ISO 4037-2:2019
Radiological protection — 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 from 8 keV to 1,3 MeV and 4 MeV to 9 MeV
Radiological protection — 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 from 8 keV to 1,3 MeV and 4 MeV to 9 MeV
- Статус документа:
- Действующий
- Формат:
- Электронный (PDF)
- Количество страниц:
- 27
- Дата публикации:
- 18 января 2019 г.
- Издание:
- ISO IS 4037 edition 2 version 1
- ICS:
- 17.240
This document 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 and for air kerma rates above 1 µGy/h. The considered measuring quantities are the air kerma free-in-air, Ka, and the phantom related operational quantities of the International Commission on Radiation Units and Measurements (ICRU)[2], H*(10), Hp(10), H'(3), Hp(3), H'(0,07) and Hp(0,07), together with the respective dose rates. The methods of production are given in ISO 4037-1. This document can also be used for the radiation qualities specified in ISO 4037-1:2019, Annexes A, B and C, but this does not mean that a calibration certificate for radiation qualities described in these annexes is in conformity with the requirements of ISO 4037. The requirements and methods given in this document are targeted at an overall uncertainty (k = 2) of the dose(rate) of about 6 % to 10 % for the phantom related operational quantities in the reference fields. To achieve this, two production methods of the reference fields are proposed in ISO 4037-1. The first is to produce "matched reference fields", which follow the requirements so closely that recommended conversion coefficients can be used. The existence of only a small difference in the spectral distribution of the "matched reference field" compared to the nominal reference field is validated by procedures, which are given and described in detail in this document. For matched reference radiation fields, recommended conversion coefficients are given in ISO 4037-3 only for specified distances between source and dosemeter, e.g., 1,0 m and 2,5 m. For other distances, the user has to decide if these conversion coefficients can be used. The second method is to produce "characterized reference fields". Either this is done by determining the conversion coefficients using spectrometry, or the required value is measured directly using secondary standard dosimeters. This method applies to any radiation quality, for any measuring quantity and, if applicable, for any phantom and angle of radiation incidence. The conversion coefficients can be determined for any distance, provided the air kerma rate is not below 1 µGy/h. Both methods require charged particle equilibrium for the reference field. However this is not always established in the workplace field for which the dosemeter shall be calibrated. This is especially true at photon energies without inherent charged particle equilibrium at the reference depth d, which depends on the actual combination of energy and reference depth d. Electrons of energies above 65 keV, 0,75 MeV and 2,1 MeV can just penetrate 0,07 mm, 3 mm and 10 mm of ICRU tissue, respectively, and the radiation qualities with photon energies above these values are considered as radiation qualities without inherent charged particle equilibrium for the quantities defined at these depths. This document is not applicable for the dosimetry of pulsed reference fields.
Abstract
Overview
ISO 4037-2:2019 - Radiological protection - Dosimetry for X and gamma reference radiation - defines procedures for dosimetry used to calibrate dosemeters and doserate meters and to determine their response as a function of photon energy. The standard covers photon energy ranges ≈ 8 keV to 1.3 MeV and 4 MeV to 9 MeV, and applies for air kerma rates above 1 µGy/h. Measured quantities include air kerma free‑in‑air (Ka) and the ICRU phantom‑related operational quantities H(10), Hp(10), H'(3), Hp(3), H'(0.07) and Hp(0.07)* and their dose rates.
Key topics and technical requirements
- Two reference‑field approaches
- Matched reference fields: produced to closely meet ISO 4037‑1 requirements so that recommended conversion coefficients (see ISO 4037‑3) may be used - coefficients are given for specified source‑to‑dosemeter distances (e.g., 1.0 m and 2.5 m).
- Characterized reference fields: conversion coefficients are determined by spectrometry or direct measurement with secondary standard dosimeters; applicable for any radiation quality, distance (subject to Ka ≥ 1 µGy/h), phantom and angle.
- Primary dosimetric quantity: air kerma free‑in‑air (Ka) and conversion to phantom‑related operational quantities using validated coefficients.
- Measurement methods and instrumentation
- Use of secondary standard instruments (nearly constant energy dependence) and ionization chambers.
- Detailed procedures for geometry, chamber support, stem scatter, positioning and orientation.
- Required corrections: temperature, pressure, humidity, radiation‑induced leakage, incomplete ion collection, beam non‑uniformity.
- Uncertainty target: overall uncertainty (k = 2) for phantom‑related operational quantities of approximately 6% to 10%.
- Special considerations: gamma‑ and X‑ray specific procedures (source certification, decay, output stability, monitoring); not applicable to pulsed reference fields.
- Charged particle equilibrium: addressed; note that certain photon energies do not establish inherent charged particle equilibrium at shallow depths. Example electron penetrations given: electrons >65 keV, 0.75 MeV and 2.1 MeV can just penetrate 0.07 mm, 3 mm and 10 mm of ICRU tissue, respectively.
Practical applications
- Calibration of workplace and personal dosemeters and dose‑rate meters used in radiation protection.
- Development and validation of reference radiation fields for calibration laboratories and national metrology institutes.
- Determination of instrument energy response and conversion coefficients via spectrometry or secondary standards.
- Establishing traceable measurement uncertainty budgets for regulatory compliance and quality assurance.
Who should use this standard
- Calibration laboratories and secondary standard dosimetry services
- National metrology institutes and accreditation bodies
- Health physics and radiation protection teams in nuclear, industrial and medical sectors
- Instrument manufacturers and test laboratories
Related standards
- ISO 4037‑1 (production and characterization of reference fields)
- ISO 4037‑3 (conversion coefficients and calibration methods for dosemeters/doserate meters)
- ISO 4037‑4 (low energy X reference fields)
- ICRU publications referenced for operational quantities
Keywords: ISO 4037-2:2019, radiological protection, X and gamma reference radiation, calibration, dosimetry, air kerma, H*(10), Hp(10), conversion coefficients, matched reference fields, characterized reference fields, ionization chamber.
Технические детали
- Технический комитет
- ISO/TC 85/SC 2 - Radiological protection
- SKU
- ISO 4037-2:2019
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