1、BRITISH STANDARD BS ISO 6980-2:2004 Nuclear energy Reference beta-particle radiation Part 2: Calibration fundamentals related to basic quantities characterizing the radiation field ICS 17.240 BS ISO 6980-2:2004 This British Standard was published under the authority of the Standards Policy and Strat
2、egy Committee on 18 October 2004 BSI 18 October 2004 ISBN 0 580 44620 4 National foreword This British Standard reproduces verbatim ISO 6980-2:2004 and implements it as the UK national standard. In addition to BS ISO 6980-1 and BS ISO 6980-3, it partially supersedes BS ISO 6980:1996 which will be wi
3、thdrawn upon publication of all three parts. The UK participation in its preparation was entrusted to Technical Committee NCE/2, Radiation protection and measurement, which has the responsibility to: A list of organizations represented on this committee can be obtained on request to its secretary. C
4、ross-references The British Standards which implement international publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British S
5、tandards Online. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to
6、the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside
7、front cover, the ISO title page, pages ii to iv, pages 1 to 36, an inside back cover and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. Date Comments Reference number ISO 6980-2:2004(E) OSI 4
8、002INTERNATIONAL STANDARD ISO 6980-2 Premire edition 2004-10-15 Nuclear energy Reference beta-particle radiation Part 2: Calibration fundamentals related to basic quantities characterizing the radiation field nergie nuclaire Rayonnements bta de rfrence Partie 2: Concepts dtalonnage en relation avec
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14、02 Allr ithgsr esedevrBSISO69802:2004IS-0896 O2:(4002E) I SO 4002 All irthgs ersedevr iiiContents Page Foreword iv 1 Scope 1 2 Normative references . 1 3 Terms and definitions. 2 4 Calibration and traceability of reference radiation fields . 4 5 General principles for calibrations of radionuclide be
15、ta-particle fields 5 5.1 General. 5 5.2 Scaling to derive equivalent thicknesses of various materials 5 5.3 Characterization of the radiation field in terms of penetrability 6 6 Calibration procedures using the extrapolation chamber 6 6.1 General. 6 6.2 Determination of the reference beta-particle a
16、bsorbed-dose rate. 7 7 Calibrations with other measurement devices 8 7.1 Calibrations with thermoluminescence dosemeters. 8 7.2 Calibrations with thermally stimulated exo-electron emission dosemeters 8 7.3 Calibrations with ionization chambers . 8 7.4 Calibrations with scintillator detectors. 9 8 Me
17、asurements at non-perpendicular incidence 9 9 Uncertainties . 9 Annex A (informative) List of symbols . 16 Annex B (normative) Extrapolation chamber measurements 19 Annex C (normative) Extrapolation chamber measurement correction factors 23 Annex D (informative) Example of an uncertainty analysis .
18、31 Bibliography . 35 BSISO69802:2004IS-0896 O2:(4002E) iv I SO 4002 All irthgs ersedevrForeword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out t
19、hrough 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, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO colla
20、borates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Sta
21、ndards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements o
22、f this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 6980-2 was prepared by Technical Committee ISO/TC 85, Nuclear energy, Subcommittee SC 2, Radiation protection. It is the second of a set of three standards concer
23、ning the production, calibration and use of beta-particle reference radiation fields for the calibration of dosemeters and dose-rate meters for protection purposes. The first standard in this series, ISO 6980-1 (being prepared), describes the methods of production and characterization of the referen
24、ce radiation. The third standard in the series, ISO 6980-3 (being prepared), describes procedures for the calibration of dosemeters and dose-rate meters and the determination of their response as a function of beta energy and angle of incidence. This standard, the second in the series, supersedes IS
25、O 6980:1996 and expands upon the calibration information provided in it. This standard describes procedures for the determination of absorbed-dose rate to a reference depth of tissue from beta- particle reference radiation fields. ISO 6980 consists of the following parts, under the general title Nuc
26、lear energy Reference beta-particle radiation: Part 1: Method of production Part 2: Calibration fundamentals related to basic quantities characterizing the radiation field Part 3: Calibration of area and personal dosimeters and determination of their response as a function of energy and angle of inc
27、idence BSISO69802:2004INTENRATIONAL TSANDADR IS-0896 O2:(4002E)I SO 4002 All irthgs ersedevr 1Nuclear energy Reference beta-particle radiation Part 2: Calibration fundamentals related to basic quantities characterizing the radiation field 1 Scope This part of ISO 6980 specifies methods for the measu
28、rement of the directional absorbed-dose rate in a tissue-equivalent slab phantom in the ISO 6980 reference beta-particle radiation fields. The energy range of the beta-particle-emitting isotopes covered by these reference radiations is 0,066 to 3,54 MeV (maximum energy). Radiation energies outside t
29、his range are beyond the scope of this standard. While measurements in a reference geometry (depth of 0,07 mm at perpendicular incidence in a tissue-equivalent slab phantom) with a reference class extrapolation chamber are dealt with in detail, the use of other measurement systems and measurements i
30、n other geometries are also described, although in less detail. The ambient dose equivalent, H*(10) as used for area monitoring of strongly penetrating radiation, is not an appropriate quantity for any beta radiation, even for that penetrating a 10 mm thick layer of ICRU tissue (i.e. E max 2 MeV). I
31、f adequate protection is provided at 0,07 mm, only rarely will one be concerned with other depths, for example 3 mm. This document is geared towards organizations wishing to establish reference-class dosimetry capabilities for beta particles, and serves as a guide to the performance of dosimetry wit
32、h the reference class extrapolation chamber for beta-particle dosimetry in other fields. Guidance is also provided on the statement of measurement uncertainties. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, on
33、ly the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. VIM:1993, International Vocabulary of Basic and General Terms in Metrology, second edition BIPM, IEC, IFCC, ISO, IUPAC, IUPAP, OIML ISO 6980:1996, Reference beta ra
34、diations for calibrating dosemeters and dose-rate meters and for determining their response as a function of beta-radiation energy ICRU 31:1979, Average Energy Required to Produce an Ion Pair ICRU 37:1984, Stopping Powers for Electrons and Positrons ICRU 39:1985, Determination of Dose Equivalents Re
35、sulting from External Radiation Sources ICRU 44:1989, Tissue Substitutes in Radiation Dosimetry and Measurement ICRU 51:1993, Quantities and Units in Radiation Protection Dosimetry ICRU 56:1997, Dosimetry of External Beta Rays for Radiation Protection BSISO69802:2004IS-0896 O2:(4002E) 2 I SO 4002 Al
36、l irthgs ersedevr3 Terms and definitions For the purposes of this document, the terms and definitions given in ICRU Report 51, the International Vocabulary VIM:1993 and the following apply. 3.1 extrapolation curve curve given by a plot of the corrected ionization current versus the extrapolation cha
37、mber depth 3.2 ICRU tissue material with a density of 1 gcm 3and a mass composition of 76,2 % oxygen, 10,1 % hydrogen, 11,1 % carbon, and 2,6 % nitrogen (see ICRU Report 39) 3.3 ionization chamber ionizing radiation detector consisting of a chamber filled with a suitable gas (almost always air), in
38、which an electric field, insufficient to induce gas multiplication, is provided for the collection at the electrodes of charges associated with the ions and electrons produced in the measuring volume of the detector by ionizing radiation NOTE The ionization chamber includes the measuring volume, the
39、 collecting and polarizing electrodes, the guard electrode, if any, the chamber wall, the parts of the insulator adjacent to the sensitive volume and any additional material placed over the ionization chamber to simulate measurement at depth. 3.3.1 extrapolation (ionization) chamber ionization chamb
40、er capable of having an ionization volume which is continuously variable to a vanishingly small value by changing the separation of the electrodes and which allows the user to extrapolate the measured ionization density to zero collecting volume 3.4 ionization density ratio of measured ionization pe
41、r unit volume of air 3.5 leakage current Bionization chamber current measured at the operating bias in the absence of radiation 3.6 maximum beta energy E maxhighest value of the energy of beta particles emitted by a particular nuclide which may emit one or several continuous spectra of beta particle
42、s with different maximum energies 3.7 parasitic current pnegative current produced by beta particles stopped in the collecting portion of the collecting electrode and diffusing to this electrode and the wire connecting this electrode to the electrometer connector 3.8 phantoms objects constructed to
43、simulate the scattering and attenuation properties of the human body NOTE In principle, the ISO water slab phantom, ISO rod phantom or the ISO pillar phantom should be used 19. For the purposes of this standard, however, a polymethylmethacrylate (PMMA) slab, 10 cm 10 cm in cross-sectional area by 5
44、cm thick, is sufficient to simulate the backscattering properties of the trunk of the human body, while tissue-equivalent materials such as polyethylene terephthalate (PET) are sufficient to simulate the attenuation properties of human tissue (see 5.2). BSISO69802:2004IS-0896 O2:(4002E) I SO 4002 Al
45、l irthgs ersedevr 33.9 reference conditions conditions which represent the set of influence quantities for which the calibration factor is valid without any correction NOTE 1 The reference conditions for the quantity to be measured may be chosen freely in agreement with the properties of the instrum
46、ent to be calibrated. The quantity to be measured is not an influence quantity. NOTE 2 For the purposes of this International Standard, the reference values for temperature, atmospheric pressure and relative humidity are as follows: ambient temperature: T 0= 293,15 K atmospheric pressure: p 0= 101,3
47、 kPa relative humidity: r 0= 0,65 3.10 reference point of a dosemeter point which is placed at the point of test for calibrating or testing purposes NOTE 1 The point of test is the location of the reference point of the extrapolation chamber at which the conventionally true value is determined durin
48、g calibration. NOTE 2 The distance of measurement refers to the distance between the radiation source and the reference point of the dosemeter. 3.10.1 reference point of the extrapolation chamber point to which the measurement of the distance from the radiation source to the chamber at a given orien
49、tation refers; the reference point is the centre of the back surface of the high-voltage electrode of the chamber 3.11 reference absorbed dose D Rpersonal absorbed dose, D p(0,07), in a slab phantom made of ICRU tissue with an orientation of the phantom in which the normal to the phantom surface coincides with the (mean) direction of the incident radiation NOTE 1 The personal absorbed dose D p(0,07) is defined in IC
