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1、BRITISH STANDARD BS ISO 4037-2:1997 X and gamma reference radiation for calibrating dosemeters and doserate meters and for determining their response as a function of photon energy Part 2: Dosimetry for radiation protection over the energy ranges 8 keV to 1,3 MeV and 4 MeV to 9 MeV ICS 17.240 Licens
2、ed Copy: sheffieldun sheffieldun, na, Sun Nov 26 03:29:56 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 4037-2:1997 This British Standard, having been prepared under the direction of the Engineering Sector Board, was published under the authority of the Standards Board and comes into effect on 1
3、5 March 1998 BSI 05-1999 ISBN 0 580 29311 4 National foreword This British Standard reproduces verbatim ISO 4037-2:1997 and implements it as the UK national standard. It supersedes BS 5869:1980 which is withdrawn. The UK participation in its preparation was entrusted to Technical Committee NCE/2, He
4、alth physics instrumentation, which has the responsibility to: aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and Europea
5、n developments and promulgate them in the UK. A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Standard
6、s Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for
7、their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, the ISO title page, pages ii to iv, pages 1 to 25 and a back cover. This standard ha
8、s been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Amendments issued since publication Amd. No.DateComments Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 03:29:56 GMT+00:00 2006, Uncontrolled
9、 Copy, (c) BSI BS ISO 4037-2:1997 BSI 05-1999i Contents Page National forewordInside front cover Forewordiii Text of ISO 4037-21 Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 03:29:56 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ii blank Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26
10、03:29:56 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 03:29:56 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 4037-2:1997 ii BSI 05-1999 Contents Page Forewordiii Introduction1 1Scope1 2Normative references1 3Definitions1 4Apparatus4 5General p
11、rocedures4 6Procedures applicable to ionization chambers5 7Additional procedures and precautions specific to gamma radiation dosimetry using radionuclide sources7 8Additional procedures and precautions specific to X-radiation dosimetry8 9Special procedures and precautions specific to fluorescence X-
12、radiation Limitation of extraneous radiation in beams9 10Dosimetry of reference radiation at photon energies between 4 MeV and 9 MeV10 11Uncertainty of measurement19 Annex A (informative) Determination by ionization chamber measurements of air kerma under receptor-absent conditions and of absorbed d
13、ose to tissue (water) under receptor conditions21 Annex B (informative) Bibliography23 Figure 1 Example of a typical X-ray setup9 Figure 2 Example of setup for calibration of fluence detectors by means of associated particle counting 1916 Figure 3 Radiation geometries for in-phantom measurements, sh
14、owing cross-sections through two types of phantom: a sphere of 30 cm diameter and a parallelepiped of 30 cm 30 cm 20 cm17 Table 1 Typical values for the bremsstrahlung correction12 Table 2 Values for attenuation and scatter correction, katt, for different types of ionization chamber13 Table 3 Typica
15、l average restricted-mass collision-stopping powers of air relative to those of the wall materials13 Table 4 Typical energy absorption coefficients for non air-equivalent wall materials relative to air 1514 Descriptors: Nuclear radiation, radiation protection, radiation measuring instruments, exposu
16、re dose-rate meters, calibration, reference sources, gamma radiation, X rays, dosimetry. Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 03:29:56 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 4037-2:1997 BSI 05-1999iii Foreword ISO (the International Organization for Standardization) is a
17、 worldwide federation of national standards bodies (ISO member 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 represente
18、d on that committee. International organizations, governmental 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. Draft International Standards ad
19、opted 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. International Standard ISO 4037-2 was prepared by Technical Committee ISO/TC 85, Nuclear energy, Subcommi
20、ttee SC 2, Radiation protection. This first edition of ISO 4037-2, along with ISO 4037-1, cancels and replaces the first edition of ISO 4037:1979, which has been technically revised. ISO 4037 consists of the following parts, under the general title X and gamma reference radiation for calibrating dos
21、emeters and doserate meters and for determining their response as a function of photon energy. Part 1: Radiation characteristics and production methods; Part 2: Dosimetry of X and gamma reference radiation for radiation protection over the energy ranges 8 keV to 1,3 MeV and 4 MeV to 9 MeV; Part 3: C
22、alibration of area and personal dosemeters. Annex A and Annex B of this part of ISO 4037 are for information only. Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 03:29:56 GMT+00:00 2006, Uncontrolled Copy, (c) BSI iv blank Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 03:29:56 GMT+0
23、0:00 2006, Uncontrolled Copy, (c) BSI BSI 05-19991 BS ISO 4037-2:1997 Introduction The term “dosimetry” is used in this part of ISO 4037 to describe the method by which the value of a physical quantity characterizing the interaction of radiation with matter may be measured at a given point by the us
24、e of a calibrated standard instrument. Dosimetry is the basis for the calibration of radiation protection instruments and devices and the determination of their response as a function of the energy of the radiation of interest. At present, the quantities in which photon secondary-standard instrument
25、s or sources are calibrated for use in radiological protection calibration laboratories relate to measurements made in free air, i.e. air kerma. NOTEThroughout this part of ISO 4037, kerma is used as an abbreviation for air kerma. In order to correlate measured physical quantities with the magnitude
26、 of a biological effect, a quantity of the dose equivalent type 1 is required for use in radiation protection. ICRU has defined such quantities 2 and a further International Standard will be issued containing tables of conversion coefficients from air kerma to these dose equivalent quantities (see I
27、SO 4037-3). 1 Scope This part of ISO 4037 specifies the procedures for the dosimetry of X and gamma reference radiation for the calibration of radiation protection instruments over the energy range from approximately 8 keV to 1,3 MeV and from 4 MeV to 9 MeV. The methods of production and nominal ker
28、ma rates obtained from these reference radiations are given in ISO 4037-1. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this part of ISO 4037. At the time of the publication, the editions indicated were valid. All s
29、tandards are subject to revision, and parties to agreements based on the part of ISO 4037 are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 403
30、7-1:, X and gamma reference radiation for calibrating dosemeters and doserate meters and for determining their response as a function of photon energy Part 1: Radiation characteristics and production methods1). ISO 4037-3:, X and gamma reference radiation for calibrating dosemeters and doserate mete
31、rs and for determining their response as a function of photon energy Part 3: Calibration of area and personal dosemeters2). ICRU Report 33:1980, Radiation quantities and units. VIM, 1984, International Vocabulary of Basic and General Terms in Metrology, BIPM-IEC-ISO-OIML. 3 Definitions For the purpo
32、ses of this part of ISO 4037, the definitions given in ICRU Report 33, in the International Vocabulary of Basic and General Terms in Metrology (VIM) and the following definitions apply. 3.1 reference conditions conditions of use for a measuring instrument prescribed for performance testing or condit
33、ions to ensure valid comparison of results of measurements VIM NOTEThe reference conditions generally specify reference values or reference ranges for the parameters affecting the measuring instrument. For the purposes of this part of ISO 4037, the reference values for temperature, atmospheric press
34、ure and relative humidity are as follows: ambient temperature: 293,15 K; atmospheric pressure: 101,3 kPa; relative humidity: 65 %. 1) To be published. (Revision of ISO 4037:1979) 2) To be published. Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 03:29:56 GMT+00:00 2006, Uncontrolled Copy, (c
35、) BSI BS ISO 4037-2:1997 2 BSI 05-1999 3.2 standard test conditions value (or range of values) of the influence quantities VIM or instrument parameters that are specified for the dosimetry of the radiation fields NOTEThe range of values for ambient temperature, atmospheric pressure and relative humi
36、dity are as follows: ambient temperature: 291,15 K to 295,15 K; ambient pressure: 86 kPa to 106 kPa; relative humidity: 30 % to 75%. Working outside this range may result in reduced accuracy. 3.3 ionization chamber ionization detector consisting of a chamber filled with a suitable gas, in which an e
37、lectric field, insufficient to induce gas multiplication, is provided for the collection at the electrodes of charges associated with the ions and the electrons produced in the sensitive volume of the detector by the ionizing radiation 3 NOTEThe ionization chamber includes the sensitive volume, the
38、collecting and polarizing electrodes, the guard electrode, if any, the chamber wall, the parts of the insulator adjacent to the sensitive volume and any necessary caps to ensure electron equilibrium. 3.4 ionization chamber assembly ionization chamber and all other parts to which the chamber is perma
39、nently attached, except the measuring assembly NOTEFor a cable-connected chamber, it includes the stem, the electrical fitting and any permanently attached cable or pre-amplifier. For a thin-window chamber, it includes any block of material in which the ionization chamber is permanently embedded. 3.
40、5 measuring assembly device for measuring the current or charge from the ionization chamber and converting it into a form suitable for display, control or storage 3.6 reference point of the ionization chamber point to which the measurement of the distance from the radiation source to the chamber at
41、a given orientation refers NOTEThe reference point should be marked on the assembly by the manufacturer of the instrument. If this proves impossible, the reference point should be indicated in the accompanying documentation supplied with the instrument. 3.7 point of test location of the reference po
42、int of the ionization chamber for calibration purposes and at which the conventionally true kerma rate (see 3.11) is known 3.8 chamber orientation effect change in the ionization current from the ionization chamber as the directional incidence of the reference radiation is varied 3.9 calibration fac
43、tor ratio of the conventional true value of the quantity the instrument is intended to measure divided by the indication of the instrument, corrected to stated reference conditions 3.10 calibration factor factor which converts the ionization current or charge, corrected to reference conditions, to t
44、he conventional true value of the dosimetric quantity at the reference point of the chamber Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 03:29:56 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BSI 05-19993 BS ISO 4037-2:1997 3.11 true value value which characterizes a quantity perfectly define
45、d, in the conditions which exist when that quantity is considered NOTEThe true value of a quantity is an ideal concept and, in general, cannot be known exactly. Indeed, quantum effects may preclude the existence of a unique true value VIM. 3.12 conventional true value of a quantity best estimate of
46、the value of the quantity to be measured, determined by a primary or secondary standard or by a reference instrument that has been calibrated against a primary or secondary standard EXAMPLE: Within an organization, the result of a measurement obtained with a secondary standard instrument may be take
47、n as the conventional true value of the quantity to be measured. NOTEA conventional true value is, in general, regarded as being sufficiently close to the true value for the difference to be insignificant for the given purpose. 3.13 response ratio between the indication of the measuring assembly and
48、 the conventional true value of the measured quantity at the position of the reference point in space NOTEThe response usally varies with the spectral and directional distribution of the incident radiation. 3.14 response time time interval between the instant when a stimulus is subjected to a specif
49、ied abrupt change and the instant when the response reaches and remains within specified limits of its final steady value VIM 3.15 deviation from linearity percentage deviation from linearity given by: = 100 (mQ/Mq 1) where M and Q refer to the indication and input at a chosen test point, respectively; m is the indication observed for some other input signal q. NOTEFor multirange instruments, the above definition is applicable to each range. 3.16 leakage current total detector current flowing at the operating bias in
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