EN 60544-1:2013

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

IEC 60544-1:2013 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, gamma-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. 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.

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: 12-Sep-2013
• Withdrawal Date: 31-Jul-2016
• ICS: 17.240 - Radiation measurements
• ICS: 29.035.01 - Insulating materials in general
• Technical Committee: CLC/SR 112 - Evaluation and qualification of electrical insulating materials and systems (to be defined)
• Drafting Committee: IEC/TC 112 - IEC_TC_112
• Current Stage: 6060 - Document made available - Publishing
• Start Date: 13-Sep-2013
• Completion Date: 13-Sep-2013
• Ref Project: SIST EN 60544-1:2014 - Electrical insulating materials - Determination of the effects of ionizing radiation - Part 1: Radiation interaction and dosimetry

Relations

• Replaces: EN 60544-1:1994 - Electrical insulating materials - Determination of the effects of ionizing radiation - Part 1: Radiation interaction and dosimetry
• Effective Date: 28-Jan-2023

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN 60544-1:2014
01-maj-2014
1DGRPHãþD
SIST EN 60544-1:1998

(OHNWURL]RODFLMVNLPDWHULDOL8JRWDYOMDQMHXþLQNRYLRQL]DFLMVNHJDVHYDQMDGHO

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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

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

Table A.1 – Electron mass collision stopping powers, S/ρ (MeV cm /g) ................................. 23

Table A.2 – Photon mass energy absorption coefficients, µ /ρ (cm /g) .............................. 24

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SIST EN 60544-1:2014
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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

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

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:
—————————
References in square brackets refer to the Bibliography.
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SIST EN 60544-1:2014
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X = (1)

The SI unit of exposure is the coulomb (C) per kilogram: C/kg. The old unit is the roentgen R:

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

quotient obtained by dividing dQ by dA, where dQ is the electron charge impinging during the

time t on the area dA:
Q = (2)
d A
3.3
electron current density

quotient obtained by dividing dQ′ by dt, where dQ′ is the electron charge fluence during the

time interval dt:
dQ′ d Q
j = = (3)
dt d A dt
3.4
absorbed dose

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:
D = (4)
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

quotient obtained by dividing dD by dt, where dD is the increment of absorbed dose in the

time interval dt:
D = (5)
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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
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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

 

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)

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

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
...