1、BSI Standards Publication BS ISO 8769:2016 Reference sources Calibration of surface contamination monitors Alpha-, beta- and photon emittersBS ISO 8769:2016 BRITISH STANDARD National foreword This British Standard is the UK implementation of ISO 8769:2016. It supersedes BS ISO 8769:2010 which is wit
2、hdrawn. The UK participation in its preparation was entrusted to Technical Committee NCE/2, Radiation protection and measurement. A list of organizations represented on this committee can be obtained on request to its secretary. This publication does not purport to include all the necessary provisio
3、ns of a contract. Users are responsible for its correct application. The British Standards Institution 2016. Published by BSI Standards Limited 2016 ISBN 978 0 580 83093 8 ICS 17.240 Compliance with a British Standard cannot confer immunity from legal obligations. This British Standard was published
4、 under the authority of the Standards Policy and Strategy Committee on 31 January 2016. Amendments/corrigenda issued since publication Date T e x t a f f e c t e dBS ISO 8769:2016 ISO 2016 Reference sources Calibration of surface contamination monitors Alpha-, beta- and photon emitters Sources de rf
5、rence talonnage des contrleurs de contamination de surface metteurs alpha, bta et photoniques INTERNATIONAL STANDARD ISO 8769 Third edition 2016-01-15 Reference number ISO 8769:2016(E)BS ISO 8769:2016ISO 8769:2016(E)ii ISO 2016 All rights reserved COPYRIGHT PROTECTED DOCUMENT ISO 2016, Published in
6、Switzerland All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can
7、be requested from either ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Ch. de Blandonnet 8 CP 401 CH-1214 Vernier, Geneva, Switzerland Tel. +41 22 749 01 11 Fax +41 22 749 09 47 copyrightiso.org www.iso.orgBS ISO 8769:2016ISO 8769:2016(E)Foreword
8、iv Introduction v 1 Scope . 1 2 Normative references 1 3 T erms and definitions . 1 4 Traceability of reference sources 2 5 Specification of standar d sour c es . 3 5.1 General . 3 5.2 Class 1 reference sources . 4 5.2.1 General requirements 4 5.2.2 Activity and surface emission rate . 5 5.2.3 Unifo
9、rmity . 5 5.2.4 Radionuclides . 6 5.3 Class 2 reference sources . 7 5.3.1 General requirements 7 5.3.2 Activity and surface emission rate . 8 5.3.3 Uniformity . 8 5.3.4 Radionuclides . 8 5.4 Working sources 8 5.4.1 General requirements 8 5.4.2 Activity and surface emission rate . 9 5.4.3 Uniformity
10、. 9 5.4.4 Radionuclides . 9 6 Reference transfer instruments . 9 6.1 Reference transfer instrument for alpha-sources and beta-sources 9 6.2 Reference transfer instrument for photon sources . 9 6.3 Calibration 9 Annex A (informative) Particular considerations for reference sources emitting electrons
11、of energy less than 0,15 MeV and photons of energy less than 1,5 MeV . .11 Bibliography .13 ISO 2016 All rights reserved iii Contents PageBS ISO 8769:2016ISO 8769:2016(E) Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO mem
12、ber bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmen
13、tal and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. The procedures used to develop this document and those intended for its further maintenance
14、 are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives). Attention
15、is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any patent rights identified during the development of the document will be in the Introduction and/
16、or on the ISO list of patent declarations received (see www.iso.org/patents). Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement. For an explanation on the meaning of ISO specific terms and expressions related to conformity a
17、ssessment, as well as information about ISOs adherence to the WTO principles in the Technical Barriers to Trade (TBT) see the following URL: Foreword - Supplementary information. The committee responsible for this document is ISO/TC 85, Nuclear energy, Subcommittee SC 2, Radiological protection. Thi
18、s third edition cancels and replaces the second edition (ISO 8769:2010), which has been technically revised.iv ISO 2016 All rights reservedBS ISO 8769:2016ISO 8769:2016(E) Introduction Radioactive contamination of surfaces can result from spilling, splashing, or leakage from unsealed sources, or bre
19、akage or loss of integrity of sealed sources and can give rise to the following health hazards: a) external exposure to parts of the body in proximity to the contaminated surface; b) internal exposure through incorporation of radioactive material released from the surface. The need for effective mon
20、itoring of surface contamination has long been recognized, see Reference 1. Surface contamination is quantified in terms of activity per unit area, the quantity which is normally used to specify “derived limits”, i.e. maximum limits of surface contamination. These limits are based on radiological pr
21、otection considerations and have been derived from the dose equivalent or intake limits recommended by the International Commission on Radiological Protection (ICRP), see References 2 and 3. Derived limits are incorporated into numerous national and international regulatory documents which relate sp
22、ecifically to surface contamination monitoring. The requirement for this International Standard originated from the need for standard calibration sources in those International Standards dealing with the calibration of surface contamination monitors. While regulatory documents refer to surface conta
23、mination in terms of activity per unit area, the response of monitoring instruments is related directly to the radiation emitted from the surface rather than to the activity contained upon or within the surface. Due to variations in the absorptive and scattering properties of real surfaces, it canno
24、t be assumed, in general, that there is a simple, known relationship between surface emission rate and activity. Thus, there emerges a clear need for calibration sources that are specified primarily in terms of surface emission rate, as well as activity. The manner in which these sources are used an
25、d the associated calibration protocols vary from country to country 4 . Calibration of an instrument in terms of activity for the types of surfaces that are usually encountered in monitoring situations depends on the following considerations: mixture and ratios of radionuclides being monitored; thei
26、r types and abundances of emissions; nature of the surface; depths and distribution profiles within the surface; spectral attenuation dependence of the instrument entrance window; distance between the instrument entrance window and the surface. The derivation of appropriate calibration factors in te
27、rms of activity is therefore a highly complex process which is outside the scope of this International Standard. Appropriate guidance on this process is addressed in ISO 7503 series 567 . However, some estimate of the activity of the calibration source is required for general radiological safety pur
28、poses such as handling, leak testing, shielding, packaging, and transport. This is a generic issue for all radioactive sources regardless of their intended use and is not therefore addressed specifically in this International Standard. Traceability of calibration sources to International Standards o
29、r national standards is established by a system of reference transfer instruments. ISO 2016 All rights reserved vBS ISO 8769:2016BS ISO 8769:2016Reference sources Calibration of surface contamination monitors Alpha-, beta- and photon emitters 1 Scope This International Standard specifies the charact
30、eristics of reference sources of radioactive surface contamination, traceable to national measurement standards, for the calibration of surface contamination monitors. This International Standard relates to alpha-emitters, beta-emitters, and photon emitters of maximum photon energy not greater than
31、1,5 MeV. It does not describe the procedures involved in the use of these reference sources for the calibration of surface contamination monitors. Such procedures are specified in IEC 60325 8 , IEC 62363 9 , and other documents. NOTE Since some of the proposed photon sources include filters, the pho
32、ton sources are to be regarded as sources of photons of a particular energy range and not as sources of a particular radionuclide. For example, a 241 Am source with the recommended filtration does not emit from the surface the alpha particles or characteristic low-energy L X-ray photons associated w
33、ith the decay of the nuclide. It is designed to be a source that emits photons with an average energy of approximately 60 keV. This International Standard also specifies preferred reference radiations for the calibration of surface contamination monitors. These reference radiations are realized in t
34、he form of adequately characterized large area sources specified, without exception, in terms of surface emission rates which are traceable to national standards. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable fo
35、r its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 12749-2, Nuclear energy, nuclear technologies, and radiological protection Vocabulary Part 2: Radiological protection
36、 ISO/IEC 17025, General requirements for the competence of testing and calibration laboratories IEC 60050-395, International Electrotechnical Vocabulary Part 395: Nuclear instrumentation: Physical phenomena, basic concepts, instruments, systems, equipment and detectors 3 T erms a nd definiti ons For
37、 the purposes of this document, the terms and definitions given in ISO 12749-2, IEC 60050-395, and the following apply. 3.1 surface emission ratenumber of particles or photons of a given type above a given energy emerging from the face of the source or its window per time in a mass-free environment
38、3.2 facevertical projection of the nominal active area onto the front surface of the source Note 1 to entry: See Figure 1. INTERNATIONAL ST ANDARD ISO 8769:2016(E) ISO 2016 All rights reserved 1BS ISO 8769:2016ISO 8769:2016(E) 2 1 3 4 Key 1 filter 2 backing 3 face 4 nominal active area F i g u r e 1
39、 C r o s s -s e c t i o n a l d r a w i n g o f a s t a n d a r d s o u r c e w i t h i t s f i l t e r 3.3 saturation layer thicknessthickness of the medium equal to the maximum range of the specified particulate radiation 3.4 i n s t r u ment ef f ic ienc y ratio between the instrument net reading
40、 (counts per time after background subtraction) and the surface emission rate of the source (particles emitted per time) in a specified geometry relative to a source Note 1 to entry: The instrument efficiency depends on the energy of the radiation emitted by the source, the area of the source, and t
41、he area of the detector entrance window. 3.5 self-absorptionabsorption of radiation which occurs within the material of the source itself 3.6 uncertainty standard uncertainty (k = 1) unless otherwise stated Note 1 to entry: The treatment of uncertainties is in accordance with the ISO/IEC Guide 98-3
42、10to the Expression of Uncertainty in Measurement. 3.7 uniformityindication of the lack variation of that property over the surface 4 Traceability of reference sources The following scheme is proposed to ensure that working standards used in the field for the routine calibration of surface contamina
43、tion monitors shall be related to national measurement standards through a clearly defined traceability chain using reference sources and reference transfer instruments. Reference sources shall be of the following two types: Class 1: reference sources that have been calibrated directly in terms of a
44、ctivity and surface emission rate at a national or international metrology institute. Class 2: reference sources that have been calibrated in terms of surface emission rate on a reference transfer instrument, the efficiency of which has been measured by calibration with a Class 1 reference source of
45、 the same radionuclide and of the same general construction using the same geometry, at a laboratory that has been accredited to ISO 17025 for such measurements.2 ISO 2016 All rights reservedBS ISO 8769:2016ISO 8769:2016(E) National metrology institutes shall, at their discretion, provide the means
46、whereby Class 1 reference sources of a specified range of radionuclides may be certified by them. For those countries which are signatories to the Mutual Recognition Arrangement (MRA) 11 , a certificate of calibration from another participating institute in a second country is recognized as valid in
47、 the first country for the quantities, ranges, and measurement uncertainties specified in Appendix C of Reference 11. The activity and surface emission rate of Class 1 reference sources shall be measured, using, for example, a windowless gas-flow proportional detector, or by using an instrument that
48、 has been calibrated using sources that have been measured absolutely. Calibration procedures for activity determination are discussed for example, in References 12,13,14 and 15. Organizations with a requirement to type test and to calibrate instruments to be used for monitoring radioactive surface
49、contamination need to have access to suitable Class 1 or Class 2 reference sources. The purpose of a working source is to check the calibration of surface contamination monitors in the field; they are not to be confused with check sources which are only intended to verify that a monitor is operating. Organizations with a requirement to provide working standard sources for the routine confirmation of the calibration of their surface contamination monitoring instruments require access
