IEC TR 61577-5:2019

Radiation protection instrumentation - Radon and radon decay product measuring instruments - Part 5: General properties of radon and radon decay products and their measurement methods

IEC TR 61577-5:2019 provides basic data and technical information in order to support the design of instruments and their practical application for the measurement. The document covers 222Rn as well as 220Rn and the short-lived decay products of both. It is an accompanying document for the application of the technical standards series IEC 61577, and provides physical and technical fundamentals of the measurements methods.

General Information

• Status: Published
• Publication Date: 15-Jul-2019
• ICS: 01 - GENERALITIES. TERMINOLOGY. STANDARDIZATION. DOCUMENTATION
• ICS: 13.280 - Radiation protection
• Technical Committee: SC 45B - Radiation protection instrumentation
• Drafting Committee: WG 10 - TC 45/SC 45B/WG 10
• Current Stage: PPUB - Publication issued
• Start Date: 02-Aug-2019
• Completion Date: 16-Jul-2019

Standards Content (Sample)

IEC TR 61577-5 ®
Edition 1.0 2019-07
TECHNICAL
REPORT
colour
inside
Radiation protection instrumentation – Radon and radon decay product
measuring instruments –
Part 5: General properties of radon and radon decay products and their
measurement methods
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
your local IEC member National Committee for further information.

IEC Central Office Tel.: [phone]
3, rue de Varembé [e-mail]
CH-1211 Geneva 20 www.iec.ch
Switzerland
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigendum or an amendment might have been published.

IEC publications search - webstore.iec.ch/advsearchform Electropedia - www.electropedia.org
The advanced search enables to find IEC publications by a The world's leading online dictionary on electrotechnology,
variety of criteria (reference number, text, technical containing more than 22 000 terminological entries in English
committee,…). It also gives information on projects, replaced and French, with equivalent terms in 16 additional languages.
and withdrawn publications. Also known as the International Electrotechnical Vocabulary

(IEV) online.
IEC Just Published - webstore.iec.ch/justpublished
Stay up to date on all new IEC publications. Just Published IEC Glossary - std.iec.ch/glossary
details all new publications released. Available online and 67 000 electrotechnical terminology entries in English and
once a month by email. French extracted from the Terms and Definitions clause of
IEC publications issued since 2002. Some entries have been
IEC Customer Service Centre - webstore.iec.ch/csc collected from earlier publications of IEC TC 37, 77, 86 and
If you wish to give us your feedback on this publication or CISPR.

need further assistance, please contact the Customer Service

Centre: [e-mail].
IEC TR 61577-5 ®
Edition 1.0 2019-07
TECHNICAL
REPORT
colour
inside
Radiation protection instrumentation – Radon and radon decay product

measuring instruments –
Part 5: General properties of radon and radon decay products and their

measurement methods
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 13.280 ISBN 978-2-8322-7123-0

– 2 – IEC TR 61577-5:2019  IEC:2019
CONTENTS
FOREWORD . 5
1 Scope . 7
2 Normative references . 7
3 Symbols, quantities and units . 8
3.1 Symbols . 8
3.2 Quantities and units . 9
4 Radon in the environment . 9
4.1 Origin, genesis and decay . 9
4.2 Radon in the rocks and soils and its transport towards the atmosphere . 10
4.3 Radon concentration in the outdoor air. 11
4.4 Radon concentration in houses and at workplaces . 11
5 Radon decay products in the atmosphere . 12
5.1 Physical processes of decay products in gaseous media . 12
5.2 Aerosol characteristics and ventilation . 13
6 Physical and chemical properties of radon and radon decay products . 14
6.1 Physical and chemical properties . 14
6.2 Solubility of radon in liquids . 14
6.3 Radiological properties and radioactive equilibrium . 15
6.4 Interaction of alpha particles with matter and energy deposition . 17
222 220
7 Measurement of Rn and Rn and their decay products . 18
7.1 Relevant measurement quantities and units . 18
7.1.1 Activity concentration (C) . 18
7.1.2 Equilibrium equivalent activity concentration (EEC, C ) . 18
eq
7.1.3 Equilibrium factor (F) . 19
7.1.4 Exposure to radon (P ) . 19
Rn
7.1.5 Potential alpha energy (ε ) . 20
p
7.1.6 Potential alpha energy concentration (C ) . 20
p
7.1.7 Potential alpha energy exposure (P ) . 22
p
7.1.8 The unattached and attached fraction of potential alpha energy
concentration . 22
7.2 Instruments measuring airborne radon activity concentration . 22
7.3 Measurement of radon decay products . 23
7.3.1 General overview of instruments . 23
7.3.2 Sampling of the unattached radon decay products . 24
7.3.3 Counting methods for the measurement of the activity concentrations
and the potential alpha-energy concentration . 25
8 Quality assurance . 30
8.1 Definition and purpose . 30
8.2 Quality control . 31
8.3 Validation and traceability of measurements . 31
8.3.1 Validation of methods . 31
8.3.2 Type test of radon instruments . 31
8.3.3 Interlaboratory comparison . 31
8.3.4 Measurement traceability and calibration . 32
9 Determination of the measurement uncertainty, detection threshold, detection limit . 32
9.1 General . 32

9.2 Procedure for the determination . 33
Annex A (informative) Tables and Figures . 35
Annex B (informative) Radioactive decay formulae . 40
B.1 General . 40
B.2 Symbols . 40
B.3 Preliminary considerations and assumptions . 40
B.4 Build-up of filter activity during sampling . 41
B.5 Decay of the filter activity after cessation of sampling . 43
B.6 Number of alpha disintegrations registered after sampling . 44
Annex C (informative) Uncertainty analysis for the method of multiple successive
countings to determine the activity concentrations of radon and thoron decay products . 46
C.1 Symbols . 46
C.2 Uncertainties of the parameter of the model function . 46
C.3 Decision threshold . 50
C.4 Detection limit . 51
C.5 Confidence limits . 51
C.6 Best estimate and its uncertainty . 52
Bibliography . 53

st
Figure 1 – Diurnal variations of the radon activity concentration in the cellar, 1 and
nd
2 floor of a detached house measured over 12 days . 12
Figure 2 – Decay of Rn after injection of 1 000 Bq at the start time and generation
of decay products . 16
Figure 3 – Decay of Rn (Thoron) after injection of 1 000 Bq at the start time and
generation of decay products . 16
Figure 4 – Activity build-up of Rn and its decay products for a continuous supply of
Rn with a rate of 1 Bq/s (in the absence of initial activities) . 16
Figure 5 – Activity build-up of Rn (Thoron) and its decay products for a continuous
supply of Rn with a rate of 1 Bq/s (in the absence of initial activities) . 16
Figure 6 – Total stopping power of alpha particles penetrating different materials, the
graphs use data from [38] . 17
Figure 7 – Contributions of the deposition processes to the total efficiency (calculated
exemplarily for a wire screen) . 24
Figure 8 – Variation of deposition efficiency of a wire screen in dependence on air flow
velocity (calculated exemplarily for a wire screen) . 24
Figure 9 – Measurement error of the method of MARKOV given in percent for different
ratios of decay products in the air sampled . 27
Figure 10 – Method of multiple successive countings . 28
Figure A.1 – Sampling and measurement procedures commonly used for radon
instruments . 35
Figure A.2 – Sampling and measurement procedures commonly used for radon
progeny instruments . 35
Figure B.1 – Scheme for sampling and counting . 44

Table 1 – Coefficients for the calculation of the equilibrium equivalent concentration

from measured activity concentrations of radon progeny . 19
Table 2 – Potential alpha energy per atom for Rn progeny including standard
uncertainty . 21

– 4 – IEC TR 61577-5:2019  IEC:2019
Table 3 – Potential alpha energy per atom for Rn progeny including standard
uncertainty . 21
Table 4 – Time scheme for the method of Thomas [57] . 26
Table 5 – Time scheme for the method of MARKOV [63] . 27
Table A.1 – Physical and chemical characteristics [29] . 36
226 222 222
Table A.2 – Ra, Rn and radionuclides of the Rn decay chain [37] . 36
224 220 220
Table A.3 – Ra, Rn and radionuclides of the Rn decay chain [37] . 37
Table A.4 – CSDA-Range of alpha particles emitted by Radon-222 and Radon-220
decay products in different materials [38] .
...