ASTM ISO/ASTM51205-17

Standard Practice for Use of a Ceric-Cerous Sulfate Dosimetry System

SIGNIFICANCE AND USE
4.1 The ceric-cerous system provides a reliable means for determining absorbed dose to water. It is based on a process of reduction of ceric ions to cerous ions in acidic aqueous solution by ionizing radiation (1, 4, ICRU Report 80).
Note 3: The ceric-cerous system described in the practice has cerous sulfate added to the initial solution to reduce the effect of organic impurities and to allow the potentiometric method of measurement. Other systems used for dosimetry include solutions of ceric sulfate or ceric ammonium sulfate in sulfuric acid without the initial addition of cerous sulfate. These other systems are based on the same process of reduction of ceric ions to cerous ions but are not included in this practice.
SCOPE
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 This document 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.  
1.5 This practice applies provided the following conditions are satisfied:  
1.5.1 The absorbed-dose range is from 5 × 102 to 5 × 104 Gy (1).2  
1.5.2 The absorbed-dose rate does not exceed 106 Gy s−1 (1).  
1.5.3 For radionuclide gamma-ray sources, the initial photon energy is greater than 0.6 MeV. For bremsstrahlung photons, the initial 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.
Note 1: The lower energy limits are appropriate for a cylindrical dosimeter ampoule of 12-mm diameter. Corrections for dose gradient across the ampoule may be required for electron beams (2). The ceric-cerous system may be used at lower energies by employing thinner (in the beam direction) dosimeters (see ICRU Report 35).  
1.5.4 The irradiation temperature of the dosimeter is above 0°C and below 62°C (3).
Note 2: The temperature coefficient of dosimeter response is known only in this range (see 5.2). Use outside this range requires determination of the temperature coefficient.  
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 appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.  
1.7 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.

General Information

• Status: Published
• Publication Date: 14-May-2016
• ICS: 17.240 - Radiation measurements
• Technical Committee: E61 - Radiation Processing
• Drafting Committee: E61.02 - Dosimetry Systems

Relations

• Replaces: ASTM ISO/ASTM51205-09 - Standard Practice for Use of a Ceric-Cerous Sulfate Dosimetry System
• Effective Date: 15-May-2016
• Refers: ASTM E668-20 - Standard Practice for Application of Thermoluminescence-Dosimetry (TLD) Systems for Determining Absorbed Dose in Radiation-Hardness Testing of Electronic Devices
• Effective Date: 01-Jul-2020
• Refers: ASTM E170-17 - Standard Terminology Relating to Radiation Measurements and Dosimetry
• Effective Date: 01-Jun-2017
• Refers: ASTM E170-16a - Standard Terminology Relating to Radiation Measurements and Dosimetry
• Effective Date: 01-Oct-2016
• Refers: ASTM E178-16 - Standard Practice for Dealing With Outlying Observations
• Effective Date: 01-Jun-2016
• Refers: ASTM E170-16 - Standard Terminology Relating to Radiation Measurements and Dosimetry
• Effective Date: 15-Feb-2016
• Refers: ASTM E170-15a - Standard Terminology Relating to Radiation Measurements and Dosimetry
• Effective Date: 01-Sep-2015
• Refers: ASTM E170-15 - Standard Terminology Relating to Radiation Measurements and Dosimetry
• Effective Date: 15-Mar-2015
• Refers: ASTM E170-14a - Standard Terminology Relating to Radiation Measurements and Dosimetry
• Effective Date: 15-Oct-2014
• Refers: ASTM E170-14 - Standard Terminology Relating to Radiation Measurements and Dosimetry
• Effective Date: 01-Sep-2014
• Refers: ASTM C912-93(2013) - Standard Practice for Designing a Process for Cleaning Technical Glasses
• Effective Date: 01-Oct-2013
• Refers: ASTM E668-13 - Standard Practice for Application of Thermoluminescence-Dosimetry (TLD) Systems for Determining Absorbed Dose in Radiation-Hardness Testing of Electronic Devices
• Effective Date: 01-Jan-2013
• Refers: ASTM E668-10 - Standard Practice for Application of Thermoluminescence-Dosimetry (TLD) Systems for Determining Absorbed Dose in Radiation-Hardness Testing of Electronic Devices
• Effective Date: 01-Jun-2010
• Refers: ASTM E170-10 - Standard Terminology Relating to Radiation Measurements and Dosimetry
• Effective Date: 01-Jun-2010
• Refers: ASTM E925-09 - Standard Practice for Monitoring the Calibration of Ultraviolet-Visible Spectrophotometers whose Spectral Slit Width does not Exceed 2 nm
• Effective Date: 01-Oct-2009

Overview

ASTM ISO/ASTM 51205-17, titled "Standard Practice for Use of a Ceric-Cerous Sulfate Dosimetry System," provides essential guidance for the preparation, use, and calibration of the ceric-cerous sulfate dosimetry system to measure absorbed dose to water when exposed to ionizing radiation. This standard, developed by ASTM and adhering to internationally recognized principles, ensures accurate dosimetry in radiation processing environments. The ceric-cerous system, based on the reduction of ceric ions to cerous ions in an acidic aqueous solution under radiation exposure, enables reliable, traceable measurements for both reference and routine applications.

Key Topics

• Dosimetry System Description
  The ceric-cerous dosimetry system comprises dosimeter solutions (ceric sulfate and cerous sulfate in sulfuric acid), typically sealed in glass ampoules, and suitable analytical instrumentation (spectrophotometer or potentiometer).

• Measurement Methods
  This practice covers two principal readout procedures:

  • Spectrophotometric: Measures the decrease in optical absorbance at a specified UV wavelength.
  • Potentiometric: Measures the change in electropotential in a specialized electrochemical cell.

• Scope of Application

  • Suitable for measurement of absorbed doses to water from 0.5 kGy to 50 kGy (5 × 10² to 5 × 10⁴ Gy).
  • Applicable to gamma radiation, X-radiation/bremsstrahlung, and high energy electrons.
  • Operates within dose rates not exceeding 1 × 10⁶ Gy/s and in the temperature range of 0°C to 62°C.
  • Energy thresholds: >0.6 MeV (gamma), ≥2 MeV (bremsstrahlung electrons), >8 MeV (electron beams).

• Calibration and Quality Assurance
  Calibration must be traceable to national or international standards, utilizing ISO/IEC 17025-accredited laboratories. Regular performance checks of analytical equipment and dosimeter solutions are required for continued accuracy and comparability.

• Influence Quantities and Interferences

  • The system's dose response is temperature-dependent and influenced by initial cerous ion concentration.
  • Sensitivity to organic and chemical impurities necessitates stringent solution preparation and handling.
  • Glassware cleanliness and water purity are critical for consistent dosimeter response.

Applications

• Radiation Processing
  The ceric-cerous sulfate dosimetry system provides reliable absorbed dose measurements in water, essential for:

  • Validation of industrial sterilization and food irradiation processes.
  • Calibration and performance assessment of irradiation equipment.
  • Quality assurance in radiation processing facilities.

• Reference and Routine Dosimetry

  • Acts as a reference standard dosimetry system for establishing traceable absorbed dose measurements.
  • Supports routine monitoring where high accuracy and repeatability are required.
  • Functions as a transfer standard to compare dosimetry systems between laboratories.

• Regulatory Compliance
  Adoption of this standard assists facilities in meeting requirements for traceability, calibration, and documentation as defined by international guidelines and national regulatory bodies.

Related Standards

• ISO/ASTM 52628: Practice for dosimetry in radiation processing - essential companion for implementation.
• ISO/ASTM 51261: Guide for selection and calibration of routine dosimetry systems.
• ASTM E170: Terminology relating to radiation measurements and dosimetry.
• ISO/IEC 17025: General requirements for the competence of testing and calibration laboratories.
• ASTM E666, E668: Practices for calculating absorbed dose and dosimetry in related environments.
• ICRU Reports 14, 34, 35, 37, 80: Reference materials for methodologies and dose measurement principles.

By following ASTM ISO/ASTM 51205-17, organizations ensure precise, traceable, and internationally recognized measurement of absorbed dose in radiation processing using the ceric-cerous sulfate dosimetry system. This practice underpins critical quality assurance, calibration, and regulatory compliance activities across a wide range of radiation applications.

Standards Content (Sample)

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
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.
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
(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-
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
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). DOI:10.1520/ISOASTM51205-17. www.astm.org, or contact ASTM Customer Service at [e-mail]. For
Theboldfacenumbersinparenthesesrefertothebibliographyattheendofthis Annual Book of ASTM Standardsvolume information, refer to the standard’s
standard. Document Summary page on the ASTM website.
© ISO/ASTM International 2018 – All rights reserved
ISO/ASTM 51205:2017(E)
Ultraviolet-Visible Spectrophotometers 3.1.2 ceric-cerous dosimeter—specially prepared solution
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-
where the radiation-induced changes in electropotential or
tems for Radiation Processing
optical absorbance of the solution are related to absorbed dose
51707Guide for Estimation of Measurement Uncertainty in
to water.
Dosimetry for Radiation Processing
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
2.3 ISO Standards:
solution:
12749-4Nuclear energy – Vocabulary – Part 4: Dosimetry
A
λ
for radiation processing ε 5 (1)
m
d·c
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,
¯
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¯
General Concepts and Associated Terms
−1
SI unit: mol J
2.6 International Commission on Radiation Units and Mea-
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
ICRU Report 35Radiation Dosimetry: Electron Beams with 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
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
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.
DocumentproducedbyWorkingGroup2oftheJointCommitteeforGuidesin
Metrology (JCGM WG2), Available free of charge at the BIPM website (http:// 5. Effect of influence quantities
www.bipm.org).
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 2018 – All rights reserved
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
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
theprimesourceofcontamination.Double-distilledwaterfrom
6.1 The ceric-cerous dosimetric response is sensitive to
impurities, particularly organic impurities. Even in trace coupled all-glass and silica stills or water from a high-quality
commercial purification unit capable of achieving Total Oxi-
quantities, impurities can cause a detectable change in the
observed response (9). Organic materials should not be used dizable Carbon (T.O.C.) content below 5 ppb should be used.
Use of deionized water is not recommended.
for any component in contact with the solution unless they
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].
2 4 3 2
7.2 Potentiometric Method—An electrochemical cell, simi-
lar to that described in Annex A1, should be used (see Fig.
A1.1). The electropotential across the cell should be measured
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.
© ISO/ASTM International 2018 – All rights reserved
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-
sirable chemical change in the dosimetric solution remaining
High Range Low Range
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
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
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,
10.2.2 When the ceric-cerous dosimeter is used in a routine
c = actual concentration of the ceric-sulfate stock solution,
dosimetrysystem,thecalibrationirradiationmaybeperformed
c = actual concentration of the cerous-sulfate stock
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
dosimetersfromalaboratorythathasmeasurementtraceability
sulfuric-acid stock solution.
to nationally or internationally recognized standards.
−3
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
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
© ISO/ASTM International 2018 – All rights reserved
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 .
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)
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 spectrophotometer
cell for about 30 min in order to establish equilibrium across
manufacturer or other scientific laboratory instrument suppli-
the porous junction. For a new batch of dosimeters, or if a cell
ers. Other appropriate wavelength standards are holmium-
has not been used for one or more days, solution should be left
oxidefiltersorsolutions.Formoredetails,seeASTMPractices
in both compartments for at least 16 h to ensure equilibrium
E275, E925, and E958.
across the porous junction.
10.5.3 When the cell is being used for the first time, the
NOTE 8—For example, holmium-oxide solutions in sealed cuvettes are
available as certified wavelength standards (SRM 2034) for use in the filledcellshouldbelefttostandforatleast24hbeforemaking
wavelength region from 240 to 650 nm (12).
any measurements.
10.5.4 If the cell is not going to be used for more than three
10.3.1.2 Check the accuracy of the photometric (absor-
days, drain all solution from the cell. Rinse both the inner and
bance) scale of the spectrophotometer. Certified absorbance
outer compartments three times with purified water, and allow
standard filters or solutions are available for this purpose.
thecelltoairdry.Referto10.5.1and10.5.2beforereusingthe
NOTE 9—Examples of absorbance standards are solutions of various
cell.
concentrations, such as SRM 931d (13) and SRM 935 (14), and metal-
10.5.5 Drain the inner compartment and refill it with the
on-quartz filters, such as SRM 2031 (15,16).
contents of another unirradiated dosimeter.
10.3.2 Digital Voltmeter and Electrochemical Cell Perfor-
10.5.6 Connect the digital voltmeter across the cell. If the
mance:
electropotential, E, is equal to zero (within 60.2 mV), the cell
10.3.2.1 For the potentiometric method, correct perfor-
is ready for use. Read at least three unirradiated dosimeters,
mancecanbedemonstratedbyshowingthattheabsorbeddose
¯
and determine average value E .
obtained from the measurement of dosimeters given known
¯
NOTE 11—If the average electropotential, E , is not equal to zero
absorbeddosesareinagreementwiththegivenabsorbeddoses 0
(greater than 0.2 mV or less than -0.2 mV), rinse cells again with
within the limits of the dosimetry system uncertainty (see
unirradiated dosimetric solution. If still unable to obtain reading within
Section 13).
60.2 mV, confirm that cell is operating satisfactorily by reading dosim-
NOTE 10—This method is only applicable for reference-standard
eters given known doses and confirming that results are within predeter-
dosimetry systems where the long-term stability of the response has been
mined uncertainty limits.
demonstrated and documented.
10.5.7 Expel the unirradiated solution from the outer com-
10.4 Spectrophotometric Measurement:
partment and draw in the solution from each irradiated dosim-
10.4.1 For the spectrophotometric measurement, separate at
eter (ampoule) in turn, starting with the lowest and proceeding
least five dosimeters from the remainder of the batch and do
to
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
ISO/ASTM 51205:2009(E)
ISO/ASTM 51205 − 2017(E)
Standard Practice for
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.
1. Scope
1.1 This practice covers the procedures for preparation, testing, and procedure for using the ceric-cerous sulfate dosimetry
system to determinemeasure absorbed dose (in terms of absorbed dose to water) in materials irradiated by photons (gamma
radiation or X-radiation/bremsstrahlung) or high-energy electrons. 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. It The ceric-cerous dosimeter is classified as a reference–standard dosimetry system (see ISO/ASTM Guidetype 1
dosimeter on the basis 51261). Ceric-cerous dosimeters are also used as transfer–standard dosimeters or routine dosimeters.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 This document 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.
1.5 This practice applies provided the following conditions are satisfied:
2 4 2
1.5.1 The absorbed-dose range is between 0.5 and 50from 5 × 10 kGy to 5 × 10 Gy (1).
6 −1
1.5.2 The absorbed-dose rate is less thandoes not exceed 10 Gy s (1).
1.5.3 For radionuclide gamma-ray sources, the initial photon energy is greater than 0.6 MeV. For bremsstrahlung photons, the
initial 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.
NOTE 1—The lower energy limits are appropriate for a cylindrical dosimeter ampoule of 12-mm diameter. Corrections for dose gradientsgradient across
an ampoule of that diameter or less are not required for photons, but the ampoule may be required for electron beams (2). The ceric-cerous system may
be used at lower energies by employing thinner (in the beam direction) dosimeters.dosimeters (see ICRU Report 35).
1.5.4 The irradiation temperature of the dosimeter is above 0°C and below 62°C (3).
NOTE 2—The temperature dependencecoefficient of dosimeter response is known only in this range (see 4.35.2). Use outside this range requires
determination of the temperature dependence.coefficient.
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 appropriate safety and health practices and determine the applicability of regulatory
limitations prior to use.
1.7 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.
This guidepractice is under the jurisdiction of ASTM Committee E61 on Radiation Processing and is the direct responsibility of Subcommittee E61.02 on Dosimetry
Systems, and is also under the jurisdiction of ISO/TC 85/WG 3.
Current edition approved June 18, 2008. Published June 2009.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 15555:1998(E). The present International Standard ISO/ASTM
51205:2009(E)51205:2017(E) is a major revision of ISO/ASTM 51205-2002(E) which replaced ISO 15555.51205-2009(E). DOI:10.1520/ISOASTM51205-17.
The boldface numbers in parentheses refer to the bibliography at the end of this standard.
© ISO/ASTM International 2017 – All rights reserved
ISO/ASTM 51205:2017(E)
2. Referenced documents
2.1 ASTM Standards:
C912 Practice for Designing a Process for Cleaning Technical Glasses
E170 Terminology Relating to Radiation Measurements and Dosimetry
E178 Practice for Dealing With Outlying Observations
E275 Practice for Describing and Measuring Performance of Ultraviolet and Visible Spectrophotometers
E666 Practice for Calculating Absorbed Dose From Gamma or X Radiation
E668 Practice for Application of Thermoluminescence-Dosimetry (TLD) Systems for Determining Absorbed Dose in
Radiation-Hardness Testing of Electronic Devices
E925 Practice for Monitoring the Calibration of Ultraviolet-Visible Spectrophotometers whose Spectral Bandwidth does not
Exceed 2 nm
E958 Practice for Estimation of the Spectral Bandwidth of Ultraviolet-Visible Spectrophotometers
2.2 ISO/ASTM Standards:
51261 GuidePractice for Selection and Calibration of Routine Dosimetry Systems for Radiation Processing
51707 Guide for Estimation of Measurement Uncertainty in Dosimetry for Radiation Processing
5140052628 Practice for Characterization and Performance of a High-Dose Radiation Dosimetry Calibration LaboratoryDo-
simetry in Radiation Processing
5170752701 Guide for Estimating Uncertainties in Dosimetry for Performance Characterization of Dosimeters and Dosimetry
Systems for Use in Radiation Processing
2.3 ISO Standards:
12749-4 Nuclear energy – Vocabulary – Part 4: Dosimetry for radiation processing
2.4 ISO/IEC Standards:
17025 General Requirements for the Competence of Testing and Calibration Laboratories
2.5 Joint Committee for Guides in Metrology (JCGM) Reports:
JCGM 100:2008, GUM 1995, with minor corrections, Evaluation of measurement data – Guide to the Expression of Uncertainty
in Measurement
JCGM 200:2012 (JCGM 200:2008 with minor revisions),VIM, International Vocabulary of Metrology – Basis and General
Concepts and Associated Terms
2.6 International Commission on Radiation Units and Measurements (ICRU) Reports:
ICRU Report 1410b (NBS Handbook 85) Radiation Dosimetry: X-Rays and Gamma Rays with Maximum Photon Energies
Between 0.6 and 60 MeVPhysical Aspects of Irradiation
ICRU Report 34 The Dosimetry of Pulsed Radiation
ICRU Report 35 Radiation Dosimetry: Electrons Electron Beams with Initial Energies Between 1 and 50 MeV
ICRU Report 3780 Stopping Powers for Electrons and PositronsDosimetry Systems for Use in Radiation Processing
ICRU Report 6085a RadiationFundamental Quantities and Units for Ionizing Radiation
3. Terminology
3.1 Definitions:
3.1.1 calibration—approved laboratory—set of operations under specified conditions, which establishes the relationship
between values indicated by a measuring instrument or measuring system, and the corresponding values realized by standards
traceable to a nationally or internationally recognized laboratory.laboratory that is a recognized national metrology institute, or has
been formally accredited to ISO/IEC 17025, or has a quality system consistent with the requirements of ISO/IEC 17025.
For referenced ASTM and ISO/ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book
of ASTM Standards volume information, refer to the standard’s Document Summary page on the ASTM website.
Available from International Organization for Standardization (ISO), ISO Central Secretariat, BIBC II, Chemin de Blandonnet 8, CP 401, 1214 Vernier, Geneva,
Switzerland, http://www.iso.org.
Document produced by Working Group 1 of the Joint Committee for Guides in Metrology (JCGM WG1), Available free of charge at the BIPM website
(http://www.bipm.org).
Document produced by Working Group 2 of the Joint Committee for Guides in Metrology (JCGM WG2), Available free of charge at the BIPM website
(http://www.bipm.org).
Available from International Commission on Radiation Units and Measurements, 7910 Woodmont Ave., Suite 800, Bethesda, MD 20814, USA.
3.1.1.1 Discussion—
Calibration conditions include environmental and irradiation conditions present during irradiation, storage and measurement of the
dosimeters that are used for the generation of a calibration curve. To achieve stable environmental conditions, it may be necessary
to condition the dosimeters before performing the calibration procedure.A recognized national metrology institute or other
calibration laboratory accredited to ISO/IEC 17025 should be used in order to ensure traceability to a national or international
© ISO/ASTM International 2017 – All rights reserved
ISO/ASTM 51205:2017(E)
standard. A calibration certificate provided by a laboratory not having formal recognition or accreditation will not necessarily be
proof of traceability to a national or international standard.
3.1.2 calibration curve—graphical representation of the dosimetry system’s response function.
3.1.2 ceric-cerous dosimeter—specially prepared solution of ceric sulfate and cerous sulfate in sulfuric acid, individually sealed
in an appropriate container such as a glass ampoule, where the radiation-induced changes in electropotential or optical absorbance
of the solution are related to absorbed dose to water.
3.1.4 measurement quality assurance plan—documented program for the measurement process that ensures that the expanded
uncertainty consistently meets the requirements of the specific application. This plan requires traceability to nationally or
internationally recognized standards.
3.1.3 molar linear absorption coeffıcient, ε —constant relating the spectrophotometric absorbance, A , of an optically absorbing
m λ
molecular species at a given wavelength, λ, per unit pathlength, d, to the molar concentration, c, of that species in solution:
A
λ
ε 5 (1)
m
d·c
2 −1
SI unit: m mol
3.1.3.1 Discussion—
−1 −1
The measurement is sometimes expressed in units of L mol cm .
3.1.6 net absorbance, ΔA—change in measured optical absorbance at a selected wavelength determined as the absolute
difference between the pre-irradiation absorbance, A , and the post-irradiation absorbance, A, as follows:
o
ΔA 5 A 2 A (2)
? o?
3.1.4 radiation chemical yield, G(x)—quotient of n(x) by ε¯, where n(x) is the mean amount of a specified entity, x, produced,
destroyed, or changed by the mean energy, ε, imparted to the matter.
¯
n x
~ !
G x 5 (2)
~ !
¯ε
−1
SI unit: mol J
3.1.5 reference standard dosimetry system—dosimetry system, generally having the highest metrological quality available at a
given location or in a given organization, from which measurements made there are derived.
3.1.6 reference–standard type 1 dosimeter—dosimeter of high metrological quality used as a standard to provide measurements
traceable to measurements made using primary–standard dosimeters.quality, the response of which is affected by individual
influence quantities in a well-defined way that can be expressed in terms of independent correction factors.
3.1.9 response function—mathematical representation of the relationship between dosimeter response and absorbed dose, for a
given dosimetry system.
3.1.10 routine dosimeter—dosimeter calibrated against a primary–, reference–, or transfer–standard dosimeter and used for
routine absorbed-dose measurements.
3.1.11 transfer–standard dosimeter—a dosimeter, often a reference–standard dosimeter suitable for transport between different
locations, used to compare absorbed-dose measurements.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 electropotential, E—difference in potential between the solutions in the two compartments of an electrochemical cell,
measured in millivolts.
3.3 For definitions Definitions of other terms used in this practice that pertain to radiation measurement and dosimetry, refer to
ASTM Terminologydosimetry may be found in E170. Definitions in ISO 12749-4, ASTM Terminology E170 are compatible with
ICRU 60; that document, , ICRU 85a, and VIM; these documents, therefore, may be used as an alternative reference.references.
4. Significance and use
4.1 The ceric-cerous system provides a reliable means for determining absorbed dose to water. It is based on a process of
reduction of ceric ions to cerous ions in acidic aqueous solution by ionizing radiation (1, 4)., ICRU Report 80).
NOTE 3—The ceric-cerous system described in the practice has cerous sulfate added to the initial solution to reduce the effect of organic impurities
and to allow the potentiometric method of measurement. Other systems used for dosimetry include solutions of ceric sulfate or ceric ammonium sulfate
in sulfuric acid without the initial addition of cerous sulfate. These other systems are based on the same process of reduction of ceric ions to cerous ions
but are not included in this practice.
4.2 The dosimeter is a solution of ceric sulfate and cerous sulfate in sulfuric acid in an appropriate container such as a
flame-sealed glass ampoule. The solution indicates a level of absorbed dose by a change (decrease) in optical absorbance at a
© ISO/ASTM International 2017 – All rights reserved
ISO/ASTM 51205:2017(E)
specified wavelength in the ultraviolet region, or a change (increase) in electropotential. A calibrated spectrophotometer is used
to determine the absorbance and a potentiometer, with a specially designed cell, is used to determine the electropotential in
millivolts.
4.3 The dosimeter response has an irradiation temperature dependence since the radiation chemical yield ( G~Ce ! ) depends
on temperature. The dependence of G Ce is approximately equal to −0.2 % per degree Celsius between 0 and 62°C (3, 5, 6). This
~ !
irradiation temperature dependence has a slight dependence on the initial cerous ion concentration (see 10.6.3).
4.4 The absorbed dose to materials other than water when irradiated under equivalent conditions may be calculated. Procedures
for making such calculations are given in ASTM Practices E666 and E668 and ISO/ASTM Guide 51261.
NOTE 4—For a comprehensive discussion of various dosimetry methods applicable to the radiation types and energies discussed in this practice, see
ICRU Reports 14, 34, 35, and 37.
5. Effect of influence quantities
5.1 Guidance on the determination of the performance characteristics of dosimeters and dosimetry systems can be found in
ASTM Guide 52701. The relevant quantities that need to be considered when using the ceric-cerous dosimetry system are given
below.
5.2 The dosimeter response has a temperature dependence during irradiation that is approximately equal to −0.2 % per degree
Celsius between 0 and 62°C (3, 5, 6). This irradiation temperature dependence has a slight dependence on the initial cerous ion
concentration (see 10.6.2).
5.3 The electropotential, E, within the electrochemical cell, has a positive temperature coefficient of 0.33 % per °C between
25°C and 30°C and corrections are required for differences between measurement temperatures and the reference temperature used
during calibration (see 10.5.8)
5.4 No effect of ambient light (even direct sunlight) has been observed on dosimetric solutions in glass ampoules.
5.5 The dosimeter response is dependent on the type and energy of the radiation employed. Since cerium is a heavy element
from the viewpoint of absorption characteristics of gamma radiation, the response of the dosimetric solution for lower energy
degraded radiation during use my be greater than the response in the cobalt-60 radiation during calibration (7). However, studies
in an industrial gamma irradiator indicate that this effect is small (8).
5.6 If the dosimetric solution is prepared as described in this document, and steps are taken to avoid contamination, the
dosimetric solution stored, or sealed, in glass vessels (for example, ampoules) is stable for several years before and after irradiation.
6. Interferences
6.1 The ceric-cerous dosimetric solution response is sensitive to impurities, particularly organic impurities. Even in trace
quantities, impurities can cause a detectable change in the observed response (79). Organic materials shallshould not be used for
any component in contact with the solution unless they have been tested and shown to have no effect. The effect of trace impurities
is minimized by the addition of cerous ions to the solution (810, 911). Water purification methods found to be adequate for use
in preparing ceric-cerous dosimeters are decribed in 7.28.2.
6.2 Undesirable chemical changes in the dosimetric solution can occur if care is not taken during sealing of the ampoules (see
8.79.7).
7. Apparatus
7.1 Spectrophotometric Method—For the analysis of the dosimetric solution, use a high-precision spectrophotometer capable of
measuring absorbance values up to two with an uncertainty of no more than 1 % in the analysis wavelength region from 254 to
320 nm. Use quartz nm should be used. Quartz cuvettes with 10-mm path length should be used for spectrophotometric
measurements of absorbance of the solution.
7.2 Potentiometric Method—Use an An electrochemical cell, similar to that described in Annex A1, should be used (see Fig.
A1.1). Measure the The electropotential across the cell should be measured with a high-precision digital potentiometervoltmeter
that is capable of measuring dc potentials in the range from 1 to 100 mV within an uncertainty of 1 %.
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 ceramic or kaolin
junction, or a fibreglass wick. The inner compartment is always filled with unirradiated solution. The lower compartment is filled with solution transferred
whose response is to be measured (transferred from an irradiated or unirradiated ampoule.ampoule). The electropotential, E, generated between the
platinum electrodes in the two compartments is measured by a digital potentiometer.voltmeter.
7.3 Glassware—Use borosilicate Borosilicate glass or equivalent chemically resistant glass should be used to store the reagents
and the prepared dosimetric solution. Clean all All glassware, except ampoules, should be cleaned using chromic acid cleaning
solution or an equivalent cleaning agent (see ASTM Practice C912). Rinse Glassware should be rinsed at least three times with
double-distilled water. Drypurified water, dried thoroughly and storestored under conditions that will minimize exposure to dust.
© ISO/ASTM International 2017 – All rights reserved
ISO/ASTM 51205:2017(E)
7.4 Glass Ampoules—If required, clean glass ampoules should be cleaned in boiling double-distilled water. Rinsepurified water,
rinsed twice with double-distilled waterpurified water, and oven dry.dried.
NOTE 5—The dosimetric ampoule normally used has a capacity of approximately 2 mL. Quick-break glass ampoules, or Type 1 glass colorbreak
ampoules or equivalent containers, are commonly used. Commercially available ampoules have been found to give reproducible results without requiring
additional cleaning.
8. Reagents
8.1 Analytical reagent grade (or better) chemicals shall be used for preparing all solutions.
8.2 Water quality is very important since it is the major component of the dosimetric solutions, and therefore may be the prime
source of contamination. The water quality is more important for ceric-cerous dosimeters used for measurements in the lower
absorbed-dose range than for those used in the upper absorbed-dose range. For high-range dosimeters double-distilled water
Double-distilled water from coupled all-glass and silica stills can be used. For low-range dosimeters, use triply-distilled water.
Alternatively, use or water from a high-quality commercial purification unit capable of achieving Total Oxidizable Carbon (T.O.C.)
content below 5 ppb. ppb should be used. Use of deionized water is not recommended.
NOTE 6—Double-distilled water distilled from an alkaline potassium permanganate (KMnO ) solution (2 g KMnO plus 5 g sodium hydroxide (NaOH)
4 4
pellets in 2 L of distilled water) has been found to be adequate for routine preparation of the dosimetric solution. High-purity water is commercially
available from some suppliers. Such water labeled HPLC (high-pressure liquid chromatographic) grade is usually sufficiently free from organics to be
used in this practice.
8.3 Do not store purified Purified water used in this practice should not be stored in plastic containers or in containers with
plastic caps or plastic cap liners.
9. Preparation of the dosimeters
9.1 The recommended Recommended concentrations for the ceric-cerous dosimeter to measure for measurement of absorbed
−3 −3
doses from about 5 to 50 kGy (high-range dosimeter) are 15 mmol dm ceric sulfate [Ce(SO ) · 4H O] and 15 mmol dm cerous
4 2 2
sulfate [Ce (SO ) · 8H O]. For measurement of absorbed doses from about 0.5 to 10 kGy (low-range dosimeter), the
2 4 3 2
−3 −3
recommended concentrations are 3 mmol dm [Ce(SO ) · 4H O] and 3 mmol dm [Ce (SO ) · 8H O].
4 2 2 2 4 3 2
9.2 The dosimetric solutions specified in 8.19.1 may be formulated from the following nominal stock solutions: (a) 0.4 mol
−3 −3 −3 −3
dm and 4 mol dm sulfuric acid (H SO ), (b) 0.1 mol dm Ce(SO ) · 4H O, and (c) 0.1 mol dm Ce (SO ) · 8H O.
2 4 4 2 2 2 4 3 2
Procedures for preparing these solutions are given in Annex A2. (Warning—Concentrated sulfuric acid is corrosive and can cause
serious burns. Ceric-cerous solutions are skin irritants. Appropriate precautions should be exercised in handling these materials.)
th
Reagent specifications are available from American Chemical Society, 1115 16 St., Northwest, Washington, DC 20036, USA.
© ISO/ASTM International 2017 – All rights reserved
ISO/ASTM 51205:2017(E)
9.3 Use the following equations to determine the volume in millilitres of each stock solution necessary to prepare 1 L of
dosimetric solution:
High Range Low Range
V 0.015 V 0.003
1 1
5 5 (3)
1000 c 1000 c
1 1
V 0.015 V 0.003
2 2
5 5 (4)
1000 c 1000 c
2 2
V 0.4 V 0.4
3 3
5 5 (5)
1000 2V c 1000 2V c
1 3 1 3
V 51000 2V 2V 2V V 51000 2V 2V 2V (6)
4 1 2 3 4 1 2 3
where:
−3
V = volume of nominal 0.1 mol dm ceric-sulfate stock solution,
−3
V = volume of nominal 0.1 mol dm cerous-sulfate stock solution,
−3
V = volume of nominal 4 mol dm sulfuric-acid stock solution,
V = volume of distilled water,
V = volume of purified water,
c = actual concentration of the ceric-sulfate stock solution,
c = actual concentration of the cerous-sulfate stock solution, and
−3
c = actual concentration of the nominal 4 mol dm sulfuric-acid stock solution.
−3 −3
NOTE 7—If the nominal concentrations of c = c = 0.1 mol dm , and c = 4 mol dm are assumed, then V = V = 150 mL for the high range and
1 2 3 1 2
V = V = 30 mL for the low range; V = 85 mL for the high range and V = 97 mL for the low range. If the concentrations of the various stock solutions
1 2 3 3
are significantly different from the nominal values, then use Eq 4-6 to determine the exact volumes. To prepare a volume of the dosimetric solution other
than 1000 mL, the result of these equations should be multiplied by the ratio of the desired volume in millilitres to 1000 mL.
9.4 Determine all of the volumes given in 8.39.3 using a calibrated graduated cylindervolumetric flask that can be read to within
60.5 mL.
9.5 Transfer the volume of each component of the dosimetric solution into a 1-L or larger glass storage container. Rinse the
graduated cylindervolumetric flask used for measuring V , V , and V by using some portion of the distilledpurified water of V .
1 2 3 4
Stopper the container and shake well. Before use, allow the dosimetric solution to stand for at least five days in the dark.dark
(ICRU 10b).
9.6 Quality control testing of the dosimetric solution prior to ampouling is performed by comparing the measurement of
dosimetric solution parameters, such as ceric-ion concentration, cerous-ion concentration, ceric-ion molar linear absorption
coefficient, radiation chemical yield for the cerous ion, and density with acceptable values. Procedures for performing these
measurements are given in Annex A3. Quality control testing following ampouling is performed by comparing calibration data for
the new dosimeter batch with data obtained from previous batches (see 10.5.310.6.4).
9.7 Prepare dosimeters by filling ampoules with approximately 2 mL of dosimetric solution. Take care not to contaminate the
dosimetric solution with impurities. Exercise care in filling ampoules to avoid depositing solution in the ampoule neck. Subsequent
heating during sealing may cause an undesirable chemical change in the dosimetric solution remaining inside the ampoule neck.
Flame seal the ampoules, exercising care to avoid heating the body of the ampoule during sealing.
9.8 Store dosimeters in a dark place at room temperature (23 6 5°C).(23 6 5°C).
9. Analytical instrument performance
9.1 Spectrophotometer Performance:
9.1.1 Check the wavelength scale of the spectrophotometer. Appropriate wavelength standards are holmium-oxide filters and
solutions. For more details see ASTM Practices E275, E925, and E958.
NOTE 9—For example, holmium-oxide solutions in sealed cuvettes are available as certified wavelength standards (SRM 2034) for use in the
wavelength region from 240 to 650 nm (10).
9.1.2 Check the accuracy of the photometric (absorbance) scale of the spectrophotometer. Certified absorbance standard filters
or solutions are available for this purpose.
NOTE 10—Examples of absorbance standards are solutions of various concentrations, such as SRM 931d (11) and SRM 935 (12), and metal-on-quartz
filters, such as SRM 2031 (13, 14).
© ISO/ASTM International 2017 – All rights reserved
ISO/ASTM 51205:2017(E)
9.1.3 Check the linearity of the absorbance scale of the spectrophotometer as a function of the ceric-ion concentration. This
should be done at the peak of the absorbance spectrum for the ceric ion at 320 nm at a constant temperature, preferably 25°C. The
−3 −3
standardized ceric-sulfate stock solution (0.1 mol dm nominal in 0.4 mol dm H SO ), as described in A2.3, may be used for
2 4
this measurement. The plot of measured absorbance, A, per unit path length versus concentration shall be linear. The slope of the
line gives, ε , the molar linear absorption coefficient.
m
2 −1
NOTE 11—A reference value for ε is 561 m ·mol 6 0.4 % at 320 nm (3).
m
9.2 Potentiometer and Electrochemical Cell Performance:
9.2.1 For the potentiometer method, correct performance can be demonstrated by showing that the readings of dosimeters given
known absorbed doses are in agreement with the expected readings within the limits of the dosimetry system uncertainty (see
Section 13).
NOTE 12—This method is only applicable for reference-standard dosimetry systems where the long-term stability of the response has been
demonstrated and documented.
10. Calibration of the dosimetry system
10.1 The dosimetry system shall be calibrated prior to use and at intervals thereafter Prior to use, the dosimetry system
(consisting of a specific batch of dosimeters and specific measurement instruments) shall be calibrated in accordance with the
user’s documented procedure that specifies details of the calibration process and quality assurance requirements. Calibration
requirements are given in ISO/ASTM GuideThis calibration shall be 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 in
ISO/ASTM Practice 51261.
10.2 Calibration Irradiation of Dosimeters—Irradiation is a critical component of the calibration of the dosimetry system.
Calibration irradiations shall be performed at a national or accredited laboratory using criteria specified in ISO/ASTM Practice
51400.
10.2.1 When the ceric-cerous dosimeter is used in a reference standard dosimetry system, calibration irradiations shall be
performed at an approved laboratory, as defined in 3.1.1.
10.2.2 When the ceric-cerous dosimeter is used in a routine dosimetry system, the calibration irradiation may be performed in
accordance with 10.2.1, or at a production or research irradiation facility together with reference- or transfer-standard dosimeters
from a laboratory that has measurement traceability to nationally or internationally recognized standards.
10.2.3 Specify the calibration dose in terms of absorbed dose to water.
10.2.4 When For calibration with photons, the ceric-cerous dosimeter is used as a routine dosimeter, the calibration irradiation
may be performed by irradiating the dosimeters at shall be irradiated (a) a national or accredited laboratory using criteria specified
in ISO/ASTM Practice 51400, (b) an in-house calibration facility that provides an absorbed dose (or an absorbed-dose rate) having
measurement traceability to nationally or internationally recognized standards, or (c) a production irradiator under actual
production irradiation conditions, together with reference– or transfer–standard dosimeters that have measurement traceability to
nationally or internationally recognized standards.under conditions that approximate electron equilibrium.
10.2.5 The dosimeter shall be calibrated in a radiation field of the same type and energy as that in which it is to be used, unless
evidence is available to demonstrate equivalence of response. If not, a correction factor has to be applied and its associated
uncertainty must be added to the uncertainty budget.
10.2.6 Control (or monitor) the temperature of the dosimeters during irradiation. Calculate or measure the mean irradiation
temperature of each dosimeter to an accuracy of 62°C, or better.
10.2.7 Use a set of at least three dosimeters for each absorbed dose value.
10.2.8 Irradiate these sets of dosimeters to at least five known dose values for each factor of ten span of absorbed doses covering
the range of utilization in order to determine the calibration curve for the dosimetry system.
10.3 Measurement Instrument Calibration and Performance Verification—For the calibration of instruments (spectrophotometer
or multimeter), digital voltmeter), and for the verification of instrument performance between calibrations, see ISO/ASTM Guide
51261Practice 51261 and/or instrument-specific manuals.
10.3.1 Spectrophotometer Performance:
10.3.1.1 Check the wavelength scale of the spectrophotometer and establish its accuracy. The emission spectrum from a
low-pressure mercury arc lamp can be used for this purpose. Such a lamp may be obtained from the spectrophotometer
manufacturer or other scientific laboratory instrument suppliers. Other appropriate wavelength standards are holmium-oxide filters
or solutions. For more details, see ASTM Practices E275, E925, and E958.
NOTE 8—For example, holmium-oxide solutions in sealed cuvettes are available as certified wavelength standards (SRM 2034) for use in the
wavelength region from 240 to 650 nm (12).
10.3.1.2 Check the accuracy of the photometric (absorbance) scale of the spectrophotometer. Certified absorbance standard
filters or solutions are available for this purpose.
© ISO/ASTM International 2017 – All rights reserved
ISO/ASTM 51205:2017(E)
NOTE 9—Examples of absorbance standards are solutions of various concentrations, such as SRM 931d (13) and SRM 935 (14), and metal-on-quartz
filters, such as SRM 2031 (15,16).
10.3.2 Digital Voltmeter and Electrochemical Cell Performance:
10.3.2.1 For the potentiometric method, correct performance can be demonstrated by showing that the absorbed dose obtained
from the measurement of dosimeters given known absorbed doses are in agreement with the given absorbed doses within the limits
of the dosimetry system uncertainty (see Section 13).
NOTE 10—This method is only applicable for reference-standard dosimetry systems where the long-term stability of the response has been
demonstrated and documented.
10.4 Spectrophotometric Measurement:
10.4.1 For the spectrophotometric measurement, separate at least five dosimeters from the remainder of the batch and do not
irradiate them. Use them in determining the average absorbance, A¯ .
o0
10.4.2 For spectrophotometric measurement of both unirradiated and irradiated dosimeters, dilute open dosimeter ampoules
(break at neck if quick-break ampoules are used). Dilute high-range dosimetric solutions by a factor of 100 and low-range
dosimetric solutions by a factor of 50.
10.4.2.1 Pipette 0.25 mL of high-range dosimetric solution or 0.5 mL of low-range dosimetric solution into a clean, dry 25-mL
volumetric flask.
−3 −3
10.4.2.2 Rinse the pipette with 0.4 mol dm H SO into the flask and make up to volume with 0.4 mol dm H SO .
2 4 2 4
10.4.2.3 Stopper the 25-mL flask, and mix well.
10.4.3 Transfer an appropriate amount into a quartz spectrophotometric cuvette (sample cell) from the 25-mL volumetric flask.
10.4.4 Read the absorbance, A, in the spectrophotometer at 320 nm.nm in a 1 cm path length cuvette.
10.4.5 Calculate the mean absorbance of the unirradiated dosimeters, A¯ . Calculate the net absorbance, ΔA, for each irradiated
o
dosimeter:Calculations:
¯
ΔA 5 A 2 A (8)
o
10.4.5.1 Calculate the mean absorbance of the unirradiated dosimeters, A¯ .
10.4.5.2 Calculate the net absorbance, ΔA, for each irradiated dosimeter:
¯
ΔA 5 A 2 A (7)
10.5 Potentiometric Measurement:
10.5.1 Place contents of an unirradiated dosimeter (ampoule) into both compartments of the electrochemical cell. See Annex
A1 for a description of the electrochemical cell.
10.5.2 Allow the solution to remain in the electrochemical cell for about 30 min in order to establish equilibrium across the
porous junction. For a new batch of dosimeters, or if a cell has not been used for one or more days, solution should be left in both
compartments for at least 16 h to ensure equilibrium across the porous junction.
10.5.3 When the cell is being used for the first time, the filled cell should be left to stand for at least 24 h before making any
measurements.
10.5.4 If the cell is not going to be used for more than three days, drain all solution from the cell. Rinse both the inner and outer
compartments three times with distilledpurified water, and allow the cell to air dry. Refer to 10.5.1 and 10.5.2 before reusing the
cell.
10.5.5 Drain the inner compartment and refill it with the contents of another unirradiated dosimeter.
10.5.6 Connect the digital potentiometervoltmeter across the cell. If the electropotential, E, is equal to zero (within 60.2 mV),
the cell is ready for use. Read at least three unirradiated dosimeters, and determine average value E¯ .
o0
NOTE 11—If the average electropotential, E¯ , is not equal to zero (greater than 0.2 mV or less than -0.2 mV), rinse cells again with unirradiated
dosimetric solution. If still unable to obtain reading within 60.2 mV, confirm that cell is operating satisfactorily by reading dosimeters given known doses
and confirming that results are within predetermined uncertainty limits.
10.5.7 Expel the unirradiated solution from the outer compartment and draw in the solution from each irradiated dosimeter
(ampoule) in turn, starting with the lowest and proceeding to the highest absorbed dose. In each case, before measuring the
electropotential for any particular dosimeter, rinse the cell by drawing in a little less than half of that dosimeter’s solution in order
to reduce the effects of the previous dosimeter. Expel the rinse solution into a waste container, and then draw in sufficient solution
from that remaining in the dosimeter ampoule to fully cover the porous junction.
NOTE 12—Inadequate rinsing of the cell between dosimetric solutions can lead to errors due to solution carryover. If the approximate absorbed doses
are known, read the dosimeters that received similar absorbed doses together to minimize the errors from this effect.
10.5.8 Read the electropotential, E, in millivolts, across the cell for each dosimeter after temperature equilibrium is established
within the between the dosimetric solution within the cell and the room temperature near the cell. Subtract the average
electropotential, E¯ , to determine ΔΔE,E, the net electropotential value. Measure the readout temperature near the electrochemi-
o0
cal cell, and apply correction for this temperature.
Electrochemical cells can be obtained from MDS Nordion, 447 March Road, Ottawa, Ontario, Canada K2K 1X8.
© ISO/ASTM International 2017 – All rights reserved
ISO/ASTM 51205:2017(E)
NOTE 13—The electropotential, E, within the electrochemical cell, has a positive temperature coefficient of 0.33 % per °C between 2525°C and 30°C
(810).
10.6 Analysis:
10.6.1 Obtain a response functioncalibration curve for ΔA or ΔE as a function of the absorbed dose, D. Fit the data by means
of a least-squares method with an appropriate analytical form that provides a best fit to the data. The For example, the data for
these ceric-cerous dosimeters should fit can be fitted to a third or fourth order polynomial of the form:
2 3 4
v 5 b 1b D1b D 1b D 1b D (8)
0 1 2 2 4
where:
v = ΔA or ΔE,
b = 0 for third order polynomial, b ≠ 0 for fourth order polynomial.
4 4
NOTE 14—Computer software is available commercially for performing least-squares fits of data with polynomials or other analytical forms. Further
information on mathematical methods for handling calibration data is given in ISO/ASTM GuidePractice 5170751261. Appendix A2.
10.6.2 The inverse of the response function determined in 10.6.1 will provide the calibration–temperature dose for irradiations
performed at the temperature, T , used for the calibration irradiations.
c
10.6.2 The irradiation temperature dependence of the radiation chemical yield G~Ce ! varies with the initial cerous ion
concentration (3). The variation of G Ce with temperature, T(°C), for the high range and low range solutions is given by the
~ !
following equations:
where:
31 27
G Ce 5 2.33544 2 0.0052 3T 31.036 310 high range (9)
~ ! ~ ! ~ !
T
31 27
G Ce 5 2.42452 2 0.0052 3T 31.036 310 low range (10)
~ ! ~ ! ~ !
T
10.6.3 The dosimeter response for the same absorbed dose is approximately inversely proportional to G Ce over the
~ !
absorbed-dose range for the solution. For irradiations at an effective irradiation temperature, T , correct the absorbed dose by the
eff
31 31
ratio G~Ce ! /G~Ce ! ., where T is the irradiation temperature during calibration.
T T c
c eff
10.6.4 For quality control, compare the net absorbances or net electropotentials determined for a given calibration with the
results obtained from previous batches. Agreement should be within 3 % if the dosimetric solutions were properly prepared and
all associated analysis equipment was properly calibrated.
10.6.5 Estimate the component of uncertainty that can be evaluated by statistical methods (Type A) of the individual dosimeter
results The reproducibility (precision) for the individual dosimeter response values, estimated from the results of replicate
measurements at a given absorbed-dose level. Type A uncertainty level provides a measure of acceptable performance of the
dosimetry system. For the high-range dosimeter, the Type A uncertainty, reproducibility, expressed as one standard deviation,
should not exceed 0.005 absorbance units for an optical pathlength of 10 mm or 2 % of the electropotential value. For the
low-range dosimeter, the Type A uncertainty reproducibility should not exceed 0.010 absorbance units or 2 % of the
electropotential value. Suspected data outliers should be tested using statistical procedures, such as those found in ASTM Practice
E178.
10.7 Alternative Method for Determining Absorbed Dose—If the procedures for quantifying dosimetric solution parameters
given in Annex A3 are carried out, approximate values for the absorbed dose can be obtained from analytical functions.
10.7.1 For spectrophotometric readings, calculate an approximate value for the absorbed dose, D , in grays, using the following
s
equation:
f·ΔA
D 5 (12)
s 31
G~Ce !·ε ·ρ·d
m
where:
f = dilution factor for the irradiated dosimeters,
ΔA = change in absorbance of irradiated dosimeter,
3+ 3+
G(Ce ) = average value for G(Ce ) determined from Eq A3.9,
2 −1
ε = molar-linear absorption coefficient (m mol ),
m
−3
ρ = density of the dosimetric solution, kg m , and
d = path length of spectrophotometer cell, m.
10.7.2 For potentiometric readings, calculate an approximate value for the absorbed dose, D , in grays using the following
p
equation:
10 c 1c
4 5
D 5 c 2 (13)
ρ 31 4
ρG~Ce ! c ΔE
F S DG
11 antilog
c 59.16
© ISO/ASTM International 2017 – All rights reserved
ISO/ASTM 51205:2017(E)
where:
−3
ρ = density of the dosimetric solution, kg m ,
3+ 3+
G(Ce ) = average value for G(Ce ) determined from Eq A3.11,
ΔE = electropotential minus average electropotential for unirradiated dosimeters, and
−3
c andc = concentrations of the ceric and cerous ions in the unirradiated dosimetric solutions, respectively, mol dm .
4 5
10.7.3 Determine the relationship for the calculated absorbed doses as a function of the absorbed-dose values used for the
calibration irradiations. The function describing this relationship may be used for the determination of the absorbed dose.
NOTE 16—The calculated absorbed dose values should be close to the absorbed dose values used for the calibration irradiations, providing a good fit
to a low order (first to third order) polynomial. If the calculated absorbed dose values differ by more than the expanded uncertainty with a coverage factor
k=2 from the absorbed-dose values used for the calibration irradiations, there is an indication of possible contamination of the solution, or some other
problem that needs to be resolved.
11. Application of dosimetry system
11.1 For use as a transfer-standard dosimeter, use a minimum of two dosimeters should be used for each absorbed-dose
measurement. The number of dosimeters required for the measurement of absorbed dose on or within a material is determined by
the estimated uncertainty ofreproducibility associated with the dosimetry system and the required measurement uncertainty
associated with the application. Appendix X3 of ASTM Practice E668 describes a statistical method for determining this number.
11.2 Use the The irradiation and measurement procedures described in accordance with Section 10. for the calibration of the
dosimetry system should also be followed when performing dosimetry with the ceric-cerous dosimeters.
11.3 Determine the The absorbed dose to water is determined from the net absorbance values or net electropotential values and
the calibration curve.
NOTE 15—The absorbed dose to materials other than water irradiated under equivalent conditions may be calculated using the procedures given in
ASTM Practices E666 and E668.
11.4 Record Requirements for recording the calculated absorbed dose values and all other relevant data asare outlined in Section
12.
12. Minimum documentation requirements
12.1 Calibration of the Dosimetry System: Calibration:
12.1.1 Record the dosimeter type and batch number (code).
12.1.2 Record or reference the date, irradiation temperature, temperature variation (if any), absorbed-dose range, radiation
source, and associated instrumentation used to measure the dosimeter response.analyze the dosimeters, measurement date, and the
temperature during electropotential measurement for each dosimeter.
12.2 Application:
12.2.1 Record the date of irradiation and temperature of dosimeter during irradiation, temperature variation (if any),
measurement date, and the date and temperature of absorbancetemperature during electropotential measurement for each
dosimeter.
12.2.2 Record or reference the radiation source type and characteristics.
12.2.3 Record the absorbance or electropotential, net
...