ISO/ASTM 52628:2013

Standard practice for dosimetry in radiation processing

ISO/ASTM 52628:2013 describes the basic requirements that apply when making absorbed dose measurements in accordance with the ASTM E61 series of dosimetry standards. In addition, it provides guidance on the selection of dosimetry systems and directs the user to other standards that provide specific information on individual dosimetry systems, calibration methods, uncertainty estimation and radiation processing applications. ISO/ASTM 52628:2013 applies to dosimetry for radiation processing applications using electrons or photons (gamma- or X-radiation). ISO/ASTM 52628:2013 addresses the minimum requirements of a measurement management system, but does not include general quality system requirements.

Pratique standard pour dosimétrie au traitement par irradiation

General Information

• Status: Withdrawn
• Publication Date: 08-Dec-2013
• Withdrawal Date: 08-Dec-2013
• ICS: 17.240 - Radiation measurements
• Technical Committee: ISO/TC 85 - Nuclear energy, nuclear technologies, and radiological protection
• Drafting Committee: ISO/TC 85 - Nuclear energy, nuclear technologies, and radiological protection
• Current Stage: 9599 - Withdrawal of International Standard
• Completion Date: 01-Apr-2020

Relations

• Revised: ISO/ASTM 52628:2020 - Standard practice for dosimetry in radiation processing
• Effective Date: 23-Apr-2020

Standards Content (Sample)

INTERNATIONAL ISO/ASTM
STANDARD 52628
First edition
2013-11-15
Practice for dosimetry in radiation pro-
cessing
Pratique standard pour dosimétrie au traitement par irradiation
Reference number
ISO/ASTM 52628:2013(E)
© ISO/ASTM International 2013

---------------------- Page: 1 ----------------------
ISO/ASTM 52628:2013(E)
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance withAdobe’s licensing policy, this file may be printed or viewed but
shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing.
In downloading this file, parties accept therein the responsibility of not infringing Adobe’s licensing policy. Neither the ISO Central
Secretariat nor ASTM International accepts any liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies
andASTM members. In the unlikely event that a problem relating to it is found, please inform the ISO Central Secretariat orASTM
International at the addresses given below.
© ISO/ASTM International 2013
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or
mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISO’s member body in the
country of the requester. In the United States, such requests should be sent to ASTM International.
ISO copyright office ASTM International,100 Barr Harbor Drive, PO Box C700,
Case postale 56 • CH-1211 Geneva 20 West Conshohocken, PA 19428-2959, USA
Tel. [phone] Tel. [phone]
Fax [phone] Fax [phone]
E-mail [e-mail] E-mail [e-mail]
Web www.iso.org Web www.astm.org
Published in Switzerland
ii © ISO/ASTM International 2013 – All rights reserved

---------------------- Page: 2 ----------------------
ISO/ASTM 52628:2013(E)
Contents Page
1 Scope. 2
2 Reference documents. 2
3 Terminology. 3
4 Significance and use. 4
5 Dosimetry system requirements. 4
6 Classification. 4
7 Guidance. 6
8 Keywords. 8
Annex. 9
Table 1 Examples of type I dosimeters. 5
Table 2 Examples of type II dosimeters. 6
Table 3 General dosimetry requirements for all radiation applications. 6
Table 4 Dosimetry requirements for specific radiation applications. 6
Table 5 Guidance for dosimetry in specific radiation applications. 7
Table 6 Guidance on absorbed-dose mapping and mathematical methods. 7
Table A1.1 Summary of characteristics of dosimeters described in ASTM and ISO/ASTM
radiation processing standards. 10
© ISO/ASTM International 2013 – All rights reserved iii

---------------------- Page: 3 ----------------------
ISO/ASTM 52628:2013(E)
Foreword
ISO(theInternationalOrganizationforStandardization)isaworldwidefederationofnationalstandardsbodies
(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 represented 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 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.
ASTM International is one of the world’s largest voluntary standards development organizations with global
participation from affected stakeholders. ASTM technical committees follow rigorous due process balloting
procedures.
A pilot project between ISO and ASTM International has been formed to develop and maintain a group of
ISO/ASTM radiation processing dosimetry standards. Under this pilot project, ASTM Committee E61,
RadiationProcessing,isresponsibleforthedevelopmentandmaintenanceofthesedosimetrystandardswith
unrestricted participation and input from appropriate ISO member bodies.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. Neither ISO nor ASTM International shall be held responsible for identifying any or all such patent
rights.
International Standard ISO/ASTM 52628 was developed by ASTM Committee E61, Radiation Processing,
through Subcommittee E61.01, on Dosimetry, and by Technical Committee ISO/TC 85, Nuclear energy,
nuclear technologies and radiological protection.
This first edition of ISO/ASTM 52628 cancels and replaces ASTM E2628-09ε1.
iv © ISO/ASTM International 2013 – All rights reserved

---------------------- Page: 4 ----------------------
ISO/ASTM 52628:2013(E)
An American National Standard
Standard Practice for
1
Dosimetry in Radiation Processing
This standard is issued under the fixed designation ISO/ASTM 52628; the number immediately following the designation indicates the
year of original adoption or, in the case of revision, the year of last revision.
INTRODUCTION
The use of ionizing radiation for the treatment of commercial products such as the sterilization of
medical devices, the reduction of microbial contamination in food or the modification of polymers is
referred to as radiation processing. The types of radiation used may be gamma radiation (typically
from cobalt-60 sources), X-radiation or accelerated electrons.
It is necessary to ensure that the specified absorbed dose is applied in each of the radiation
processing applications. The absorbed dose must be measured, and measurement systems have been
developed for this purpose. Much of the development of these systems rests on the early development
of dosimetry systems for personnel radiation protection and for medical treatment. However, the
absorbed doses used in radiation processing are generally higher, ranging from ~10 Gy up to 100 kGy
or more and new dosimetry systems have been developed for measurements of these doses.
Note that the terms “dose” and “absorbed dose” are used interchangeably in this standard (see
3.1.1).
The dose measurements required in radiation processing concern characterization of radiation
facilities in installation qualification (IQ) and operational qualification (OQ), measurement of dose
distribution in irradiated products in performance qualification (PQ) and routine monitoring of the
irradiation process.
The literature is abundant with articles on dosimeters for radiation processing, and guidelines and
standards have been written by several organizations (the International Atomic Energy Agency
(IAEA) and the International Commission on Radiation Units and Measurements (ICRU), for
example) for the operation of the dosimetry systems and for their use in the characterization and
validationoftheradiationprocessingapplications.Inparticular,ICRUReport80providesinformation
on the scientific basis and historical development of many of the systems in current use.
ASTM Subcommittee E10.01 on Radiation Processing: Dosimetry andApplications was formed in
1984 initially with the scope of developing standards for food irradiation, but its scope was widened
to include all radiation processing applications.The subcommittee, now Committee E61, has under its
jurisdiction approximately 30 standard practices and standard guides, collectively known as the E61
standards on radiation processing. A number of these standards have been published as ISO/ASTM
standards, thereby ensuring a wider international acceptance. These practices and guides describe the
dosimetry systems most commonly used in radiation processing, and the dose measurements that are
required in the validation and routine monitoring of the radiation processes. A current list of the E61
standards on radiation processing is given in 2.1 and 2.2.
The development, validation and routine control of a radiation process comprises a number of
activities, most of which rely on the ability to measure the delivered dose accurately. It is therefore
necessary that dose is measured with traceability to national, or international, standards, and the
uncertainty is known, including the effect of influence quantities. The E61 standards on radiation
processing dosimetry serve to fulfill these requirements.
The practices describing dosimetry systems have several common attributes, and there is a need to
have one general standard that can act as a common reference and that can be used as a basis for the
selection of dosimetry systems for defined tasks. ISO/ASTM Practice 52628 serves this purpose. It
outlines general requirements for the calibration and use of dosimetry systems and for the estimation
of measurement uncertainties. Details relating to each dosimetry system are found in the respective
standards and each of these refer to ISO/ASTM Practice 52628 for the general requirements.
© ISO/ASTM International 2013 – All rights reserved
1

---------------------- Page: 5 ----------------------
ISO/ASTM 52628:2013(E)
1. Scope F1736 Guide for Irradiation of Finfish and Aquatic Inverte-
brates Used as Food to Control Pathogens and Spoilage
1.1 Thispracticedescribesthebasicrequirementsthatapply
Microorganisms
when making absorbed dose measurements in accordance with
F1885 Guide for Irradiation of Dried Spices, Herbs, and
the ASTM E61 series of dosimetry standards. In addition, it
Vegetable Seasonings to Control Pathogens and Other
provides guidance on the selection of dosimetry systems and
Microorganisms
directs the user to other standards that provide specific infor-
mation on individual dosimetry systems, calibration methods, 2
2.2 ISO/ASTM Standards:
uncertainty estimation and radiation processing applications.
51205 Practice for Use of a Ceric-Cerous Sulfate Dosimetry
1.2 This practice applies to dosimetry for radiation process-
System
ing applications using electrons or photons (gamma- or
51261 Practice for Calibration of Routine Dosimetry Sys-
X-radiation).
tems for Radiation Processing
51275 Practice for Use of a Radiochromic Film Dosimetry
1.3 This practice addresses the minimum requirements of a
System
measurement management system,butdoesnotincludegeneral
51276 Practice for Use of a Polymethylmethacrylate Dosim-
quality system requirements.
etry System
1.4 This practice does not address personnel dosimetry or
51310 Practice for Use of a Radiochromic Optical Wave-
medical dosimetry.
guide Dosimetry System
1.5 This practice does not apply to primary standard dosim-
51401 Practice for Use of a Dichromatic Dosimetry System
etry systems.
51431 Practice for Dosimetry in Electron Beam and X-Ray
1.6 This standard does not purport to address all of the
(Bremsstrahlung) Irradiation Facilities for Food Process-
safety concerns, if any, associated with its use. It is the
ing
responsibility of the user of this standard to establish appro-
51538 Practice for Use of the Ethanol-Chlorobenzene Do-
priate safety and health practices and determine the applica-
simetry System
bility of regulatory limitations prior to use.
51540 Practice for Use of a Radiochromic Liquid Dosimetry
System
2. Reference documents
51607 Practice for Use of the Alanine-EPR Dosimetry Sys-
2
2.1 ASTM Standards:
tem
E170 Terminology Relating to Radiation Measurements and
51608 Practice for Dosimetry in an X-Ray (Bremsstrahlung)
Dosimetry
Facility for Radiation Processing
E1026 Practice for Using the Fricke Dosimetry System
51631 Practice for Use of Calorimetric Dosimetry Systems
E2232 Guide for Selection and Use of Mathematical Meth-
for Electron Beam Dose Measurements and Routine
ods for Calculating Absorbed Dose in Radiation Process-
Dosimeter Calibration
ing Applications
51649 Practice for Dosimetry in an Electron-Beam Facility
E2303 Guide for Absorbed-Dose Mapping in Radiation
for Radiation Processing at Energies Between 300 keV
Processing Facilities
and 25 MeV
E2304 Practice for Use of a LiF Photo-Fluorescent Film
51650 Practice for Use of a Cellulose Triacetate Dosimetry
Dosimetry System
System
E2381 Guide for Dosimetry In Radiation Processing of
51702 Practice for Dosimetry in a Gamma Facility for
Fluidized Beds and Fluid Streams
Radiation Processing
E2449 Guide for Irradiation of Pre-packaged Processed
Meat and Poultry Products to Control Pathogens and 51707 Guide for Estimating Uncertainties in Dosimetry for
Other Microorganisms Radiation Processing
F1355 GuideforIrradiationofFreshAgriculturalProduceas
51818 Practice for Dosimetry in an Electron Beam Facility
a Phytosanitary Treatment
for Radiation Processing at Energies Between 80 and 300
F1356 PracticeforIrradiationofFreshandFrozenRedMeat
keV
and Poultry to Control Pathogens and Other Microorgan-
51900 Guide for Dosimetry in Radiation Research on Food
isms
and Agricultural Products
51939 Practice for Blood Irradiation Dosimetry
51940 Guide for Dosimetry for Sterile Insect Release
1
This practice is under the jurisdiction of ASTM Committee E61 on Radiation
Programs
Processing and is the direct responsibility of Subcommittee E61.01 on Dosimetry,
and is also under the jurisdiction of ISO/TC 85/WG 3. 51956 Practice for Thermoluminescence-Dosimetry (TLD)
Current edition approved July 20, 2013. Published November 2013. Originally
Systems for Radiation Processing
ε1
published as ASTM E2628–09. Last previous ASTM edition E2628–09 . The
52116 Practice for Dosimetry for a Self-Contained Dry-
present International Standard ISO/ASTM 52628–2013(E) replaces ASTM
ε1
E2628–09 . Storage Gamma Irradiator
2
For referenced ASTM and ISO/ASTM standards, visit the ASTM website,
52701 Guide for Performance Characterization of Dosim-
www.astm.org, or contact ASTM Customer Service at [e-mail]. For
eters and Dosimetry Systems for Use in Radiation Pro-
Annual Book of ASTM Standards volume information, refer to the standard’s
Document Summary page on the ASTM website. cessing
© ISO/ASTM International 2013 – All rights reserved
2

---------------------- Page: 6 ----------------------
ISO/ASTM 52628:2013(E)
3
2.3 ISO Standards: 3.1.4 dosimeter—device that, when irradiated, exhibits a
ISO 11137-1 Sterilization of health care products – Radia- quantifiable change that can be related to absorbed dose in a
tion – Part 1: Requirements for development, validation given material using appropriate measurement instruments and
and routine control of a sterilization process for medical procedures.
devices
3.1.5 dosimeter/dosimetry system characterization
ISO 11137-3 Sterilization of health care products – Radia-
—determination of performance characteristics, such as dose
tion – Part 3: Guidance on dosimetric aspects
range, reproducibility and the effect of influence quantities, for
ISO 10012 Measurement managements systems – Require-
a dosimeter/dosimetry system under defined test conditions.
ments for measurement processes and measuring equip-
3.1.6 dosimeter response —reproducible, quantifiable effect
ment
produced in the dosimeter by ionizing radiation.
ISO/IEC 17025 General requirements for the competence of
3.1.6.1 Discussion—The dosimeter response value, ob-
testing and calibration laboratories
tained from one or more measurements, is used in the estima-
2.4 International Commission on Radiation Units and Mea-
tion of the derived absorbed dose. The response value may be
4
surements (ICRU) Reports:
obtained from such measurements as optical absorbance,
ICRU Report 80 Dosimetry Systems for Use in Radiation
thickness, mass peak-to-peak distance in EPR spectra, or
Processing
electropotential between solutions.
ICRU Report 85a Fundamental Quantities and Units for
3.1.7 dosimetry—measurement of absorbed dose by the use
Ionizing Radiation
of a dosimetry system.
2.5 Joint Committee for Guides in Metrology (JCGM)
3.1.8 dosimetry system—system used for measuring ab-
Reports:
sorbed dose, consisting of dosimeters, measurement instru-
JCGM 100:2008, GUM , 1995, with minor corrections,
ments and their associated reference standards, and procedures
Evaluation of measurement data – Guide to the Expres-
5
for the system’s use.
sion of Uncertainty in Measurement
JCGM 100:2008, VIM , International vocabulary of metrol-
3.1.9 influence quantity—quantity that, in a direct
6
ogy – basis and general concepts and associated terms
measurement, does not affect the quantity that is actually
measured, but affects the relation between the indication and
3. Terminology
the measurement result. VIM
3.1 Definitions:
3.1.10 measurement management system—set of interre-
3.1.1 absorbed dose (D)—quotient of dε¯ by dm, where dε¯ is
lated or interacting elements necessary to achieve metrological
the mean energy imparted by ionizing radiation to matter of
confirmation and continual control of measurement processes.
mass dm, thus
3.1.11 primary standard dosimetry system —dosimetry sys-
D 5 dε¯⁄dm
tem that is designated or widely acknowledged as having the
ICRU 85a
highest metrological qualities and whose value is accepted
without reference to other standards of the same quantity.
3.1.1.1 Discussion—TheSIunitofabsorbeddoseisthegray
(Gy),where1grayisequivalenttotheabsorptionof1jouleper 3.1.12 radiation processing—intentionalirradiationofprod-
kilogram of the specified material (1 Gy = 1 J/kg).
ucts or materials to preserve, modify or improve their charac-
3.1.2 accredited dosimetry calibration laboratory— teristics.
dosimetry laboratory with formal recognition by an accrediting
3.1.13 reference standard dosimetry system—dosimetry
organization that the dosimetry laboratory is competent to
system, generally having the highest metrological quality
carry out specific activities which lead to the calibration or
available at a given location or in a given organization, from
calibration verification of dosimetry systems in accordance
which measurements made there are derived.
with documented requirements of the accrediting organization.
3.1.14 reference standard radiation field—calibrated radia-
3.1.3 calibration—set of operations that establish, under
tion field, generally having the highest metrological quality
specified conditions, the relationship between values of quan-
available at a given location or in a given organization, from
tities indicated by a measuring instrument or measuring
which measurements made there are derived.
system, or values represented by a material measure or a
3.1.15 response function—mathematical representation of
reference material, and the corresponding values realized by
therelationshipbetweendosimeterresponseandabsorbeddose
standards.
for a given dosimetry system.
3.1.16 routine dosimetry system—dosimetry system cali-
3
Available from International Organization for Standardization (ISO), 1, ch. de
brated against a reference standard dosimetry system and used
la Voie-Creuse, Case postale 56, CH-1211, Geneva 20, Switzerland, http://
www.iso.ch.
for routine absorbed dose measurements, including dose map-
4
Available from the International Commission on Radiation Units and
ping and process monitoring.
Measurements, 7910 Woodmont Ave, Suite 800, Bethesda, MD 20815, USA.
5
3.1.17 traceability—property of the result of a measurement
Document produced by Working Group 1 of the Joint Committee for Guides in
Metrology (JCGM/WG 1). Available free of charge at the BIPM website (http://
or the value of a standard whereby it can be related to stated
www.bipm.org).
references, usually national or international standards, through
6
Document produced by Working Group 2 of the Joint Committee for Guides in
an unbroken chain of comparisons all having stated uncertain-
Metrology (JCGM/WG 2). Available free of charge at the BIPM website (http://
www.bipm.org). ties.
© ISO/ASTM International 2013 – All rights reserved
3

---------------------- Page: 7 ----------------------
ISO/ASTM 52628:2013(E)
3.1.18 transfer standard dosimetry system—dosimetry sys- 5.1.1 Theselectionanduseofaspecificdosimetrysystemin
tem used as an intermediary to calibrate other dosimetry agivenapplicationshallbejustifiedtakingintoaccountatleast
systems. the following:
dose range
3.1.19 type I dosimeter—dosimeter of high metrological
radiation type
quality, the response of which is affected by individual influ-
effect of influence quantities
ence quantities in a well-defined way that can be expressed in
required level of uncertainty
terms of independent correction factors.
required spatial resolution
3.1.19.1 Discussion—See Section 6 for examples and fur-
5.1.2 The dosimetry system shall be calibrated in accor-
ther details.
dance with the requirements of ISO/ASTM Practice 51261.
3.1.20 type II dosimeter—dosimeter, the response of which
5.1.3 The uncertainty associated with measurements made
isaffectedbyinfluencequantitiesinacomplexwaythatcannot
with the dosimetry system shall be established and docu-
practically be expressed in terms of independent correction
mented. All dose measurements shall be accompanied by an
factors.
estimate of uncertainty. See ISO/ASTM 51707, GUM and
7
NIST Technical Note 1297 for guidance.
3.1.20.1 Discussion—See Section 6 for examples and fur-
ther details. 5.1.4 Documentation shall be established and maintained to
ensurecompliancewiththeminimumrequirementsspecifiedin
3.1.21 uncertainty—parameter associated with the result of
the ASTM or ISO/ASTM standard relevant to the specific
a measurement that characterizes the dispersion of the values
dosimetry system. The user’s quality system might be more
that could reasonably be attributed to the measurand or derived
detailed than these minimum requirements.
quantity.
3.1.22 uncertainty budget—quantitative analysis of the 6. Classification
component terms contributing to the uncertainty of a
6.1 Classification of dosimeters and dosimetry systems in
measurement, including their statistical distribution, math-
the ASTM E61 series of dosimetry standards is based on two
ematical manipulation and summation.
distinct criteria: (1) the inherent metrological properties of the
dosimeter (see 3.1.19 and 3.1.20), and (2) the field of applica-
3.2 Definitions of other terms used in this standard that
tion of the dosimetry system (see 3.1.13 and 3.1.16). These
pertain to radiation measurement and dosimetry may be found
classifications are important in both the selection and calibra-
in ASTM Terminology E170. Definitions in ASTM E170 are
tion of dosimetry systems.
compatible with ICRU Report 85a; that document, therefore,
may be used as an alternative reference. Where appropriate,
NOTE 1—Type I and type II dosimeter classification (see 6.2) and the
definitions used in this standard have been derived from, and
classification of dosimetry systems (see 6.3) are an extension to the
classifications identified in ISO/ASTM Practice 51261. The examples
are consistent with, general metrological definitions given in
showninISO/ASTM51261listdosimetersusedinreferencestandardand
the VIM.
routine applications but do not distinguish between the dosimeter and the
system in which it is used. The classification used in this standard will be
4. Significance and use
incorporated in all subsequent revisions of the ASTM E61 series of
dosimetry standards.
4.1 Radiation processing of articles in both commercial and
6.2 Classification of Dosimeters Based on Metrological
research applications may be carried out for a number of
Properties:
purposes. These include, for example, sterilization of health
6.2.1 This classification of dosimeters is based on knowl-
care products, reduction of the microbial populations in foods
edge of their inherent metrological properties. The method of
and modification of polymers. The radiations used may be
measurement may be important in the classification (see
accelerated electrons, gamma-radiation from radionuclide
below), but the classification does not include consideration of
sources such as cobalt-60, or X-radiation.
the actual instrumentation used, or the quality of preparation
4.2 To demonstrate control of the radiation process, the
(manufacture) of the dosimeter. For example, acidic solutions
absorbed dose must be measured using a dosimetry system, the
of dichromate ions have certain inherent properties in terms of
calibration of which, is traceable to appropriate national or
their response to radiation and the effect of irradiation tem-
international standards. The radiation-induced change in the
perature that mean they are classified as type I dosimeters. The
dosimeter is evaluated and related to absorbed dose through
actual performance of a given dosimetry system based on
calibration. Dose measurements required for particular pro-
dichromate dosimeters will depend, however, on the quality of
cesses are described in other standards referenced in this
preparation of the dosimetric solution and the quality of the
practice.
spectrophotometers used for optical absorbance measurement.
6.2.2 Knowledge of the inherent properties of a dosimeter is
5. Dosimetry system requirements
important when selecting a dosimeter for a particular applica-
tion. For example, when selecting a dosimeter to be used to
5.1 Dosimetrysystemrequirementsareanecessarypartofa
measurement management system.The following requirements
shall be included as a minimum, but additional requirements
7
Taylor, B. N., and Kuyatt, C. E., “Guidelines for Evaluating and Expressing the
may be appropriate depending on the nature of the process.
Uncertainty of NIST Measurement Results,” NIST TN-1297, Gaithersburg, MD:
Guidance on these requirements is given in Section 7. NIST 1994.
© ISO/ASTM International 2013 – All rights reserved
4

---------------------- Page: 8 ----------------------
ISO/ASTM 52628:2013(E)
transferdosebetweenradiationfieldsofdifferingtemperatures, national standards laboratory or an accredited dosimetry cali-
it is essential to choose a dosimeter whose response can be bration laboratory. In the case of transfer standard dosimetry
correctedfortheeffectofirradiationtemperature,thatis,a type
systems, dosimeters are sent to a facility for irradiation and
I dosimeter.
then returned to the issuing laboratory for measurement. The
6.2.3 In order for a dosimeter to be classified as a type I
requirement to transport dosimeters without unduly increasing
dosimeter, it must be possible to apply accurate, independent,
measurement uncertainty restricts the type of dosimeter that
corrections to its response to account for the effects of relevant
can be used. Alanine/EPR, dichromate or ceric-cerous dosim-
influence quantities, such as temperature, dose rate, etc. The
etry systems are commonly used in this way.
magnitude of the correction, the range of values of the
6.3.1.3 A reference standard dosimetry system comprises
influence quantity over which it is applicable and the range of
dosimeters and the associated measurement equipment and
doses over which it is applicable are determined as part of
quality system documentation necessary to ensure traceability
dosimeter characterization (see 7.3). In classifying a dosimeter
to appropriate national and international standards. The dosim-
asa type I dosimeter,itmaybenecessarytospecifythemethod
eter used in a reference standard dosimetry system is generally
of measurement. For example, free radicals produced in
a type I dosimeter, although there may be exceptions (see, for
irradiated alanine can, in principle, be measured by a number
example, ISO/ASTM 51631).
of different techniques, however, only the EPR technique has
6.3.1.4 The expanded uncertainty achievable with measure-
beenshowntoprovidethehighmetrologicalquality(accuracy)
ments made using a reference standard dosimetry system is
necessarytoclassifyalanineasa type I dosimeter.Examplesof
typically of the order of 63%(k=2). In certain specific
type I dosimeters are given in Table 1.
6.2.4 The classification of a dosimeter as a type II dosimeter applications, for example the use of electrons of energy below
is based on the complexity of interaction between influence 1 MeV, practical limitations of the techniques may mean that
quantities, such as temperature and dose rate, which makes it
th
...