ISO/ASTM 51205:2017

Practice for use of a ceric-cerous sulfate dosimetry system

1.1 This practice covers the preparation, testing, and procedure for using the ceric-cerous sulfate dosimetry system to measure absorbed dose to water when exposed to ionizing radiation. The system consists of a dosimeter and appropriate analytical instrumentation. For simplicity, the system will be referred to as the ceric-cerous system. The ceric-cerous dosimeter is classified as a type 1 dosimeter on the basis of the effect of influence quantities. The ceric-cerous system may be used as a reference standard dosimetry system or as a routine dosimetry system. 1.2 ISO/ASTM 51205:2017 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 ISO/ASTM Practice 52628 for the ceric-cerous system. It is intended to be read in conjunction with ISO/ASTM Practice 52628. 1.3 This practice describes both the spectrophotometric and the potentiometric readout procedures for the ceric-cerous system. 1.4 This practice applies only to gamma radiation, X-radiation/bremsstrahlung, and high energy electrons.

Pratique de l'utilisation d'un système dosimétrique au sulfate cérique-céreux

General Information

• Status: Published
• Publication Date: 02-May-2017
• 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: 9093 - International Standard confirmed
• Completion Date: 27-Sep-2022

Relations

• Revises: ISO/ASTM 51205:2009 - Practice for use of a ceric-cerous sulfate dosimetry system
• Effective Date: 28-May-2016

Standards Content (Sample)

INTERNATIONAL ISO/ASTM
STANDARD 51205
Third edition
2017-05
Practice for use of a ceric-cerous
sulfate dosimetry system
Pratique de l’utilisation d’un système dosimétrique au sulfate
cérique-céreux
Reference number
ISO/ASTM 51205:2017(E)
©
ISO/ASTM International 2017

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ISO/ASTM 51205:2017(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO/ASTM International 2017, Published in Switzerland
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ii © ISO/ASTM International 2017 – All rights reserved

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ISO/ASTM 51205:2017(E)
Contents Page
1 Scope. 1
2 Referenced documents. 1
3 Terminology. 2
4 Significance and use. 2
5 Effect of influence quantities. 2
6 Interferences . 3
7 Apparatus. 3
8 Reagents. 3
9 Preparation of the dosimeters. 3
10 Calibration of the dosimetry system . 4
11 Application of dosimetry system . 6
12 Minimum documentation requirements. 6
13 Measurement uncertainty. 6
14 Keywords. 7
Annexes. 7
Figure A1.1 Electrochemical cell. 7
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ISO/ASTM 51205:2017(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.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of
ISO documents should be noted. International Standards are drafted in accordance with the editorial rules of
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
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.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO and ASTM International shall not be held responsible for identifying any or all such patent rights.
DetailsofanypatentrightsidentifiedduringthedevelopmentofthedocumentwillbeintheIntroductionand/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO’s adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following URL: www.iso.org/
iso/foreword.html.
This document was prepared by ASTM Committee E61 Radiation Processing and by Technical Committee
ISO/TC 85, nuclear energy, nuclear technologies and radiological protection.
This third edition cancels and replaces the second edition (ISO/ASTM 51205:2009), which has been
technically revised.
iv © ISO/ASTM International 2017 – All rights reserved

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This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
ISO/ASTM 51205:2017(E)
Standard Practice for
1
Use of a Ceric-Cerous Sulfate Dosimetry System
This standard is issued under the fixed designation ISO/ASTM 51205; the number immediately following the designation indicates the
year of original adoption or, in the case of revision, the year of last revision.
NOTE 1—The lower energy limits are appropriate for a cylindrical
1. Scope
dosimeter ampoule of 12-mm diameter. Corrections for dose gradient
1.1 This practice covers the preparation, testing, and proce-
across the ampoule may be required for electron beams (2). The
dure for using the ceric-cerous sulfate dosimetry system to
ceric-cerous system may be used at lower energies by employing thinner
(in the beam direction) dosimeters (see ICRU Report 35).
measure absorbed dose to water when exposed to ionizing
radiation. The system consists of a dosimeter and appropriate
1.5.4 The irradiation temperature of the dosimeter is above
analytical instrumentation. For simplicity, the system will be
0°C and below 62°C (3).
referred to as the ceric-cerous system.The ceric-cerous dosim-
NOTE 2—The temperature coefficient of dosimeter response is known
eter is classified as a type 1 dosimeter on the basis of the effect
only in this range (see 5.2). Use outside this range requires determination
ofinfluencequantities.Theceric-ceroussystemmaybeusedas
of the temperature coefficient.
a reference standard dosimetry system or as a routine dosim-
1.6 This standard does not purport to address all of the
etry system.
safety concerns, if any, associated with its use. It is the
1.2 This document is one of a set of standards that provides responsibility of the user of this standard to establish appro-
recommendations for properly implementing dosimetry in priate safety and health practices and determine the applica-
radiation processing, and describes a means of achieving
bility of regulatory limitations prior to use.
compliance with the requirements of ISO/ASTM Practice 1.7 This international standard was developed in accor-
52628 for the ceric-cerous system. It is intended to be read in
dance with internationally recognized principles on standard-
conjunction with ISO/ASTM Practice 52628. ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
1.3 This practice describes both the spectrophotometric and
mendations issued by the World Trade Organization Technical
the potentiometric readout procedures for the ceric-cerous
Barriers to Trade (TBT) Committee.
system.
1.4 This practice applies only to gamma radiation,
2. Referenced documents
X-radiation/bremsstrahlung, and high energy electrons.
3
2.1 ASTM Standards:
1.5 This practice applies provided the following conditions
C912Practice for Designing a Process for Cleaning Techni-
are satisfied:
cal Glasses
2 4
1.5.1 Theabsorbed-doserangeisfrom5×10 to5×10 Gy
E170Terminology Relating to Radiation Measurements and
2
(1).
Dosimetry
6 −1
1.5.2 The absorbed-dose rate does not exceed 10 Gy s
E178Practice for Dealing With Outlying Observations
(1).
E275PracticeforDescribingandMeasuringPerformanceof
1.5.3 For radionuclide gamma-ray sources, the initial pho-
Ultraviolet and Visible Spectrophotometers
ton energy is greater than 0.6 MeV. For bremsstrahlung
E666Practice for CalculatingAbsorbed Dose From Gamma
photons, the initial energy of the electrons used to produce the
or X Radiation
bremsstrahlung photons is equal to or greater than 2 MeV. For
E668 Practice for Application of Thermoluminescence-
electron beams, the initial electron energy is greater than 8
Dosimetry (TLD) Systems for Determining Absorbed
MeV.
DoseinRadiation-HardnessTestingofElectronicDevices
E925Practice for Monitoring the Calibration of Ultraviolet-
1 Visible Spectrophotometers whose Spectral Bandwidth
This practice is under the jurisdiction of ASTM Committee E61 on Radiation
Processing and is the direct responsibility of Subcommittee E61.02 on Dosimetry does not Exceed 2 nm
Systems, and is also under the jurisdiction of ISO/TC 85/WG 3.
E958Practice for Estimation of the Spectral Bandwidth of
Current edition approved March 8, 2017. Published May 2017. Originally
published as ASTM E1205–88. Last previous ASTM edition E1205–99. ASTM
E1205–93 was adopted by ISO in 1998 with the intermediate designation ISO
3
15555:1998(E). The present International Standard ISO/ASTM 51205:2017(E) is a For referenced ASTM and ISO/ASTM standards, visit the ASTM website,
major revision of ISO/ASTM 51205-2009(E). www.astm.org, or contact ASTM Customer Service at [e-mail]. For
2
Theboldfacenumbersinparenthesesrefertothebibliographyattheendofthis Annual Book of ASTM Standards volume information, refer to the standard’s
standard. Document Summary page on the ASTM website.
© ISO/ASTM International 2017 – All rights reserved
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ISO/ASTM 51205:2017(E)
Ultraviolet-Visible Spectrophotometers 3.1.2 ceric-cerous dosimeter—specially prepared solution
3
of ceric sulfate and cerous sulfate in sulfuric acid, individually
2.2 ISO/ASTM Standards:
sealed in an appropriate container such as a glass ampoule,
51261Practice for Calibration of Routine Dosimetry Sys-
tems for Radiation Processing where the radiation-induced changes in electropotential or
optical absorbance of the solution are related to absorbed dose
51707Guide for Estimation of Measurement Uncertainty in
Dosimetry for Radiation Processing to water.
52628Practice for Dosimetry in Radiation Processing
3.1.3 molar linear absorption coeffıcient, ε —constant re-
m
52701Guide for Performance Characterization of Dosim-
lating the spectrophotometric absorbance, A , of an optically
λ
eters and Dosimetry Systems for Use in Radiation Pro-
absorbing molecular species at a given wavelength, λ, per unit
cessing
pathlength, d, to the molar concentration, c, of that species in
4
2.3 ISO Standards:
solution:
12749-4Nuclear energy – Vocabulary – Part 4: Dosimetry
A
λ
for radiation processing ε 5 (1)
m
d·c
4
2.4 ISO/IEC Standards:
2 −1
SI unit: m mol
17025General Requirements for the Competence ofTesting
3.1.3.1 Discussion—The measurement is sometimes ex-
and Calibration Laboratories
−1 −1
pressed in units of L mol cm .
2.5 Joint Committee for Guides in Metrology (JCGM)
Reports:
3.1.4 radiation chemical yield, G(x)—quotient of n(x) by ε¯,
JCGM 100:2008, GUM 1995, with minor correc-
where n(x) is the mean amount of a specified entity, x,
tions,Evaluation of measurement data – Guide to the produced, destroyed, or changed by the mean energy, ε,
¯
5
Expression of Uncertainty in Measurement
imparted to the matter.
JCGM 200:2012 (JCGM 200:2008 with minor revisions),
n x
~ !
VIM,International Vocabulary of Metrology – Basis and G x 5 (2)
~ !
ε¯
6
General Concepts and Associated Terms
−1
SI unit: mol J
2.6 International Commission on Radiation Units and Mea-
7
surements (ICRU) Reports: 3.1.5 reference standard dosimetry system—dosimetry
ICRU Report 10b (NBS Handbook 85)Physical Aspects of
system, generally having the highest metrological quality
Irradiation
available at a given location or in a given organization, from
ICRUReport35 RadiationDosimetry:ElectronBeamswith which measurements made there are derived.
Initial Energies Between 1 and 50 MeV
3.1.6 type 1 dosimeter—dosimeter of high metrological
ICRU Report 80 Dosimetry Systems for Use in Radiation
quality, the response of which is affected by individual influ-
Processing
ence quantities in a well-defined way that can be expressed in
ICRU Report 85a Fundamental Quantities and Units for
terms of independent correction factors.
Ionizing Radiation
3.2 Definitions of Terms Specific to This Standard:
3.2.1 electropotential, E—difference in potential between
3. Terminology
the solutions in the two compartments of an electrochemical
3.1 Definitions:
cell, measured in millivolts.
3.1.1 approved laboratory—laboratory that is a recognized
3.3 Definitions of other terms used in this practice that
nationalmetrologyinstitute,orhasbeenformallyaccreditedto
pertain to radiation measurement and dosimetry may be found
ISO/IEC 17025, or has a quality system consistent with the
in ISO 12749-4, ASTM Terminology E170, ICRU 85a, and
requirements of ISO/IEC 17025.
VIM; these documents, therefore, may be used as alternative
3.1.1.1 Discussion—A recognized national metrology insti-
references.
tute or other calibration laboratory accredited to ISO/IEC
17025 should be used in order to ensure traceability to a
4. Significance and use
national or international standard. A calibration certificate
4.1 The ceric-cerous system provides a reliable means for
provided by a laboratory not having formal recognition or
determining absorbed dose to water. It is based on a process of
accreditation will not necessarily be proof of traceability to a
reductionofcericionstocerousionsinacidicaqueoussolution
national or international standard.
by ionizing radiation (1, 4, ICRU Report 80).
NOTE 3—The ceric-cerous system described in the practice has cerous
4
Available from International Organization for Standardization (ISO), ISO sulfate added to the initial solution to reduce the effect of organic
Central Secretariat, BIBC II, Chemin de Blandonnet 8, CP 401, 1214 Vernier, impurities and to allow the potentiometric method of measurement. Other
Geneva, Switzerland, http://www.iso.org.
systems used for dosimetry include solutions of ceric sulfate or ceric
5
DocumentproducedbyWorkingGroup1oftheJointCommitteeforGuidesin ammonium sulfate in sulfuric acid without the initial addition of cerous
Metrology (JCGM WG1), Available free of charge at the BIPM website (http://
sulfate.Theseothersystemsarebasedonthesameprocessofreductionof
www.bipm.org).
ceric ions to cerous ions but are not included in this practice.
6
DocumentproducedbyWorkingGroup2oftheJointCommitteeforGuidesin
Metrology (JCGM WG2), Available free of charge at the BIPM website (http:// 5. Effect of influence quantities
www.bipm.org).
7 5.1 Guidance on the determination of the performance
Available from International Commission on Radiation Units and
Measurements, 7910 Woodmont Ave., Suite 800, Bethesda, MD 20814, USA. characteristics of dosimeters and dosimetry systems can be
© ISO/ASTM International 2017 – All rights reserved
2

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ISO/ASTM 51205:2017(E)
foundinASTMGuide52701.Therelevantquantitiesthatneed measuring dc potentials in the range from 1 to 100 mV within
tobeconsideredwhenusingtheceric-cerousdosimetrysystem an uncertainty of 1%.
are given below.
NOTE 4—As shown in Fig. A1.1, the electrochemical cell has two
compartments separated by a porous junction, such as a glass frit, a
5.2 The dosimeter response has a temperature dependence
ceramicorkaolinjunction,orafibreglasswick.Theinnercompartmentis
during irradiation that is approximately equal to −0.2% per
always filled with unirradiated solution. The lower compartment is filled
degree Celsius between 0 and 62°C (3, 5, 6). This irradiation
with solution whose response is to be measured (transferred from an
temperature dependence has a slight dependence on the initial
irradiated or unirradiated ampoule). The electropotential, E, generated
cerous ion concentration (see 10.6.2).
between the platinum electrodes in the two compartments is measured by
a digital voltmeter.
5.3 The electropotential, E, within the electrochemical cell,
7.3 Glassware—Borosilicate glass or equivalent chemically
hasapositivetemperaturecoefficientof0.33%per°Cbetween
resistant glass should be used to store the reagents and the
25°C and 30°C and corrections are required for differences
prepared dosimetric solution. All glassware, except ampoules,
betweenmeasurementtemperaturesandthereferencetempera-
should be cleaned using chromic acid cleaning solution or an
ture used during calibration (see 10.5.8)
equivalent cleaning agent (see ASTM Practice C912). Glass-
5.4 No effect of ambient light (even direct sunlight) has
ware should be rinsed at least three times with purified water,
been observed on dosimetric solutions in glass ampoules.
dried thoroughly and stored under conditions that will mini-
5.5 The dosimeter response is dependent on the type and
mize exposure to dust.
energy of the radiation employed. Since cerium is a heavy
7.4 Glass Ampoules—If required, glass ampoules should be
element from the viewpoint of absorption characteristics of
cleaned in boiling purified water, rinsed twice with purified
gamma radiation, the response of the dosimetric solution for
water, and oven dried.
lowerenergydegradedradiationduringusemybegreaterthan
NOTE 5—The dosimetric ampoule normally used has a capacity of
the response in the cobalt-60 radiation during calibration (7).
approximately 2 mL. Quick-break glass ampoules, or Type 1 glass
However, studies in an industrial gamma irradiator indicate
colorbreak ampoules or equivalent containers, are commonly used.
that this effect is small (8).
Commercially available ampoules have been found to give reproducible
results without requiring additional cleaning.
5.6 Ifthedosimetricsolutionispreparedasdescribedinthis
document, and steps are taken to avoid contamination, the
8. Reagents
dosimetric solution stored, or sealed, in glass vessels (for
8.1 Analytical reagent grade (or better) chemicals shall be
example, ampoules) is stable for several years before and after
8
used for preparing all solutions.
irradiation.
8.2 Water quality is very important since it is the major
6. Interferences
component of the dosimetric solutions, and therefore may be
6.1 The ceric-cerous dosimetric response is sensitive to theprimesourceofcontamination.Double-distilledwaterfrom
coupled all-glass and silica stills or water from a high-quality
impurities, particularly organic impurities. Even in trace
quantities, impurities can cause a detectable change in the commercial purification unit capable of achieving Total Oxi-
dizable Carbon (T.O.C.) content below 5 ppb should be used.
observed response (9). Organic materials should not be used
for any component in contact with the solution unless they Use of deionized water is not recommended.
have been tested and shown to have no effect. The effect of
NOTE 6—Double-distilled water distilled from an alkaline potassium
trace impurities is minimized by the addition of cerous ions to
permanganate (KMnO ) solution (2 g KMnO plus 5 g sodium hydroxide
4 4
the solution (10, 11). Water purification methods found to be (NaOH)pelletsin2Lofdistilledwater)hasbeenfoundtobeadequatefor
routine preparation of the dosimetric solution. High-purity water is
adequate for use in preparing ceric-cerous dosimeters are
commercially available from some suppliers. Such water labeled HPLC
decribed in 8.2.
(high-pressure liquid chromatographic) grade is usually sufficiently free
6.2 Undesirablechemicalchangesinthedosimetricsolution from organics to be used in this practice.
can occur if care is not taken during sealing of the ampoules
8.3 Purified water used in this practice should not be stored
(see 9.7).
in plastic containers or in containers with plastic cap liners.
7. Apparatus
9. Preparation of the dosimeters
7.1 Spectrophotometric Method—For the analysis of the
9.1 Recommended concentrations for the ceric-cerous do-
dosimetric solution, a high-precision spectrophotometer ca-
simeter for measurement of absorbed doses from about 5 to 50
−3
pable of measuring absorbance values up to two with an
kGy (high-range dosimeter) are 15 mmol dm ceric sulfate
−3
uncertainty of no more than 1% in the analysis wavelength
[Ce(SO ) ·4H O] and 15 mmol dm cerous sulfate
4 2 2
region from 254 to 320 nm should be used. Quartz cuvettes
[Ce (SO ) ·8H O]. For measurement of absorbed doses from
2 4 3 2
with10-mmpathlengthshouldbeusedforspectrophotometric
about 0.5 to 10 kGy (low-range dosimeter), the recommended
−3
measurements of absorbance of the solution.
concentrations are 3 mmol dm [Ce(SO ) ·4H O] and 3
4 2 2
−3
mmol dm [Ce (SO ) ·8H O].
7.2 Potentiometric Method—An electrochemical cell, simi- 2 4 3 2
lar to that described in Annex A1, should be used (see Fig.
A1.1). The electropotential across the cell should be measured 8
Reagent specifications are available from American Chemical Society, 1115
th
with a high-precision digital voltmeter that is capable of 16 St., Northwest, Washington, DC 20036, USA.
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ISO/ASTM 51205:2017(E)
9.2 The dosimetric solutions specified in9.1 may be formu- concentration, cerous-ion concentration, ceric-ion molar linear
lated from the following nominal stock solutions: (a) 0.4 mol absorption coefficient, radiation chemical yield for the cerous
−3 −3 −3
dm and 4 mol dm sulfuric acid (H SO ), (b) 0.1 mol dm ion, and density with acceptable values. Procedures for per-
2 4
−3
Ce(SO ) ·4H O, and (c) 0.1 mol dm Ce (SO ) ·8H O. forming these measurements are given in Annex A3. Quality
4 2 2 2 4 3 2
Procedures for preparing these solutions are given in Annex control testing following ampouling is performed by compar-
A2.(Warning—Concentrated sulfuric acid is corrosive and ing calibration data for the new dosimeter batch with data
can cause serious burns. Ceric-cerous solutions are skin irri- obtained from previous batches (see 10.6.4).
tants.Appropriate precautions should be exercised in handling
9.7 Prepare dosimeters by filling ampoules with approxi-
these materials.)
mately 2 mLof dosimetric solution. Take care not to contami-
9.3 Use the following equations to determine the volume in nate the dosimetric solution with impurities. Exercise care in
millilitres of each stock solution necessary to prepare 1 L of filling ampoules to avoid depositing solution in the ampoule
dosimetric solution: neck. Subsequent heating during sealing may cause an unde-
High Range Low Range sirable chemical change in the dosimetric solution remaining
inside the ampoule neck. Flame seal the ampoules, exercising
V 0.015 V 0.003
care to avoid heating the body of the ampoule during sealing.
1 1
5 5 (3)
1000 c 1000 c
1 1
9.8 Store dosimeters in a dark place at room temperature
(23 65°C).
V 0.015 V 0.003
2 2
5 5 (4)
1000 c 1000 c 10. Calibration of the dosimetry system
2 2
10.1 Prior to use, the dosimetry system (consisting of a
specific batch of dosimeters and specific measurement instru-
V 0.4 V 0.4
3 3
5 5 (5)
ments) shall be calibrated in accordance with the user’s
10002 V c 10002 V c
1 3 1 3
documented procedure that specifies details of the calibration
and quality assurance requirements. This calibration shall be
V 5 10002 V 2 V 2 V V 5 10002 V 2 V 2 V (6)
4 1 2 3 4 1 2 3 repeated at regular intervals to ensure that the accuracy of the
absorbed-dose measurement is maintained within required
limits. Calibration for routine dosimetry systems are described
where:
−3
in ISO/ASTM Practice 51261.
V = volume of nominal 0.1 mol dm ceric-sulfate stock
1
solution,
10.2 Calibration Irradiation of Dosimeters—Irradiation is a
−3
V = volume of nominal 0.1 mol dm cerous-sulfate stock
2 critical component of the calibration of the dosimetry system.
solution,
10.2.1 When the ceric-cerous dosimeter is used in a refer-
−3
V = volume of nominal 4 mol dm sulfuric-acid stock
3
ence standard dosimetry system, calibration irradiations shall
solution,
be performed at an approved laboratory, as defined in 3.1.1.
V = volume of purified water,
4
10.2.2 When the ceric-cerous dosimeter is used in a routine
c = actual concentration of the ceric-sulfate stock solution,
1
dosimetrysystem,thecalibrationirradiationmaybeperformed
c = actual concentration of the cerous-sulfate stock
2
in accordance with 10.2.1, or at a production or research
solution, and
−3 irradiationfacilitytogetherwithreference-ortransfer-standard
c = actual concentration of the nominal 4 mol dm
3
dosimetersfromalaboratorythathasmeasurementtraceability
sulfuric-acid stock solution.
−3 to nationally or internationally recognized standards.
NOTE 7—If the nominal concentrations of c = c = 0.1 mol dm , and
1 2
−3
10.2.3 Specify the calibration dose in terms of absorbed
c = 4 mol dm are assumed, then V = V = 150 mL for the high range
3 1 2
andV =V =30mLforthelowrange;V =85mLforthehighrangeand dose to water.
1 2 3
V = 97 mL for the low range. If the concentrations of the various stock
3 10.2.4 Forcalibrationwithphotons,theceric-cerousdosim-
solutions are significantly different from the nominal values, then use Eq
eter shall be irradiated under conditions that approximate
4-6todeterminetheexactvolumes.Toprepareavolumeofthedosimetric
electron equilibrium.
solution other than 1000 mL, the result of these equations should be
10.2.5 The dosimeter shall be calibrated in a radiation field
multiplied by the ratio of the desired volume in millilitres to 1000 mL.
of the same type and energy as that in which it is to be used,
9.4 Determine all of the volumes given in 9.3 using a
unless evidence is available to demonstrate equivalence of
calibratedvolumetricflaskthatcanbereadtowithin 60.5mL.
response. If not, a correction factor has to be applied and its
9.5 Transfer the volume of each component of the dosim-
associateduncertaintymustbeaddedtotheuncertaintybudget.
etricsolutionintoa1-Lorlargerglassstoragecontainer.Rinse
10.2.6 Control (or monitor) the temperature of the dosim-
thevolumetricflaskusedformeasuringV ,V ,andV byusing
1 2 3
eters during irradiation. Calculate or measure the mean irra-
some portion of the purified water of V . Stopper the container
4
diationtemperatureofeachdosimetertoanaccuracyof 62°C,
and shake well. Before use, allow the dosimetric solution to
or better.
stand for at least five days in the dark (ICRU 10b).
10.2.7 Use a set of at least three dosimeters for each
9.6 Qualitycontroltestingofthedosimetricsolutionpriorto absorbed dose value.
ampouling is performed by comparing the measurement of 10.2.8 Irradiate these sets of dosimeters to at least five
dosimetric solution parameters, such as ceric-ion known dose values for each factor of ten span of absorbed
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ISO/ASTM 51205:2017(E)
dosescoveringtherangeofutilizationinordertodeterminethe 10.4.5 Calculations:
calibration curve for the dosimetry system. 10.4.5.1 Calculate the mean absorbance of the unirradiated
¯
dosimeters, A .
0
10.3 Measurement Instrument Calibration and Perfor-
10.4.5.2 Calculate the net absorbance, ∆A, for each irradi-
mance Verification—For the calibration of instruments (spec-
ated dosimeter:
trophotometer or digital voltmeter), and for the verification of
¯
instrument performance between calibrations, see ISO/ASTM
∆A 5 A 2 A (7)
0
Practice 51261 and/or instrument-specific manuals.
10.5 Potentiometric Measurement:
10.3.1 Spectrophotometer Performance:
10.5.1 Place contents of an unirradiated dosimeter (am-
10.3.1.1 Check the wavelength scale of the spectrophotom-
poule) into both compartments of the electrochemical cell. See
eter and establish its accuracy. The emission spectrum from a 9
Annex A1 for a description of the electrochemical cell.
low-pressure mercury arc lamp can be used for this purpose.
10.5.2 Allow the solution to remain in the electrochemical
Such a lamp may be obtained from the spectrophotomete
...