ISO/ASTM 51607:2013

Practice for use of the alanine-EPR dosimetry system

ISO/ASTM 51607:2013 covers dosimeter materials, instrumentation, and procedures for using the alanine-EPR dosimetry system for measuring the absorbed dose in the photon and electron radiation processing of materials. The system is based on electron paramagnetic resonance (EPR) spectroscopy of free radicals derived from the amino acid alanine. The alanine dosimeter is classified as a type I dosimeter as it is affected by individual influence quantities in a welldefined way that can be expressed in terms of independent correction factors. The alanine dosimeter may be used in either a reference standard dosimetry system or in a routine dosimetry system. ISO/ASTM 51607:2013 is one of a set of standards that provides recommendations for properly implementing dosimetry in radiation processing, and describes a means of achieving compliance with the requirements of ASTM E2628 for alanine dosimetry system. It is intended to be read in conjunction with ASTM E2628.

Pratique de l'utilisation d'un système dosimétrique à l'alanine utilisant la résonance paramagnétique électronique

General Information

• Status: Published
• Publication Date: 14-May-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
• Start Date: 04-Apr-2025
• Completion Date: 30-Oct-2025

Relations

• Revises: ISO/ASTM 51607:2004 - Practice for use of the alanine-EPR dosimetry system
• Effective Date: 20-Oct-2012

Standards Content (Sample)

INTERNATIONAL ISO/ASTM
STANDARD 51607
Third edition
2013-06-01
Practice for use of an alanine-EPR
dosimetry system
Pratique pour l’utilisation d’un système dosimétrique à l’alanine
utilisant la résonance paramagnétique électronique
Reference number
© ISO/ASTM International 2013
© ISO/ASTM International 2013
Allrightsreserved.Unlessotherwisespecified,nopartofthispublicationmaybereproducedorutilizedinanyformorbyanymeans,electronicormechanical,
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
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Published in Switzerland
ii © ISO/ASTM International 2013 – All rights reserved

ISO/ASTM51607:2013(E)
Contents Page
1 Scope . 1
2 Referenced documents . 1
3 Terminology . 1
4 Significance and use . 2
5 Overview . 2
6 Influence quantities . 2
7 Dosimetry system and its verification . 3
8 Incoming dosimeter stock assessment . 4
9 Calibration procedures . 4
10 Routine use . 4
11 Minimum documentation requirements . 5
12 Measurement uncertainty . 5
13 Keywords . 5
Bibliography . 5
© ISO/ASTM International 2013 – All rights reserved iii

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,
Radiation Processing, is responsible for the development and maintenance of these dosimetry standards with
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 51607 was developed by ASTM Committee E61, Radiation Processing,
through Subcommittee E61.02, Dosimetry Systems, and byTechnical Committee ISO/TC 85, Nuclear energy,
nuclear technologies and radiological protection.
This third edition of ISO/ASTM 51607 cancels and replaces ISO/ASTM 51607:2004(E)
iv © ISO/ASTM International 2013 – All rights reserved

An American National Standard
Standard Practice for
Use of an Alanine-EPR Dosimetry System
This standard is issued under the fixed designation ISO/ASTM 51607; 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 2. Referenced documents
1.1 This practice covers dosimeter materials, instrumenta- 2.1 ASTM Standards:
tion, and procedures for using the alanine-EPR dosimetry E170 TerminologyRelatingtoRadiationMeasurementsand
system for measuring the absorbed dose in the photon and Dosimetry
electron radiation processing of materials.The system is based E2628 Practice for Dosimetry in Radiation Processing
on electron paramagnetic resonance (EPR) spectroscopy of E2701 Guide for Performance Characterization of Dosim-
free radicals derived from the amino acid alanine. etersandDosimetrySystemsforUseinRadiationProcess-
1.2 The alanine dosimeter is classified as a type I dosimeter ing
as it is affected by individual influence quantities in a well- 2.2 ISO/ASTM Standards:
defined way that can be expressed in terms of independent 51261 Practice for Calibration of Routine Dosimetry Sys-
correction factors (see ASTM Practice E2628). The alanine tems for Radiation Processing
dosimetermaybeusedineitherareferencestandarddosimetry 51707 Guide for Estimating Uncertainties in Dosimetry for
system or in a routine dosimetry system. Radiation Processing
1.3 This document is one of a set of standards that provides 2.3 ICRU Reports:
recommendations for properly implementing dosimetry in ICRU Report 85a Fundamental Quantities and Units for
radiation processing, and describes a means of achieving Ionizing Radiation
compliance with the requirements of ASTM E2628 “Practice ICRU Report 80 Dosimetry Systems for Use in Radiation
for Dosimetry in Radiation Processing” for alanine dosimetry Processing
system. It should be read in conjunction with ASTM E2628. 2.4 Joint Committee for Guides in Metrology (JCGM)
1.4 Thispracticecoversalanine-EPRdosimetrysystemsfor Reports:
dose measurements under the following conditions: JCGM 100:2008, GUM 1995, with minor corrections,
1.4.1 The absorbed dose range is between 1 and 1.5 3 Evaluation of measurement data – Guide to the Expres-
10 Gy. sion of Uncertainty in Measurement
2 -1
1.4.2 The absorbed dose rate is up to 10 Gy s for continu- JCGM100:2008,VIM ,Internationalvocabularyofmetrol-
10 -1
ous radiation fields and up to 3 3 10 Gy s for pulsed ogy – Basis and general concepts and associated terms
radiation fields (1-4).
3. Terminology
1.4.3 The radiation energy for photons and electrons is
between 0.1 and 30 MeV (1, 2, 5-8). 3.1 Definitions:
3.1.1 alanine dosimeter—specified quantity and physical
1.4.4 The irradiation temperature is between –78 °C and +
70 °C (2, 9-12). form of the radiation-sensitive material alanine and any added
1.5 This standard does not purport to address all of the inert substance such as a binder.
3.1.2 alanine-EPR dosimetry system—system used for de-
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- termining absorbed dose, consisting of alanine dosimeters, an
EPR spectrometer and its associated reference materials, and
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. procedures for the system’s use.
This practice is under the jurisdiction of ASTM Committee E61 on Radiation
Processing and is the direct responsibility of Subcommittee E61.02 on Dosimetry For referenced ASTM and ISO/ASTM standards, visit the ASTM website,
Systems, and is also under the jurisdiction of ISO/TC 85/WG 3. www.astm.org, or contact ASTM Customer Service at [e-mail]. For
Current edition approved April 9, 2013. Published June 2013. Originally Annual Book of ASTM Standards volume information, refer to the standard’s
ϵ1
published as ASTM E1607–94. Last previous ASTM edition E1607–96 . Document Summary page on the ASTM website.
ASTM E1607–94 was adopted by ISO in 1998 with the intermediate designation Available from International Commission on Radiation Units and Measure-
ISO 15566:1998(E).The present International Standard ISO/ASTM 51607:2013(E) ments, 7910 Woodmont Ave., Suite 800, Bethesda, MD 20814, U.S.A.
replaces ISO 15566 and is a major revision of the last previous edition ISO/ASTM DocumentproducedbyWorkingGroup1oftheJointCommitteeforGuidesin
51607–2004(E). Metrology (JCGM/WG 1). Available free of charge at the BIPM website (http://
The term “electron spin resonance” (ESR) is used interchangeably with www.bipm.org).
electron paramagnetic resonance (EPR). DocumentproducedbyWorkingGroup2oftheJointCommitteeforGuidesin
Theboldfacenumbersinparenthesesrefertothebibliographyattheendofthis Metrology (JCGM/WG 2). Available free of charge at the BIPM website (http://
standard. www.bipm.org).
© ISO/ASTM International 2013 – All rights reserved
3.1.3 alanine-EPR dosimeter response—value resulting 5.4 The dosimeter contains crystalline alanine and registers
from applied adjustments to the EPR signal amplitude. the absorbed dose by the formation of alanine-derived free
radicals (22). Identification and measurement of alanine-
3.1.4 check standard—astandardpreparedindependentlyof
the calibration standards that is measured to verify the perfor- derived free radicals are performed by EPR spectroscopy.
ICRU Report 80 provides information on the scientific basis
mance of a dosimetry system.
and historical development of this dosimetry system.
3.1.5 EPR intensity reference material—a stable paramag-
5.5 The measurement of free radicals by EPR spectroscopy
netic material whose measurement by EPR is applied to the
is nondestructive. This can be repeated and hence can be used
dosimeter EPR signal amplitude as part of the dosimeter
for archival purposes (23-25).
response determination.
3.1.6 EPR signal amplitude—peak-to-peakamplitudeofthe
6. Influence quantities
central signal of the EPR spectrum.
6.1 Factors other than absorbed dose which influence the
3.1.6.1 Discussion—This signal is proportional to the
dosimeter response are referred to as influence quantities, and
alanine-derived free radical concentration in the alanine do-
are discussed in the following sections (see alsoASTM Guide
simeter.
E2701).Examplesofsuchinfluencequantitiesaretemperature
3.1.7 EPR spectroscopy—measurement of resonant absorp-
and dose rate.
tion of electromagnetic energy resulting from the transition of
6.2 Pre-Irradiation Conditions:
unpaired electrons between different energy levels, upon ap-
6.2.1 Dosimeter Conditioning and Packaging—Alaninedo-
plication of radio frequencies to a paramagnetic substance in
simeter conditioning and packaging may be important under
the presence of a magnetic field.
certain conditions (see 6.2.4).
3.1.8 EPR spectrum—first derivative of the electron para-
magnetic absorption spectrum measured as a function of the
NOTE 2—Thesortingofalaninepelletdosimetersbymassintosub-lots
magnetic field. will improve the measurement uncertainty.
3.1.9 zero dose amplitude—EPR signal amplitude of an
6.2.2 Time Since Manufacture—There is no known influ-
unirradiated alanine dosimeter with the same EPR spectrom-
ence of time since manufacture on alanine dosimeters when
eter parameters used for the lowest measurable absorbed dose
stored under recommended conditions.
value.
6.2.3 Temperature—There is no known influence of pre-
3.2 Definitions of other terms used in this standard that
irradiation temperature. However, it is recommended that
pertain to radiation measurement and dosimetry may be found
alanine dosimeters be stored at manufacturer recommended
inASTM Terminology E170. Definitions in E170 are compat-
temperatures. Exposure to temperatures outside the manufac-
ible with ICRU Report 85a; that document, therefore, may be
turer’s recommended range should be avoided to reduce the
used as an alternative reference.
potential for adverse effects on dosimeter response.
6.2.4 Relative Humidity—The humidity during pre-
4. Significance and use
irradiation storage may influence the EPR signal amplitude of
alanine dosimeters (24, 25). The effect of humidity may be
4.1 The alanine-EPR dosimetry system provides a means
reduced by sealing dosimeters in a material impervious to
formeasuringabsorbeddose.Itisbasedonthemeasurementof
water.
specific stable free radicals in crystalline alanine generated by
6.2.5 Exposure to Light—There is no known influence of
ionizing radiation.
ambient light.
4.2 Alanine-EPR dosimetry systems are used in reference-
6.3 Conditions During Irradiation:
or transfer-standard or routine dosimetry systems in radiation
6.3.1 Irradiation Temperature—Theirradiationtemperature
applications that include: sterilization of medical devices and
influences the EPR signal amplitude of alanine dosimeters.
pharmaceuticals, food irradiation, polymer modifications,
medical therapy and radiation damage studies in materials (1,
NOTE 3—The effect of irradiation temperature on the dosimeter EPR
13-15).
signal amplitude may be dependent on the dosimeter type. The tempera-
-1
ture coefficient, R (K ) is described by the relationship, (∆m/m)/∆T,
t
where m is the EPR signal amplitude (in arbitrary units) and T is the
5. Overview
irradiation temperature (in K). For dosimeters with L-alanine, a positive
5.1 The dosimeter is prepared using α-alanine, CH -
temperature coefficient, expressed in percent, in the range of +0.1 to
-1
CH(NH )-COOH, in the form of polycrystalline powder.
2 +0.2% °C is typical for irradiation temperatures from –10 °C to +70 °C
5.2 All stereoisomers of α-alanine are suitable for dosim- (10, 11, 26-28);refertoRef (9, 12)forirradiationtemperaturesbelow–10
°C. The temperature coefficient for dosimeters prepared with the DL
etry; L-alanine is used most commonly.
stereoisomer of alanine is more than 50% higher than one prepared with
5.3 Usual physical shapes are films or pellets (cylinders).
L-alanine (29). A summary of published temperature coefficients is
NOTE 1—Additives, capsules, or film support materials used in the tabulated in Ref (26, 29).
preparation of dosimeters should not add any significant intrinsic or
6.3.2 Absorbed-Dose Rate—Under normal radiation pro-
radiation-induced EPR signal. Examples of suitable binders are ethylene-
cessing conditions there is no measurable effect of absorbed
propylene rubber, gelatin, paraffin, polyethylene, polyethylene vinyl
dose rate; however, a dose dependent effect has been charac-
acetate, polystyrene, polyvinylpyrrolidone, polyvinyl propylene, and
terized for alanine dosimeters irradiated to high doses at low
stearin. Lubricants added in the dosimeter manufacturing process are
optional. An example of a suitable lubricant is stearic acid (16-21). dose rates (30).
© ISO/ASTM International 2013 – All rights reserved
NOTE 4—The dose-rate effect is absorbed-dose dependent. Alanine
6.5.1 Exposure to Light—There is no significant influence
dosimeters irradiated with gamma radiation to absorbed doses > 5 kGy at
of ambient light.
low dose rates (< 2 Gy/s) show a progressive decrease in EPR signal
6.5.2 Temperature—Controlled temperatures are recom-
amplitudes relative to that found at dose rates greater than 2 Gy/s (30).
mended for measuring alanine dosimeters. Avoid exposure to
This combined dose/dose rate effect may reach several percent and is
temperatures outside the manufacturer’s recommended range.
irradiation temperature dependent; though relatively constant above 0 °C,
no rate effect was measured at –10 °C and –40 °C (31).
6.5.3 Relative Humidity—The humidity during measure-
ment can influence the EPR signal amplitude of alanine
6.3.3 Dose Fractionation—There is no known influence of
dosimeters. During measurement, the effects of humidity can
dose fractionation.
be compensated by measuring the ratio of the alanine signal to
NOTE 5—In some instances the fractionation of dose to alanine dosim-
that of a humidity insensitive EPR intensity reference material
eters may not be straightforward. Certain influence quantities that con-
(see 7.3.1). If a humidity sensitive EPR reference material is
tribute to the dosimeter response may not be equivalent for the fraction-
used(e.g.anirradiation-calibratedalaninedosimeter)compen-
ated and non-fractionated irradiations. For example, the fractionation of
sate for changes in humidity by standardizing the time of
dose imposes multiple temperature changes to the dosimeter that may not
measurement (see 6.4.4) between the reference and dosimeter
be equivalent to the irradiation temperature experienced by a dosimeter
reading (see Note 8).
irradiatedtoasingledose(equaltothesumofthefractionateddoses).An
accurate comparison of fractionated and non-fractionated doses will
NOTE 7—Some commercial EPR instrumentation may automatically
depend greatly on an accurate knowledge of the irradiation temperature
compensate for nominal changes in temperature and ambient humidity.
for the irradiations (see 6.3.1).
NOTE 8—The historical data for humidity effects on alanine dosimeters
6.3.4 Relative Humidity—The humidity during irradiation
and quantitative EPR measurements have been compiled (25, 34-36).
mayinfluencetheEPRsignalamplitudeofalaninedosimeters.
7. Dosimetry system and its verification
The effect of humidity may be reduced by sealing dosimeters
in a material impervious to water.
7.1 The following are components of the Alanine-EPR
6.3.5 Exposure to Light—There is no known influence of
Dosimetry System:
ambient light.
7.1.1 Alanine Dosimeters.
6.3.6 Radiation Energy—For most radiation processing ap-
7.1.2 EPR Spectrometer.
plications there is no influence of radiation energy for photons
7.1.2.1 AnX-bandEPRspectrometerisusedtomeasurethe
and electrons.
EPR signal amplitude of an alanine dosimeter. To obtain the
expanded uncertainty cited in 12.3, an EPR spectrometer
NOTE 6—Differences have been reported between the absorbed dose to
water response of alanine dosimeters irradiated by photons and electrons should be capable of the following settings:
overarangeofenergies (4, 6-8).Theresponseinelectronbeamshasbeen
(1) microwave frequency 9 to 10 GHz with automatic
reported to be 1–2 % lower than in Co-60 beams (8) and the response in
frequency locking (AFC);
150 kV X-ray beams has been reported to be ~15% lower (7). The
(2) corresponding magnetic field to set a g-factor of 2.0 (at
responseto~100keVelectronswasfoundtobeequivalenttotheresponse
9.8GHz,thisequals350mT)withafieldscanrangeof20mT
to high energy electrons (32, 33).
about the center field;
6.4 Post-Irradiation Conditions:
(3) magnetic field modulation amplitude 0.1 to 1.5 mT;
6.4.1 Time—Theintervalbetweenirradiationanddosimeter
(4) microwave power 0.1 to 10 mW (leveled);
reading shall be standardized and should conform to the
(5) adjustable sweep time, time constant, and receiver gain
manufacturer’s recommendations (see 6.4.4). Alanine dosim-
according to absorbed dose.
eters are commonly regarded as stable over time periods as
7.1.2.2 Thesensitivityofthespectrometershouldbeatleast
longasweeksormonths.However,thedegreeofstabilitymay
2 3 10 spins for EPR line width of 0.1 mT (37).
be influenced by, but not limited to, absorbed dose, relative
7.1.3 Dosimeter Holder.
humidity, dosimeter composition and this should be character-
7.1.3.1 There shall be some mechanical means of position-
ized by the end user.
ingthedosimeteraccuratelyandreproducibly,intermsofboth
6.4.2 Temperature—There is no known influence of storage
vertical position and centricity in the EPR spectrometer cavity.
temperature on alanine dosimeters. However, it is recom-
The dosimeter holder is usually made of fused quartz or
mended that alanine dosimeters be stored according to manu-
suitable polymer and should be of such quality and cleanliness
facturer’s recommendations.
to contribute no interfering EPR signal.
6.4.3 Conditioning Treatment—Post-irradiationtreatmentis
7.1.4 Analytical Balance (Optional).
not applicable.
6.4.4 Storage Relative Humidity—The humidity during 7.1.4.1 For certain types of dosimeters, the measurement
reproducibility may be improved by normalizing the EPR
post-irradiationstoragecaninfluencetheEPRsignalamplitude
of
...