ISO 6980-1:2022
Nuclear energy — Reference beta-particle radiation — Part 1: Methods of production
Nuclear energy — Reference beta-particle radiation — Part 1: Methods of production
- Статус документа:
- Отменён
- Формат:
- Электронный (PDF)
- Количество страниц:
- 21
- Дата публикации:
- 1 ноября 2022 г.
- Издание:
- ISO IS 6980 edition 2 version 1
- ICS:
- 17.240
This document specifies the requirements for reference beta radiation fields produced by radioactive sources to be used for the calibration of personal and area dosemeters and dose-rate meters to be used for the determination of the quantities Hp(0,07), H'(0,07;Ω), Hp(3) and H'(3;Ω), and for the determination of their response as a function of beta particle energy and angle of incidence. The basic quantity in beta dosimetry is the absorbed-dose rate in a tissue-equivalent slab phantom. This document gives the characteristics of radionuclides that have been used to produce reference beta radiation fields, gives examples of suitable source constructions and describes methods for the measurement of the residual maximum beta particle energy and the dose equivalent rate at a depth of 0,07 mm in the International Commission on Radiation Units and Measurements (ICRU) sphere. The energy range involved lies between 0,22 and 3,6 MeV maximum beta energy corresponding to 0,06 MeV to 1,1 MeV mean beta energy and the dose equivalent rates are in the range from about 10 µSv·h–1 to at least 10 Sv·h–1. In addition, for some sources, variations of the dose equivalent rate as a function of the angle of incidence are given. However, as noted in ICRU Report 56[3], the ambient dose equivalent, H*(10), used for area monitoring, and the personal dose equivalent, Hp(10), as used for individual monitoring, of strongly penetrating radiation, are not appropriate quantities for any beta radiation, even that which penetrates 10 mm of tissue (Emax > 2 MeV). This document is applicable to two series of beta reference radiation fields, from which the radiation necessary for determining the characteristics (calibration and energy and angular dependence of response) of an instrument can be selected. Series 1 reference radiation fields are produced by radioactive sources used with beam-flattening filters designed to give uniform dose equivalent rates over a large area at a specified distance. The proposed sources of 106Ru/106Rh, 90Sr/90Y, 85Kr, 204Tl and 147Pm produce maximum dose equivalent rates of approximately 200 mSv·h–1. Series 2 reference radiation fields are produced without the use of beam-flattening filters, which allows large area planar sources and a range of source-to-calibration plane distances to be used. Close to the sources, only relatively small areas of uniform dose rate are produced, but this series has the advantage of extending the energy and dose rate ranges beyond those of series 1. The series also include radiation fields using polymethylmethacrylate (PMMA) absorbers to reduce the maximum beta particle energy. The radionuclides used are those of series 1; these sources produce dose equivalent rates of up to 10 Sv·h–1.
Abstract
Overview
ISO 6980-1:2022 - "Nuclear energy - Reference beta-particle radiation - Part 1: Methods of production" specifies how to produce and characterize reference beta-particle radiation fields from radioactive sources for the calibration of personal and area dosemeters and dose-rate meters. The standard defines the field characteristics, acceptable radionuclides, example source constructions and measurement methods for key calibration quantities such as Hp(0.07), H′(0.07;Ω), Hp(3) and H′(3;Ω). It focuses on absorbed-dose rate in a tissue-equivalent slab phantom and on measuring the residual maximum beta energy (Eres) and dose equivalent at 0.07 mm in the ICRU sphere.
Key topics and requirements
- Applicable energy and dose ranges
- Maximum beta energy (Emax): 0.22 to 3.6 MeV
- Mean beta energy: ≈0.06 to 1.1 MeV
- Dose equivalent rates: ~10 µSv·h⁻¹ up to at least 10 Sv·h⁻¹
- Two series of reference fields
- Series 1: Uses beam-flattening filters to provide large-area uniform fields (proposed radionuclides include 106Ru/106Rh, 90Sr/90Y, 85Kr, 204Tl, 147Pm) with maximum rates around 200 mSv·h⁻¹.
- Series 2: No beam-flattening filters; supports large planar sources, varied source-to-plane distances, PMMA absorbers to reduce beta energy and extends energy/dose ranges up to ~10 Sv·h⁻¹.
- Uniformity: Dose rate uniformity over detector area should be within ±5% for Eres ≥ 300 keV and ±10% for Eres < 300 keV.
- Photon contamination: Photon contribution to the selected dose quantity must be < 2% (Hphoton/Hbeta < 0.02).
- Stability: Prefer radionuclides with long half-lives (preferably > 1 year) to reduce emission-rate variation over time.
- Measurement procedures: Methods for determining Eres, absorbed dose at 0.07 mm in the ICRU sphere, and source characterization are specified (see ISO 6980-2 and ISO 6980-3 for measurement and calibration steps).
Applications and users
- Calibration laboratories and national metrology institutes performing radiation protection instrument calibrations
- Nuclear power plants, radiological protection services, emergency response teams and industrial users needing traceable calibration of personal and area dosemeters
- Manufacturers of dosemeters and dose-rate meters who require standardized test fields to characterize energy and angular response
- Regulatory bodies and health physics specialists establishing conformity and quality assurance for beta monitoring
Related standards
- ISO 6980 series: Part 2 (absorbed dose determination) and Part 3 (calibration procedures)
- ISO 29661 (reference radiation field definitions) and ICRU reports referenced for operational quantities and tissue-equivalent phantoms
Keywords: ISO 6980-1:2022, reference beta-particle radiation, calibration, dosemeters, Hp(0.07), H′(0.07;Ω), Hp(3), H′(3;Ω), 90Sr/90Y, 106Ru/106Rh, PMMA, ICRU sphere.
Технические детали
- Технический комитет
- ISO/TC 85/SC 2 - Radiological protection
- SKU
- ISO 6980-1:2022
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