ISO/ASTM 51538:2017

Practice for use of the ethanol-chlorobenzene dosimetry system

1.1 This practice covers the preparation, handling, testing, and procedure for using the ethanol-chlorobenzene (ECB) 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 ECB system. The ECB dosimeter is classified as a type I dosimeter on the basis of the effect of influence quantities. The ECB dosimetry system may be used as a reference standard dosimetry system or as a routine dosimetry system. 1.2 ISO/ASTM 51538 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 ECB system. It is intended to be read in conjunction with ISO/ASTM Practice 52628. 1.3 This practice describes the mercurimetric titration analysis as a standard readout procedure for the ECB dosimeter when used as a reference standard dosimetry system. Other readout methods (spectrophotometric, oscillometric) that are applicable when the ECB system is used as a routine dosimetry system are described in Annex A1 and Annex A2. 1.4 This practice applies only to gamma radiation, X-radiation/bremsstrahlung, and high energy electrons. 1.5 This practice applies provided the following conditions are satisfied: 1.5.1 The absorbed dose range is between 10 Gy and 2 MGy for gamma radiation and between 10 Gy and 200 kGy for high current electron accelerators (1, 2) (Warning?the boiling point of ethanol chlorobenzene solutions is approximately 80 °C. Ampoules may explode if the temperature during irradiation exceeds the boiling point. This boiling point may be exceeded if an absorbed dose greater than 200 kGy is given in a short period of time.) 1.5.2 The absorbed-dose rate is less than 106 Gy s−1(2). 1.5.3 For radionuclide gamma-ray sources, the initial pho-ton energy is greater than 0.6 MeV. For bremsstrahlung photons, the energy of the electrons used to produce the bremsstrahlung photons is equal to or greater than 2 MeV. For electron beams, the initial electron energy is greater than 8 MeV (3). NOTE 1 The same response relative to 60Co gamma radiation was obtained in high-power bremsstrahlung irradiation produced bya5MeV electron accelerator (4). NOTE 2 The lower energy limits are appropriate for a cylindrical dosimeter ampoule of 12-mm diameter. Corrections for dose gradients across the ampoule may be required for electron beams. The ECB system may be used at lower energies by employing thinner (in the beam direction) dosimeters (see ICRU Report 35). The ECB system may also be used at X-ray energies as low as 120 kVp (5). However, in this range of photon energies the effect caused by the ampoule wall is considerable. NOTE 3 The effects of size and shape of the dosimeter on the response of the dosimeter can adequately be taken into account by performing the appropriate calculations using cavity theory (6). 1.5.4 The irradiation temperature of the dosimeter is within the range from −30 °C to 80 °C. NOTE 4 The temperature dependence of dosimeter response is known only in this range (see 5.2). For use outside this range, the dosimetry system should be calibrated for the required range of irradiation tempera-tures. 1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. Specific warnings are given in 1.5.1, 9.2 and 10.2. 1.7 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for the Development of International Standards, Guides and Recom-mendations issued by the World Trade Organization Technical

Pratique de l'utilisation d'un système dosimétrique à l'éthanol chlorobenzène

General Information

• Status: Published
• Publication Date: 02-Oct-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: 9060 - Close of review
• Start Date: 03-Jun-2028

Relations

• Revises: ISO/ASTM 51538:2009 - Practice for use of the ethanol-chlorobenzene dosimetry system
• Effective Date: 10-Dec-2016

Standards Content (Sample)

INTERNATIONAL ISO/ASTM
STANDARD 51538
Third edition
2017-09
Practice for use of the ethanol-
chlorobenzene dosimetry system
Pratique de l'utilisation d'un système dosimétrique à l'éthanol
chlorobenzène
Reference number
ISO/ASTM 51538:2017(E)
©
ISO/ASTM International 2017

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ISO/ASTM 51538:2017(E)

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ii © ISO/ASTM International 2017 – All rights reserved

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ISO/ASTM 51538:2017(E)
Contents Page
1 Scope. 1
2 Referenced documents. 2
3 Terminology. 2
4 Significance and use. 3
5 Effect of Influence Quantities. 3
6 Interferences. 4
7 Apparatus. 4
8 Reagents. 4
9 Preparation of dosimeters. 4
10 Calibration of the mercuric nitrate solution. 5
11 Calibration of the dosimetry system. 5
12 Application of dosimetry system. 6
13 Minimum documentation requirements. 6
14 Measurement Uncertainty. 6
15 Keywords. 6
Annexes. 7
Table 1 Radiationchemicalyields(G)fortheformationofHClintypicalECBsolutionformulations. 3
−1
Table 2 Temperature coefficients k (°C) for typical ECB solution formulations as derived from
Ref (17). 4
Table A3.1 Characteristics of some applicable methods. 10
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ISO/ASTM 51538:2017(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
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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 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).
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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 51538:2009), 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 51538:2017(E)
Standard Practice for
1
Use of the Ethanol-Chlorobenzene Dosimetry System
This standard is issued under the fixed designation ISO/ASTM 51538; 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 point of ethanol chlorobenzene solutions is approximately
80 °C. Ampoules may explode if the temperature during
1.1 This practice covers the preparation, handling, testing,
irradiation exceeds the boiling point. This boiling point may be
and procedure for using the ethanol-chlorobenzene (ECB)
exceeded if an absorbed dose greater than 200 kGy is given in
dosimetry system to measure absorbed dose to water when
a short period of time.)
exposed to ionizing radiation. The system consists of a
6 −1
1.5.2 The absorbed-dose rate is less than 10 Gy s (2).
dosimeter and appropriate analytical instrumentation. For
1.5.3 For radionuclide gamma-ray sources, the initial pho-
simplicity, the system will be referred to as the ECB system.
ton energy is greater than 0.6 MeV. For bremsstrahlung
The ECB dosimeter is classified as a type I dosimeter on the
photons, the energy of the electrons used to produce the
basis of the effect of influence quantities. The ECB dosimetry
bremsstrahlung photons is equal to or greater than 2 MeV. For
system may be used as a reference standard dosimetry system
electron beams, the initial electron energy is greater than 8
or as a routine dosimetry system.
MeV (3).
1.2 This document is one of a set of standards that provides
60
NOTE 1—The same response relative to Co gamma radiation was
recommendations for properly implementing dosimetry in
obtained in high-power bremsstrahlung irradiation produced bya5MeV
radiation processing, and describes a means of achieving
electron accelerator (4).
compliance with the requirements of ISO/ASTM Practice
NOTE 2—The lower energy limits are appropriate for a cylindrical
52628 for the ECB system. It is intended to be read in dosimeter ampoule of 12-mm diameter. Corrections for dose gradients
across the ampoule may be required for electron beams. The ECB system
conjunction with ISO/ASTM Practice 52628.
may be used at lower energies by employing thinner (in the beam
1.3 This practice describes the mercurimetric titration
direction) dosimeters (see ICRU Report 35). The ECB system may also be
used at X-ray energies as low as 120 kVp (5). However, in this range of
analysis as a standard readout procedure for the ECB dosimeter
photon energies the effect caused by the ampoule wall is considerable.
when used as a reference standard dosimetry system. Other
NOTE 3—The effects of size and shape of the dosimeter on the response
readout methods (spectrophotometric, oscillometric) that are
of the dosimeter can adequately be taken into account by performing the
applicable when the ECB system is used as a routine dosimetry
appropriate calculations using cavity theory (6).
system are described in Annex A1 and Annex A2.
1.5.4 The irradiation temperature of the dosimeter is within
1.4 This practice applies only to gamma radiation,
the range from −30 °C to 80 °C.
X-radiation/bremsstrahlung, and high energy electrons.
NOTE 4—The temperature dependence of dosimeter response is known
only in this range (see 5.2). For use outside this range, the dosimetry
1.5 This practice applies provided the following conditions
system should be calibrated for the required range of irradiation tempera-
are satisfied:
tures.
1.5.1 The absorbed dose range is between 10 Gy and 2 MGy
1.6 This standard does not purport to address all of the
for gamma radiation and between 10 Gy and 200 kGy for high
2 safety concerns, if any, associated with its use. It is the
current electron accelerators (1, 2). (Warning—the boiling
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
1
This practice is under the jurisdiction of ASTM Committee E61 on Radiation
bility of regulatory limitations prior to use. Specific warnings
Processing and is the direct responsibility of Subcommittee E61.02 on Dosimetry
are given in 1.5.1, 9.2 and 10.2.
Systems, and is also under the jurisdiction of ISO/TC 85/WG 3.
1.7 This international standard was developed in accor-
Current edition approved April 25, 2017. Published June 2017. Originally
dance with internationally recognized principles on standard-
published as ASTM E1538-93. Last previous ASTM edition E1538–99. ASTM
E1538–93 was adopted by ISO in 1998 with the intermediate designation ISO
ization established in the Decision on Principles for the
15563:1998(E). The present International Standard ISO/ASTM 51538:2017 (E) is a
Development of International Standards, Guides and Recom-
major revision of ISO/ASTM 51538:2009(E). DOI:10.1520/ISOASTM51538-17.
2
mendations issued by the World Trade Organization Technical
The boldface numbers in parentheses refer to the bibliography at the end of this
practice. Barriers to Trade (TBT) Committee.
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ISO/ASTM 51538:2017(E)
2. Referenced documents 2.6 International Commission on Radiation Units and Mea-
7
surements (ICRU) Reports:
3
2.1 ASTM Standards:
ICRU Report 35 Radiation Dosimetry: Electrons with Initial
C912 Practice for Designing a Process for Cleaning Techni-
Energies Between 1 and 50 MeV
cal Glasses
ICRU Report 80 Dosimetry Systems for Use in Radiation
D1193 Specification for Reagent Water
Processing
E170 Terminology Relating to Radiation Measurements and
ICRU Report 85a Fundamental Quantities and Units for
Dosimetry
Ionizing Radiation
E275 Practice for Describing and Measuring Performance of
Ultraviolet and Visible Spectrophotometers
3. Terminology
E666 Practice for Calculating Absorbed Dose From Gamma
3.1 Definitions:
or X Radiation
3.1.1 approved laboratory—laboratory that is a recognized
E668 Practice for Application of Thermoluminescence-
national metrology institute, or has been formally accredited to
Dosimetry (TLD) Systems for Determining Absorbed
ISO/IEC 17025, or has a quality system consistent with the
Dose in Radiation-Hardness Testing of Electronic Devices
requirements of ISO/IEC 17025.
E925 Practice for Monitoring the Calibration of Ultraviolet-
3.1.1.1 Discussion—A recognized national metrology insti-
Visible Spectrophotometers whose Spectral Bandwidth tute or other calibration laboratory accredited to ISO/IEC
17025 should be used in order to ensure traceability to a
does not Exceed 2 nm
national or international standard. A calibration certificate
E958 Practice for Estimation of the Spectral Bandwidth of
provided by a laboratory not having formal recognition or
Ultraviolet-Visible Spectrophotometers
accreditation will not necessarily be proof of traceability to a
3
2.2 ISO/ASTM Standards:
national or international standard.
51261 Practice for Calibration of Routine Dosimetry Sys-
3.1.2 calibration—set of operations that establish, under
tems for Radiation Processing
specified conditions, the relationship between values indicated
51707 Guide for Estimation of Measurement Uncertainty in
by a measuring instrument or measuring system, or values
Dosimetry for Radiation Processing
represented by a material measure or a reference material, and
52628 Practice for Dosimetry in Radiation Processing
the corresponding values realised by standards.
52701 Guide for Performance Characterization of Dosim-
3.1.2.1 Discussion—Calibration conditions include environ-
eters and Dosimetry Systems for Use in Radiation Pro-
mental and irradiation conditions present during irradiation,
cessing
storage and measurement of the dosimeters that are used for the
4
2.3 ISO Standards: generation of a calibration curve.
12749-4 Nuclear energy – Vocabulary – Part 4: Dosimetry
3.1.3 calibration curve—expression of the relation between
for radiation processing
indication and corresponding measured quantity value.
4
3.1.3.1 Discussion—In radiation processing standards, the
2.4 ISO/IEC Standards:
term “dosimeter response” is generally used for “indication”.
17025 General Requirements for the Competence of Testing
3.1.4 dosimetry system—system used for determining ab-
and Calibration Laboratories
sorbed dose, consisting of dosimeters, measurement instru-
2.5 Joint Committee for Guides in Metrology (JCGM)
ments and their associated reference standards, and procedures
Reports:
for the system’s use.
JCGM 100:2008, GUM 1995, with minor correctons Evalu-
3.1.5 ethanol-chlorobenzene dosimeter—partly deoxygen-
ation of measurement data – Guide to the Expression of
ated solution of chlorobenzene (CB) in 96 volume % ethanol in
5
Uncertainty in Measurement
an appropriate container, such as a flame-sealed glass ampoule,
JCGM 200:2012, (JCGM 200:2008 with minor revi-
used to indicate absorbed dose by measurement of the amount
sions) VIM, International Vocabulary of Metrology –
of HCl formed under irradiation.
6
Basis and General Concepts and Associated Terms
3.1.6 measurement management system—set of interrelated
or interacting elements necessary to achieve metrological
confirmation and continual control of measurement processes.
3
For referenced ASTM and ISO/ASTM standards, visit the ASTM website,
3.1.7 metrological traceability—property of a measurement
www.astm.org, or contact ASTM Customer Service at [e-mail]. For
whereby the result can be related to a reference through a
Annual Book of ASTM Standards volume information, refer to the standard’s
Document Summary page on the ASTM website.
documented unbroken chain of comparisons, each contributing
4
Available from International Organization for Standardization (ISO), ISO
to the measurement uncertainty.
Central Secretariat, Chemin de Blandonnet 8, CP 401, 1214 Vernier, Geneva,
Switzerland, http://www.iso.org. 3.1.8 molar linear absorption coeffıcient ε —constant relat-
m
5
Document produced by Working Group I of the Joint Committee for Guides in
ing the spectrophotometric absorbance, A , of an optically
λ
Metrology (JCGM WG1). Available free of charge at the BIPM website (http://
www.bipm.org).
6
Document produced by Working Group 2 of the Joint Committee for Guides in
7
Metrology (JCGM WG2). Available free of charge at the BIPM website (http:// Available from the Commission on Radiation Units and Measurements, 7910
www.bipm.org). Woodmont Ave., Suite 800, Bethesda, MD 20814, USA.
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ISO/ASTM 51538:2017(E)
TABLE 1 Radiation chemical yields (G) for the formation of HCl
absorbing molecular species at a given wavelength, λ, per unit
in typical ECB solution formulations
pathlength, d, to the molar concentration, c, of that species in
Radiation Chemical Yields
solution:
B −1
at 20 °C (µmol · J )
A 60
Concentration Density at 20 °C Ratio of
λ
Co 4to10MeV
ϵ 5 (1)
−3 A
m of CB, vol % kg · m Coefficients
d 3c Gamma Electrons (3)
Radiation
2 −1
(SI unit: m mol ) (9)
C
3.1.8.1 Discussion—It is sometimes expressed in units of L 4 819 0.989 0.42
−1 −1
10 839 0.995 0.52
mol cm .
20 869 1.006 0.59
D
3.1.9 radiation chemical yield G(x)—quotient of n(x) by ε 24 880 1.011 0.60 0.57
¯
40 925 1.027 0.63
where n(x) is the mean amount of a specified entity, x,
A
The ratio of the photon mass energy-absorption coefficients for water and the
produced, destroyed, or changed by the mean energy, ε
¯
m
60
dosimeter solution at Co gamma ray energy:
imparted to the matter.
µ /ρ
s d
en
w
f5
G x 5 n x /ε¯ (2)
~ ! ~ !
µ /ρ
s d
en
D
−1
B
(SI unit: mol J )
Radiation chemical yield of HCl in the dose range from 100 Gy to 100 kGy.
C
Upper dose range 20 kGy.
3.1.10 reference standard dosimetry system—dosimetry
D
Lower dose range 1 kGy. This formulation also contained 0.04 % acetone and
system, generally having the highest metrological quality 0.04 % benzene.
available at a given location, from which measurements made
there are derived.
3.1.11 routine dosimetry system—dosimetry system cali-
4.4 The concentration of chlorobenzene in the solution can
brated against a reference standard dosimetry system and used
be varied so as to simulate a number of materials in terms of
for routine absorbed-dose measurements, including dose map-
the photon mass energy-absorption coefficients (µ /ρ) for X-
en
ping and process monitoring.
and gamma radiation, and electron mass collision stopping
−2
3.1.12 type 1 dosimeter—dosimeter of high metrological
powers (S/ρ), over a broad energy range from 10 to 100 MeV
quality, the response of which is affected by individual influ-
(11-14).
ence quantities in a well-defined way that can be expressed in
4.5 The ECB dosimetry system may be used with other
terms of independent correction factors.
radiation types, such as neutrons (15), and protons (16).
3.2 Definitions of Terms Specific to This Standard:
Meaningful dosimetry of any radiation types and energies
3.2.1 conductometry—analytical method based on the mea-
novel to the system’s use requires that the respective radiation
surement of conductivity of solutions.
chemical responses applicable under the circumstances be
3.2.1.1 Discussion—The conductivity of a solution depends
established in advance.
on the concentration of free ions in the solution.
5. Effect of Influence Quantities
3.2.2 oscillometry—electroanalytical method of conductiv-
ity measurements, when high-frequency (1 to 600 MHz)
5.1 Guidance on the determination of the performance
alternating current is applied to measure or follow changes in
characteristics of dosimeters and dosimetry systems can be
the composition of chemical systems.
found in ISO/ASTM Guide 52701. The relevant influence
quantities that need to be considered when using the ECB
3.3 Definitions of other terms used in this standard that
dosimetry system are given below.
pertain to radiation measurement and dosimetry may be found
in ISO 12749-4, ASTM Terminology E170, ICRU 85a and
5.2 The irradiation temperature dependence of dosimeter
VIM; these definitions, therefore, may be used as an alternative
response is a complex function of dose and temperature for
references.
each concentration of chlorobenzene (that is, for each formu-
lation). This dependence arises directly from the temperature
4. Significance and use
dependence of radiation chemical yield, G. The analysis of the
4.1 The ECB dosimetry system provides a reliable means of
published data (17) shows that the irradiation temperature
measuring absorbed dose to water. It is based on a process of
dependence of G between 20 °C and 80 °C at any chloroben-
radiolytic formation of hydrochloric acid (HCl) in aqueous
zene concentration can be described by a simple exponential
ethanolic solutions of chlorobenzene by ionizing radiation ((7,
expression:
8), ICRU 80).
G 5 G exp k t 2 20 (3)
@ ~ !#
t 0
4.2 The dosimeters are partly deoxygenated solutions of
where:
chlorobenzene (CB) in 96 volume % ethanol in an appropriate
−1
G = radiation chemical yield in µmol J at a given tem-
container, such as a flame-sealed glass ampoule. Radiation
t
chemical yields (G) for the formation of HCl in typical ECB perature t in °C,
−1
G = radiation chemical yield in µmol J at 20 °C (G for
solution formulations are given in Table 1.
0 0
different ECB solutions are given in Table 1), and
4.3 The irradiated solutions indicate absorbed dose by the
−1
k = temperature coefficient in °C applicable at a given
amount of HCl formed. A number of analytical methods are
dose.
available for measuring the amount of HCl in ethanol (10).
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ISO/ASTM 51538:2017(E)
5.2.1 The values of k are given in Table 2. ness of such material depends on the energy of the photon (see
ASTM Practices E666 and E668).
6. Interferences
NOTE 5—The dosimetric ampoule commonly used has a capacity of
6.1 The ECB dosimetric solution response is not particu-
about 5 mL. Quick-break, glass ampoules or “Type 1 glass” colorbreak
ampoules or equivalent containers, may be used. Commercially available
larly sensitive to impurities which occur in commercially
pharmaceutical ampoules have been found to give reproducible results
available components, chlorobenzene and ethanol of the ana-
without requiring additional cleaning.
lytical reagent (AR) grade purity or equivalent (pro analysi,
p.a., and puriss). For high-accuracy results, organic materials
8. Reagents
of technical grade purity (or purum) can be purified by
8.1 Analytical reagent grade chemicals shall be used in this
distillation.
8
practice for preparing all solutions.
6.2 Care should be exercised in filling ampoules to avoid
8.2 Triply distilled water from coupled all-glass stills or
depositing solution in the ampoule neck. Subsequent heating
water from a high-quality commercial purification unit capable
during sealing of the ampoule may cause an undesirable
of achieving Total Oxidizable Carbon (T.O.C.) content below 5
chemical change in the dosimetric solution remaining inside
ppb should be used. Type II reagent water as specified in
the ampoule neck. Test tubes with ground-glass stoppers are
ASTM Specification D1193 is also considered to be of suffi-
therefore preferred to sealed ampoules for measuring doses
cient quality for use in preparing solutions and 96 volume %
below 100 Gy. For the same reason, care should be given to
ethanol.
avoid heating the body of the ampoule during sealing.
NOTE 6—High-purity water is commercially available from some
6.3 The dosimetric solution is somewhat sensitive to ultra-
suppliers. Such water, labelled HPLC (high-pressure liquid chromatogra-
violet light and should be kept in the dark for long-term
phy) grade, is usually sufficiently free of impurities to be used in this
storage. No special precautions are required during routine
practice.
handling under normal laboratory lighting conditions, but
strong ultraviolet (UV) sources such as sunlight should be
9. Preparation of dosimeters
avoided (18).
9.1 Dosimetric solutions may contain any concentration of
CB. For practical reasons, only a few characteristic formula-
7. Apparatus
tions have been thoroughly characterized. Table 1 lists these
7.1 This practice describes mercurimetric titration of radi-
typical formulations in terms of CB concentrations and radia-
−
olytically formed Cl ions as a standard readout procedure for
tion chemical yields pertaining to these concentrations.
the ECB system when used as a reference-standard dosimetry
9.2 Prepare 96 volume % aqueous ethanol first by adding
system.
absolute ethanol into a volumetric flask containing the appro-
7.2 For the analysis of the dosimetric solution, use a
priate amount of water. (Warning—Ethanol is flammable.)
precision burette capable of measuring volumes with 0.01 mL
Use this aqueous ethanol for making the dosimetric solutions
resolution. If necessary, check the original calibration of
of the desired concentrations by adding it into volumetric flasks
volumetric glassware and, if necessary, recalibrate to attain
containing appropriate amounts of CB. Store the dosimetric
0.1 % relative uncertainty. Control the temperature of all
solution in the dark. (Warning—Chlorobenzene is toxic and a
solutions during handling at 20 6 2 °C to ensure correct
skin irritant. Appropriate precaution should be taken to avoid
measurement of volumes.
contact with the solution during preparation and analysis of the
7.3 Use borosilicate glass or equivalent chemically resistant
dosimeters. Used solutions should be disposed of as hazardous
glass to store the reagents and the prepared dosimetric solution,
waste.)
and to perform the titration. Clean all apparatus thoroughly
9.3 Fill the dosimeter ampoules with the dosimetric solu-
before use (see ASTM Practice C912).
tion. Bubble the solution in the ampoule with nitrogen for
7.4 Use a sealed glass ampoule or other appropriate glass about 1 min at about 1 bubble per second through a 1-mm
container to hold the dosimetric solution during irradiation. For
capillary. Flame-seal immediately after bubbling. Exercise care
photons, surround the container with material of thickness
to avoid depositing solution in the ampoule neck. Store
sufficient to produce approximate electron equilibrium condi-
dosimeters in the dark.
tions during calibration irradiations. For measurement of ab-
sorbed dose in water, use materials that have radiation-
absorption properties essentially equivalent to water, for 8
Reagent specifications are available from the American Chemical Society, 1115
example, polystyrene and polyethylene. The appropriate thick- 16th Street, NW, Washington, DC 20036, USA.
−1
TABLE 2 Temperature coefficients k (°C) for typical ECB solution formulations as derived from Ref (17)
Concentration of CB, vol % 2.5 kGy 5 kGy 10 kGy 15 kGy 20 kGy 25 kGy
4 −0.0002 −0.0004 −0.0007 −0.0011 −0.0015 −0.0019
10 0.0018 0.0014 0.0009 0.0002 0.0 0.0
20, 25, 40 0.0037 0.0031 0.0020 0.0013 0.0008 0.0
NOTE 1— For intermediate doses interpolation should be made.
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ISO/ASTM 51538:2017(E)
NOTE 7—To minimize the removal of the vapor above the dosimetic
11.2 Calibration Irradiation of Dosimeters—Irradiation is a
solution in the ampoules, the nitrogen is saturated with the vapors of the
critical component of the calibration of the dosimetry system.
dosimetric solution by passing it through ECB solution of the same
Calibration irradiations shall be performed at an approved
composition before the bubbling of the dosimeter ampoules.
laboratory.
11.2.1 Specify the dose in terms of absorbed dose to water.
10. Calibration of the mercuric nitrate solution
11.2.2 When the ECB dosimeter is used as a routine
10.1 The dosimeter measurement procedure is based on the
dosimeter, the calibration irradiation may be performed by
titration of chloride ions formed by irradiation. Free chloride is
irradiating the dosimeters at (a) an approved laboratory using
precipitated with mercuric ions as insoluble HgCl , where-
2 criteria specified in ISO/ASTM Practice 51261,(b) an in-house
2+
upon the excess of Hg ions gives a violet-red coloration with
calibration facility that provides an absorbed dose (or an
the indicator diphenylcarbazone in acid medium (19).
absorbed-dose rate) having traceability to nationally or inter-
−4 −3
nationally recognized standards, or (c) a production irradiator
10.2 Prepare approximately5×10 mol dm Hg(NO ) in
3 2
under actual production irradiation conditions, together with
acidic aqueous ethanol. First dissolve an appropriate amount of
reference- or transfer-standard dosimeters issued and read by
Hg(NO ) in water acidified with sufficient HNO to attain the
3 2 3
−3
an approved laboratory
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