ISO/ASTM 51400:2003(E)

Standard Practice for

Characterization and Performance of a High-Dose Radiation
Dosimetry Calibration Laboratory1
This standard is issued under the fixed designation ISO/ASTM 51400; the number immediately following the designation indicates the
year of original adoption or, in the case of revision, the year of last revision.

1. Scope E 2116 Practice for Dosimetry for a Self-Contained Dry-

1.1 This practice addresses the specific requirements for Storage Gamma-Ray Irradiator2
laboratories engaged in dosimetry calibrations involving ion- 2.2 ISO/ASTM Standards:
izing radiation, namely, gamma-radiation, electron beams or 51261 Guide for Selection and Calibration of Dosimetry
X-radiation (bremsstrahlung) beams. It specifically describes Systems for Radiation Processing2
the requirements for the characterization and performance 51707 Guide for Estimating Uncertainties in Dosimetry for
criteria to be met by a high-dose radiation dosimetry calibra- Radiation Processing2
tion laboratory. 2.3 International Organization for Standardization Docu-
1.2 The absorbed-dose range is typically between 10 and ments:
105 Gy. ISO/IEC 17025 (1999) General Requirements for the Com-
1.3 This practice addresses criteria for laboratories seeking petence of Calibration and Testing Laboratories3
accreditation for performing high-dose dosimetry calibrations, 2.4 International Commission on Radiation Units and
and is a supplement to the general requirements described in Measurements (ICRU) Reports:
ISO/IEC 17025. ICRU Report 60, Fundamental Quantities and Units for
1.3.1 By meeting these criteria and those in ISO/IEC 17025, Ionizing Radiation4
the laboratory may be accredited by a recognized accreditation 3. Terminology
organization.
1.3.2 Adherence to these criteria will help to ensure high 3.1 Definitions:
standards of performance and instill confidence regarding the 3.1.1 accredited dosimetry calibration laboratory—a do-
competency of the accredited laboratory with respect to the simetry laboratory that has formal recognition that it is
services it offers. competent to carry out specific calibrations in accordance with
1.4 This standard does not purport to address all of the documented requirements of a recognized accreditation orga-
safety concerns, if any, associated with its use. It is the nization.
responsibility of the user of this standard to establish appro- 3.1.2 calibration—the process whereby the response of a
priate safety and health practices and determine the applica- dosimeter or measuring instrument is characterized through
bility of regulatory limitations prior to use. comparison with an appropriate standard that is traceable to,
and consistent with, a nationally or internationally recognized
2. Referenced documents standard.
2.1 ASTM Standards: 3.1.3 dosimetry system—a system used for determining
E 170 Terminology Relating to Radiation Measurements absorbed dose, consisting of dosimeters, measurement instru-
and Dosimetry2 ments and their associated reference standards, and procedures
E 1249 Practice for Minimizing Dosimetry Errors in Radia- for the system’s use.
tion Hardness Testing of Silicon Electronic Devices Using 3.1.4 measurement quality assurance plan—a documented
Co-60 Sources2 program for the measurement process that ensures, on a
E 1250 Test Method for Application of Ionization Cham- continuing basis, that the overall uncertainty meets the require-
bers to Assess the Low Energy Gamma Component of ments of the specific application. This plan requires traceability
Cobalt-60 Irradiators Used in Radiation-Hardness Testing to, and consistency with, nationally or internationally recog-
of Silicon Electronic Devices2 nized standards.
3.1.5 measurement traceability—the ability to demonstrate
by means of an unbroken chain of comparisons that a mea-
1
This practice is under the jurisdiction of ASTM Committee E10 on Nuclear surement is in agreement within acceptable limits of uncer-
Technology and Applications and is the direct responsibility of Subcommittee tainty with comparable nationally or internationally recognized
E10.01 on Dosimetry for Radiation Processing, and is also under the jurisdiction of
ISO/TC 85/WG 3. standards.
Current edition approved May 28, 2003. Published July 15, 2003. Originally
published as ASTM E 1400 – 91. ASTM E 1400 – 95ae1 was adopted by ISO in
3
1998 with the intermediate designation ISO 15560:1998(E). The present Interna- Available from International Organization for Standardization (ISO), 1 Rue de
tional Standard ISO/ASTM 51400:2003(E) replaces ISO 15560 and is a major Varembé, Case Postale 56, CH-1211, Geneva 20, Switzerland.
4
revision of the last previous edition ISO/ASTM 51400:2002(E). Available from International Commission on Radiation Units and Measure-
2
Annual Book of ASTM Standards, Vol 12.02. ments, 7910 Woodmont Ave., Suite 800, Bethesda, MD 20814, USA.

© ISO/ASTM International 2003 – All rights reserved 1

ISO/ASTM 51400:2003(E)

3.1.6 primary-standard dosimeter—a dosimeter of the high- 4.2.3 periodic performance evaluations, including profi-
est metrological quality, established and maintained as an ciency tests and on-site expert assessments.5
absorbed-dose standard by a national or international standards 4.3 When a calibration laboratory applies for accreditation,
organization. the accreditation organization (see Annex A1) determines
3.1.7 proficiency testing—evaluation of the measurement whether the laboratory’s quality documentation is satisfactory,
capability of a calibration laboratory and demonstration of performs proficiency tests for each calibration category for
consistency with appropriate national standards. which accreditation is requested, and provides technical ex-
3.1.8 quality assurance—all systematic actions necessary to perts for on-site assessments to determine whether the labora-
provide adequate confidence that a calibration, measurement or tory meets the criteria of this practice, the accreditation
process is performed to a predefined level of quality. organization and those of ISO/IEC 17025.
3.1.9 quality control—the operational techniques and pro- 4.4 Section 5 sets forth specific criteria for laboratories
cedures that are employed routinely to achieve and sustain a engaged in dosimetry calibrations involving ionizing radiation,
predefined level of quality. that is, gamma-radiation, electron beams and X-radiation
3.1.10 quality manual—document stating the quality policy, (bremsstrahlung) beams. This section amplifies and interprets
quality system, and quality practices of an organization. the general requirements of ISO/IEC 17025.
3.1.11 quality system—documented organizational struc-
ture, responsibilities, procedures, processes, and resources for 5. Specific criteria for ionizing radiation
implementing quality management. 5.1 This section sets specific requirements to which a
3.1.12 radiation processing—the intentional irradiation of laboratory shall adhere if it is to be accredited for dosimetry
products or materials to preserve, modify, or improve their calibrations involving ionizing radiation, specifically gamma-
characteristics. radiation, electron beams and X-radiation (bremsstrahlung)
3.1.13 recognized accreditation organization—an organiza- beams. This section amplifies and interprets certain general
tion, operating in conformance with national regulations or requirements set forth in ISO/IEC 17025.
requirements, that conducts and administers a laboratory ac- 5.2 This section is to be used in conjunction with ISO/IEC
creditation program and grants accreditation to calibration 17025 to assess ionizing radiation dosimetry calibration labo-
laboratories. ratories for the purpose of accreditation by an appropriate
3.1.14 reference-standard dosimeter—a dosimeter of high accreditation organization.
metrological quality used as a standard to provide measure-
5.3 This section may also be used with ISO/IEC 17025 as a
ments traceable to, and consistent with, measurements made
guide by ionizing radiation dosimetry calibration laboratories
using primary-standard dosimeters.
in the development and implementation of their quality sys-
3.1.15 transfer-standard dosimeter—a dosimeter, often a
tems.
reference-standard dosimeter suitable for transport between
5.4 Quality System, Assessment and Review:
different locations, used to compare absorbed-dose measure-
5.4.1 The quality manual and related quality documentation
ments.
shall contain:
3.2 Definitions of other terms used in this standard that
5.4.1.1 A statement of the scope of the laboratory’s work for
pertain to radiation measurement and dosimetry may be found
which accreditation is sought, including the radiation types,
in ASTM Terminology E 170. Definitions in E 170 are com-
energies, and dose rates, and
patible with ICRU 60; that document, therefore, may be used
as an alternative reference. 5.4.1.2 Documentation of the model and serial numbers of
each critical piece of equipment used in a particular calibration.
4. Significance and use 5.4.2 The laboratory’s proficiency shall be tested at a
4.1 The radiation industry needs reliable, prompt dosimetry frequency specified by the accreditation organization.
calibration services to support accurate measurements of ab- 5.4.2.1 The proficiency tests of the calibration laboratory
sorbed dose. These measurements should be consistent with, shall be performed by a nationally or internationally recog-
and traceable to, the physical measurement standards main- nized standards laboratory.
tained by an appropriate national or international standards 5.4.2.2 The acceptable level of performance in the profi-
laboratory. Organizations that provide calibration services, and ciency test shall be determined by the accreditation organiza-
thereby serve as a link to national standards, include universi- tion. Typically, the absorbed-dose rate (or absorbed dose)
ties, government-owned laboratories, and private companies. measured in the calibration laboratory is within 4 %, at the
4.2 To ensure the provision of adequate services, a calibra- 95 % level of confidence, of the value defined by comparison
tion laboratory should be operating with a full measurement with the appropriate national or international standard.
quality assurance (MQA) plan. The fundamental requirements 5.5 Personnel:
for such a program include:
4.2.1 compliance with operational requirements of this
practice and those of ISO/IEC 17025, 5
Inn, K. G. W., Coursey, B. M., Eisenhower, E. H., Walker, M. D., Humphreys,
4.2.2 documented procedures and in-house quality assur- J. C., Heaton, H. T., and Duvall, K. C.,“The Role of the Office of Radiation
ance (QA) program specific to the calibration services pro- Measurement in Quality Assurance,” The Science of the Total Environment, 130/131
vided, and Elsevier Science Publishers B. V., Amsterdam, 1993, pp. 497–507.

2 © ISO/ASTM International 2003 – All rights reserved

 ISO/ASTM 51400:2003(E)

5.5.1 It is recommended that the laboratory’s technical (bremsstrahlung) radiation sources, the fluence rate should be
manager have a post-secondary degree awarded by a recog- sufficient to deliver an absorbed dose within the range of 10 to
nized educational institution, preferably in physical science, as 105 Gy within a reasonable time interval.
well as experience in radiation metrology or a closely related 5.7.2 Characterization of the Radiation Field:
scientific field. 5.7.2.1 Determine the absorbed-dose rate using a reference-
5.5.2 It is recommended that the supervisor of the calibra- standard dosimetry system in each location in which dosim-
tion laboratory has experience in radiation metrology or a eters are irradiated. Ensure that dosimeters are irradiated in the
closely related scientific field. locations where the dose rate is determined. At the time of
5.6 Facilities and Environment: accreditation and at intervals not to exceed those specified by
5.6.1 Suitable storage facilities shall be provided for refer- the accreditation organization (generally, one year or less),
ence standards, equipment, documented instructions, manuals, demonstrate that the dose-rate measurements are traceable to
and calibration certificates and reports. appropriate national standards by direct measurement inter-
5.6.2 Environmental monitoring equipment shall be pro- comparisons.
vided for recording temperature and relative humidity within 5.7.2.2 Ensure that the uniformity of the absorbed-dose rate
the laboratory. If interpretation of the response of a particular over the irradiation volume at each irradiation position has
type of dosimeter requires a history of the environmental been quantified. Typically, the absorbed-dose rate should not
conditions, the temperature and humidity shall be recorded. vary more than 61 %.
5.6.3 Although strict temperature control is not essential, it 5.7.2.3 Monitor and control the temperature of the dosim-
is recommended that the laboratory be kept at a reasonably eter during irradiation to the accuracy required by the charac-
uniform temperature so that the accuracy of equipment is not teristics of the dosimeter. Measure this temperature during a
adversely affected, and so that an adequate stability is achieved simulated irradiation of dosimeters or in a manner that will not
before the start of calibration measurements. It is recom- perturb the radiation field during the irradiation of dosimeters.
mended that the laboratory temperature be maintained within 5.7.2.4 If required, the photon or electron energy spectrum
the range of 15 to 25°C. The degree of environmental control should be known at the dosimeter location.
may have to be more stringent for some applications. 5.7.3 Reference Standards:
5.6.4 It is recommended that the relative humidity be 5.7.3.1 The laboratory shall have reference standards and/or
maintained within the range of 15 to 65 % for laboratory transfer standards that cover the range of calibrations per-
operation unless the calibration of specific dosimeter types formed.
requires a different range. 5.8 Measurement Traceability and Calibration:
5.6.5 A closely controlled environment is not normally
5.8.1 The reference standards used by the laboratory shall
necessary in a storage area, but wide temperature and humidity
be traceable to a national or international standards laboratory.
fluctuations should be avoided so as to protect instruments and
5.8.2 The standards or equipment originally calibrated by
physical standards temporarily held there, and to minimize the
comparison with a higher-level standard shall be recalibrated
time required for an instrument to reach equilibrium when
when the need is demonstrated by the results of proficiency
brought to the operational area from the storage area. Any area
testing or routine quality control.
used for storage of dosimeters shall have its temperature and
relative humidity controlled as required for the specific dosim- 5.9 Records:
etry system employed. 5.9.1 The laboratory’s permanent records shall include:
5.6.6 Fluorescent lamps, sunlight, and other sources of 5.9.1.1 The date, customer name, description of the dosim-
ultraviolet light shall be filtered if the dosimeters are adversely eters calibrated, the batch number or serial number, details of
affected by ultraviolet radiation. the service provided, and calibration report or certificate
5.6.7 The electrical power shall be appropriate to the number,
equipment used, suitably stable, and free of switching surges 5.9.1.2 Documentation of routine quality control actions
and significant line noise. When necessary, local auxiliary and any resultant control charts, and
voltage stabilizers and filters shall be used. 5.9.1.3 The results of all proficiency testing.
5.6.8 The laboratory shall be provided with an adequate 5.10 Certificates and Reports:
electrical grounding system. Where there is a possibility of 5.10.1 Calibration certificates or reports shall include an
interference arising from equipment connected to a single appropriate statement clearly specifying the conditions under
grounding system, use separate grounding systems taking which the calibrations or measurements were performed,
adequate precautions to avoid interference from interconnec- including the type of radiation (gamma-radiation, X-radiation,
tions between systems. or electron beam), the dose rate(s), temperature, and for
5.6.9 If compressed air is used, a pressure regulator and electron beams, the electron energy, pulse width, dose rate
means for removing moisture, dust, and oil from the com- within the pulse, and pulse repetition rate.
pressed air shall be provided. 5.10.2 Certificates or reports should state that application of
5.7 Equipment: the calibration results to an individual measurement is the
5.7.1 Radiation Source(s)—For a laboratory that utilizes responsibility of the user, and that care must be exercised in
gamma (60Co or 137Cs), electron beam and/or X-radiation interpolation of the calibration results.

© ISO/ASTM International 2003 – All rights reserved 3

ISO/ASTM 51400:2003(E)

5.10.3 The laboratory shall indicate whether the calibration NOTE 2—ISO/ASTM Guide 51707 defines possible sources of uncer-
was performed using either an accredited or non-accredited tainty in dosimetry performed in radiation processing facilities, and offers
procedure. The use of non-accredited procedures shall be procedures for estimating the magnitude of the resulting uncertainties in
the measurement of absorbed dose using a dosimetry system. The
justified and those procedures completely explained and docu- document defines and discusses basic concepts of measurement, including
mented. estimation of the measured value of a quantity, “true” value, error and
5.10.4 If the calibration laboratory discovers a discrepancy uncertainty. Components of uncertainty are discussed and methods are
in a calibration report, the person or institution that received provided for estimating their values. Methods are also provided for
the report shall be immediately notified. The discrepancy shall calculating the combined standard uncertainty and estimating expanded
be corrected as soon as possible, either by sending a corrected (overall) uncertainty.
report to the client or by recalibrating a new group of 6.4 The components of uncertainty involved in a measure-
dosimeters, as applicable. The laboratory shall determine the ment shall be estimated or determined. The overall uncertainty
reason for the discrepancy and take action necessary to prevent in the measurement may be estimated from a combination of
recurrences. The severity of the discrepancy in a calibration these components, and the procedure for combining these
may require notification to the accreditation organization in components shall be specifically stated or referenced in all
accordance with the policies of the accreditation organization. results.
6.5 The laboratory shall be capable of providing a service
6. Measurement uncertainty within the following indicated expanded uncertainty for a
6.1 To be meaningful, a measurement of absorbed dose shall coverage factor k = 2 (which corresponds approximately to a
be accompanied by an estimate of uncertainty. 95 % level of confidence). These values include an assumed
6.2 Components of uncertainty shall be identified as belong- uncertainty of 62 % (coverage factor k = 2) associated with
ing to one of two categories: the national standard.
6.2.1 Type A—those evaluated by statistical methods, or 6.5.1 Irradiation of dosimeters to a specified absorbed dose:
6.2.2 Type B—those evaluated by other means. 64 %.
6.3 Other ways of categorizing uncertainty have been 6.5.2 Evaluation of transfer-standard dosimeters supplied by
widely used and may be useful for reporting uncertainty. For the laboratory to customer for irradiation: 66 %.
example, the terms precision and bias or random and system- 6.6 The uncertainty value provided for the national standard
atic (non-random) are used to describe different categories of may change and hence require an adjustment of the other two
uncertainty. associated uncertainty values of 6.5.1 and 6.5.2. It shall be the
NOTE 1—The identification of Type A and Type B uncertainties is based responsibility of the calibration laboratory to notify each
on methodology for estimating uncertainties published in 1993 by the affected customer of any such changes, and the corrected
International Organization for Standardization (ISO) in the Guide to the values of all affected quantities previously reported to that
Expression of Uncertainty in Measurement.6 The purpose of using this customer.
type of characterization is to promote an understanding of how uncertainty
statements are arrived at and to provide a basis for the international 7. Keywords
comparison of measurement results.
7.1 absorbed dose; accreditation; calibration laboratory; do-
simeter; dosimetry system; electron beam; gamma-radiation;
6
Guide to the Expression of Uncertainty in Measurement, International Organi- ionizing radiation; radiation processing; reference-standard
zation for Standardization, 1993, ISBN 92-67-10188-9. dosimeter; transfer-standard dosimeter; X-radiation

4 © ISO/ASTM International 2003 – All rights reserved

 ISO/ASTM 51400:2003(E)

ANNEX

(informative)

A1. EXAMPLES OF ACCREDITATION ORGANIZATIONS

A1.1 At the international level, recognized accreditation National Cooperation for Laboratory Accreditation (NACLA).
organizations are signatories to the International Laboratory The National Voluntary Laboratory Accreditation Program
Accreditation Cooperation (ILAC). With approximately 37 (NVLAP), operated by the U.S. National Institute of Standards
members, ILAC includes accreditation organizations in Eu- and Technology (NIST), is a signatory to NACLA. NVLAP
rope, the European Cooperation for Accreditation (EA), and in accredits calibration laboratories in many fields including
the Asian Pacific Rim, Asian Pacific Laboratory Accreditation ionizing radiation. It provides the administrative organization
Cooperation (APLAC). for the accreditation process, arranges for proficiency testing
by NIST technical groups, and provides technical experts for
A1.2 In the United States of America, a recognized on-site assessment of the competence of the calibration labo-
accreditation organization is one that is a signatory to the ratory requesting accreditation.

ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentioned
in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk
of infringement of such rights, are entirely their own responsibility.

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Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States. Individual reprints (single or multiple copies) of this
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© ISO/ASTM International 2003 – All rights reserved 5