNE
September 2013
EUROPÄISCHE NORM

ICS 17.240; 29.035.01 Supersedes EN 60544-1:1994


English version


Electrical insulating materials -
Determination of the effects of ionizing radiation -
Part 1: Radiation interaction and dosimetry
(IEC 60544-1:2013)


Matériaux isolants électriques -  Elektroisolierstoffe - Bestimmung der
Détermination des effets des Wirkung ionisierender Strahlung -
rayonnements ionisants - Teil 1: Einfluss der Strahlenwirkung und
Partie 1: Interaction des rayonnements et Dosimetrie
dosimétrie (IEC 60544-1:2013)
(CEI 60544-1:2013)





This European Standard was approved by CENELEC on 2013-08-01. 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

CEN-CENELEC Management Centre: Avenue Marnix 17, B - 1000 Brussels


© 2013 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 60544-1:2013 E

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SIST EN 60544-1:2014
EN 60544-1:2013 - 2 -

Foreword
The text of document 112/254/FDIS, future edition 3 of IEC 60544-1, 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 60544-1:2013.
The following dates are fixed:
(dop) 2014-05-01
• 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) 2016-08-01
standards conflicting with the

document have to be withdrawn

This document supersedes EN 60544-1:1994.
EN 60544-1:2013 includes the following significant technical changes with respect to EN 60544-1:1994:
a) recent advances in simulation methods of radiation interaction with different matter enables the
prediction of the energy-deposition profile in matter and design the irradiation procedure;
b) many new dosimetry systems have become available.
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 60544-1:2013 was approved by CENELEC as a European
Standard without any modification.
In the official version, for Bibliography, the following note has to be added for the standard indicated:
ISO 11137 series NOTE  Harmonised in EN ISO 11137 series.

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SIST EN 60544-1:2014
- 3 - EN 60544-1:2013
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 60544-2 - Electrical insulating materials - Determination EN 60544-2 -
of the effects of ionizing radiation on insulating
materials -
Part 2: Procedures for irradiation and test


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

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SIST EN 60544-1:2014

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SIST EN 60544-1:2014



IEC 60544-1

®


Edition 3.0 2013-06




INTERNATIONAL



STANDARD




NORME



INTERNATIONALE











Electrical insulating materials – Determination of the effects of ionizing

radiation –

Part 1: Radiation interaction and dosimetry




Matériaux isolants électriques – Détermination des effets des rayonnements

ionisants –


Partie 1: Interaction des rayonnements et dosimétrie













INTERNATIONAL

ELECTROTECHNICAL

COMMISSION


COMMISSION

ELECTROTECHNIQUE

PRICE CODE
INTERNATIONALE

CODE PRIX V


ICS 17.240; 29.035.01 ISBN 978-2-83220-894-6



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 60544-1:2014
– 2 – 60544-1 © IEC:2013
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 7
4 Radiation-induced changes and their evaluation . 9
4.1 General . 9
4.2 Permanent changes . 9
4.3 Environmental conditions and material geometry . 9
4.4 Post-irradiation effects . 9
4.5 Temporary effects . 9
5 Facilities for irradiation of material samples for evaluation of properties . 10
5.1 General . 10
5.2 Gamma-ray irradiators . 10
5.3 Electron-beam irradiators . 10
5.4 X-ray (Bremsstrahlung) irradiators . 11
6 Dosimetry methods . 11
6.1 General . 11
6.2 Absolute dosimetry methods . 12
6.2.1 Gamma-rays . 12
6.2.2 Electron beams . 12
6.3 Dosimetry systems . 12
6.3.1 Reference standard dosimetry systems . 12
6.3.2 Routine dosimetry systems . 13
6.3.3 Measurement uncertainty . 14
6.3.4 Dosimeter calibration . 15
6.3.5 Dosimeter selection . 15
7 Characterization of irradiation facilities . 16
8 Dose mapping of samples for test . 16
8.1 Charged particle equilibrium . 16
8.2 Depth-dose distribution (limitations) . 16
9 Monitoring of the irradiation . 17
Annex A (informative) Radiation chemical aspects in interaction and dosimetry . 18
Bibliography . 31

Figure A.1 – Absorbed dose as a function of thickness . 19
Figure A.2 – Absorber thickness for charged-particle equilibrium as a function of
23 -3
energy for a material with an electron density of 3,3 × 10 cm (water). 20
3
Figure A.3 – Thickness of water (1 g/cm ) as a function of photon energy for a given
attenuation of unidirectional X-ray or γ-ray radiation . 21
Figure A.4 – Typical depth-dose distribution in a homogeneous material obtained with
electron accelerators for radiation processing . 25
Figure A.5 – Example of calculated results of energy deposition function, I(z′), for a
slab layer of polyethylene exposed to 1 MeV electron . 25
Figure A.6 – Example of calculated results of energy deposition function, I(z′), for
typical organic insulators exposed to 1 MeV electron . 26

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SIST EN 60544-1:2014
60544-1 © IEC:2013 – 3 –
Figure A.7 – Two methods of arranging the irradiation samples in order to take into
account the typical depth-dose distributions . 27
Figure A.8 – Methods of arranging the irradiation samples for measuring electron
depth-dose distributions with a stack of slab insulating materials and wedge-shape
insulating materials . 28
Figure A.9 – Scheme of radiation effects of polymers. 29

Table 1 – Examples of reference standard dosimeters . 13
Table 2 – Examples of routine dosimeter systems . 14
2
Table A.1 – Electron mass collision stopping powers, S/ρ (MeV cm /g) . 23
2
Table A.2 – Photon mass energy absorption coefficients, µ /ρ (cm /g) . 24
en

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SIST EN 60544-1:2014
– 4 – 60544-1 © IEC:2013
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________

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

Part 1: Radiation interaction and dosimetry

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 60544-1 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 1994 and constitutes a
technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) recent advances in simulation methods of radiation interaction with different matter
enables the prediction of the energy-deposition profile in matter and design the irradiation
procedure;
b) many new dosimetry systems have become available.

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SIST EN 60544-1:2014
60544-1 © IEC:2013 – 5 –
The text of this standard is based on the following documents:
FDIS Report on voting
112/254/FDIS 112/262/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 in the IEC 60544 series, published under the general title Electrical insulating
materials – Determination of the effects of ionizing 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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SIST EN 60544-1:2014
– 6 – 60544-1 © IEC:2013
INTRODUCTION
The establishment of suitable criteria for the evaluation of the radiation resistance of
insulating materials is very complex, since such criteria depend upon the conditions under
which the materials are used. For instance, if an insulated cable is flexed during a refuelling
operation in a reactor, the service life will be that time during which the cable receives a
radiation dose sufficient to reduce to a specified value one or more of the relevant mechanical
properties. Temperature of operation, composition of the surrounding atmosphere and the
time interval during which the total dose is received (dose rate or flux) are important factors
which also determine the rate and mechanisms of chemical changes. In some applications,
temporary changes may be the limiting factor.
Given this, it becomes necessary to define the radiation fields in which materials are exposed
and the radiation dose subsequently absorbed by the material. It is also necessary to
establish procedures for testing the mechanical and electrical properties of materials which
will define the radiation degradation and link those properties with application requirements in
order to provide an appropriate classification system.

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SIST EN 60544-1:2014
60544-1 © IEC:2013 – 7 –
ELECTRICAL INSULATING MATERIALS –
DETERMINATION OF THE EFFECTS OF IONIZING RADIATION –

Part 1: Radiation interaction and dosimetry



1 Scope
This part of IEC 60544 deals broadly with the aspects to be considered in evaluating the
effects of ionizing radiation on all types of organic insulating materials. It also provides, for X-
rays, γ-rays, and electrons, a guide to
– dosimetry terminology,
– methods for dose measurements,
– testing carried out at irradiation facilities,
– evaluation and testing of material characteristics and properties,
– documenting the irradiation process.
Dosimetry that might be carried out at locations of use of the material is not described in this
standard.
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 60544-2, Electrical insulating materials – Determination of the effects of ionizing radiation
on insulating materials – Part 2: Procedures for irradiation and test
IEC 60544-4, Electrical insulating materials – Determination of the effects of ionizing radiation
– Part 4: Classification system for service in radiation environments
3 Terms and definitions
1
For the purposes of this document, the terms and definitions in ICRU Report 33 [1] . as well
as the following definitions apply.
3.1
exposure
X
measure of an electromagnetic radiation field (X- or γ-radiation) to which a material is
exposed
Note 1 to entry: The exposure is the quotient obtained by dividing dQ by dm, where dQ is the absolute value of
the total charge of the ions of one sign produced in the air when all of the electrons (and positrons) liberated by
photons in air of mass dm are completely stopped in air:
—————————
1
 References in square brackets refer to the Bibliography.

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SIST EN 60544-1:2014
– 8 – 60544-1 © IEC:2013
dQ
X = (1)
dm
The SI unit of exposure is the coulomb (C) per kilogram: C/kg. The old unit is the roentgen R:
-4
1 R = 2,58 × 10 C/kg.
The exposure thus describes the effect of an electromagnetic field on matter in terms of the ionization that the
radiation produces in a standard reference material, air.
3.2
electron charge fluence
Q′
quotient obtained by dividing dQ by dA, where dQ is the electron charge impinging during the
time t on the area dA:
dQ
Q = (2)
′
d A
3.3
electron current density
j
quotient obtained by dividing dQ′ by dt, where dQ′ is the electron charge fluence during the
time interval dt:
2
dQ′ d Q
j = = (3)
dt d A dt
3.4
absorbed dose
D
measure of the energy imparted to the irradiated material, regardless of the nature of the
radiation field
Note 1 to entry: The absorbed dose D is the quotient obtained by dividing d ε by dm where d ε is the mean
energy imparted by ionizing radiation to matter of mass dm:
dε
D = (4)
dm
The SI unit is the gray (Gy). The old unit is the rad:
-1 2
1 Gy = 1 J × kg (= 10 rad).
Since this definition does not specify the absorbing material, the gray can be used only with reference to a specific
material. The absorbed dose is determined in part by the composition of the irradiated material. When exposed to
the same radiation field, therefore, different materials usually receive different absorbed doses.
Note 2 to entry: For purposes of dosimetry, it has been found convenient to specify dose in terms of dose to water.
The dose to other materials can be found by applying cavity theory.
3.5
absorbed dose rate

D
quotient obtained by dividing dD by dt, where dD is the increment of absorbed dose in the
time interval dt:
dD

D = (5)
dt

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SIST EN 60544-1:2014
60544-1 © IEC:2013 – 9 –
The SI unit of absorbed dose rate is the gray per second:
-1 -1 2 -1 -1
1 Gy × s = 1 W × kg (= 10 rad × s = 0,36 Mrad × h )
4 Radiation-induced changes and their evaluation
4.1 General
Although the various types of radiation interact with matter in different ways, the primary
process is the production of ions and electrically excited states of molecules which, in turn,
may lead to the formation of free radicals. The technique to detect ions, excited states and
radicals (short-lived intermediate species) are briefly described in Clause A.4. Radiation-
generated mobile electrons, which become trapped at sites of low potential energy, are also
produced. The first phenomenon leads to permanent chemical, mechanical, and electrical
changes of the material; the second results in temporary electrical changes in performance [2].
4.2 Permanent changes
In polymeric materials, the formation of free radicals during irradiation leads to scission and
cross-linking processes that modify the chemical structure of the insulation, generally leading
to deterioration of the mechanical properties. This mechanical deterioration frequently gives
rise to significant electrical property changes. However, important electrical property changes
sometimes occur before mechanical degradation becomes serious. For example, a change in
dissipation factor or in permittivity might become serious for the reliable functioning of a
resonant circuit. The extent of scission and cross-linking processes depends on the absorbed
dose, the absorbed dose rate, the material geometry and the environmental conditions
present during the irradiation. Because the free radicals sometimes decay slowly, there may
also be post-irradiation effects.
4.3 Environmental conditions and material geometry
Environmental conditions and test specimen geometry 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, the irradiation time (flux and dose rate) has also been
demonstrated to be a very important experimental parameter because of oxygen diffusion
effects and hydroperoxide breakdown rate constants. Both factors are time dependent. The
conditions that influence oxygen diffusion and equilibrium concentrations in the polymer shall
be controlled. These include: temperature, oxygen pressure, material geometry and the time
during which the dose is applied.
If the effect of simultaneous stresses, e.g. radiation at high temperature, is simulated by
sequential stressing, other results are to be expected. Further, there can be differences in
results if the sample is first irradiated and then heat aged or vice versa.
4.4 Post-irradiation effects
In organic polymers, there may be post-irradiation effects due to the gradual decay of various
reactants, such as residual free radicals. Due allowance shall be made for this type of
behaviour in any evaluation procedure. The tests shall be made at recorded intervals after
irradiation, maintaining specimen storage in a standard laboratory atmosphere. The reaction
of oxygen with residual free radicals can cause further degradation.
4.5 Temporary effects
4.5.1 Performing measurements during irradiation is not within the scope of this part
of IEC 60544. Despite this, some basic aspects will be discussed briefly. The temporary
effects appear primarily as changes in electrical properties such as induced conductivity, both
during and for some time after irradiation. Hence, measurement of the induced conductivity

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SIST EN 60544-1:2014
– 10 – 60544-1 © IEC:2013
could be used as an evaluation property to determine the temporary radiation effects. These
effects are primarily dose-rate dependent.
4.5.2 Experience has shown that the induced conductivity is usually not quite proportional
 
α
to the absorbed dose rate D, but varies as D , where α is smaller than unity. Hence, the
radiation sensitivity is described by the relation:
 α
σ = kD (6)
i
To determine k and α, at least two measurements are needed. A further complication
comes from the fact that k and α also depend on the integrated dose absorbed by the sample.
The measurement of the induced conductivity is actually quite delicate, since photoelectrons
and Compton electrons in the electrode materials will tend to perturb the intrinsic induced
current of the specimen. Ionic currents through the ionized atmosphere will also introduce
errors in the measurement if they are not eliminated. Experimental procedures eliminating
most of the disturbing effects, while remaining relatively simple, shall be defined.
NOTE It is convenient to use a simple figure such as the induced conductivity σ or σ /σ , its ratio to the dark
i i o
conductivity σ measured in the same experimental conditions, per unit dose rate to characterize the sensitivity of
o
the materials to temporary effects.
5 Facilities for irradiation of material samples for evaluation of properties
5.1 General
Irradiation of material samples for evaluation of properties shall be performed at irradiation
facilities that have undergone installation qualification, operational qualification and
performance qualification, see e.g. ISO 11137 [3].
Three principal types of radiation sources are used:
60 137
• gamma radiation from radionuclides such as Co (1,25 MeV) and Cs (0,66 MeV);
• electrons from accelerators;
• X-rays generated from accelerated electrons.
The design and properties of an irradiation facility have implications for absorbed dose
distribution in the samples and att
...