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).
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 specified wavelength in the ultraviolet region, or a change (increase) in electropotential.Acalibrated 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~Ce31! )depends on temperature. The dependence of G~Ce31! 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 E 666 and E 668 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, ...
SCOPE
1.1 This practice covers the preparation, testing, and procedure for using the ceric-cerous sulfate dosimetry system to measure absorbed dose in 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 is classified as a reference standard dosimetry system (see ISO/ASTM Guide 51261). Ceric-cerous dosimeters are also used as transfer-standard dosimeters or routine dosimeters.
1.2 This practice describes both the spectrophotometric and the potentiometric readout procedures for the ceric-cerous systems.
1.3 This practice applies only to γ rays, X rays, and high energy electrons.
1.4 This practice applies provided the following are satisfied:
1.4.1 The absorbed-dose range shall be between 5 102 and 5 104 Gy (1).
1.4.2 The absorbed-dose rate shall be less than 10 6 Gy/s (1).
1.4.3 For radionuclide gamma-ray sources, the initial photon energy shall be greater than 0.6 MeV. For bremsstrahlung photons, the initial energy of the electrons used to produce the bremsstrahlung photons shall be equal to or greater than 2 MeV. For electron beams, the initial electron energy shall be greater than 8 MeV.
Note 1—The lower energy limits are appropriate for a cylindrical dosimeter ampoule of 12-mm diameter. Corrections for dose gradients across an ampoule of that diameter or less are not required for photons, but may be required for electron beams (2). The ceric-cerous system may be used at lower energies by employing thinner (in the beam direction) dosimeter containers (see ICRU Report 35).
1.4.4 The irradiation temperature of the dosimeter shall be between 0 and 62°C (3).
Note 2—The temperature coefficient of dosimeter response is known only in this range. For use outside this range, the dosimetry system should be calibrated for the required range of irradiation temperatures.
1.5 This stan...

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Publication Date
21-Jan-2002
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Drafting Committee
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ISO/ASTM 51205:2009(E)
Standard Practice for
1
Use of a Ceric-Cerous Sulfate Dosimetry System
This standard is issued under the fixed designation ISO/ASTM 51205; the number immediately following the designation indicates the
year of original adoption or, in the case of revision, the year of last revision.
used at lower energies by employing thinner (in the beam direction)
1. Scope
dosimeters.
1.1 This practice covers the procedures for preparation,
1.3.4 The irradiation temperature of the dosimeter is above
testing, and using the ceric-cerous sulfate dosimetry system to
0°C and below 62°C (3).
determine absorbed dose (in terms of absorbed dose to water)
NOTE 2—The temperature dependence of dosimeter response is known
in materials irradiated by photons (gamma radiation or
only in this range (see 4.3). Use outside this range requires determination
X-radiation/bremsstrahlung)orhigh-energyelectrons.Thesys-
of the temperature dependence.
tem consists of a dosimeter and appropriate analytical instru-
1.4 This standard does not purport to address all of the
mentation. For simplicity, the system will be referred to as the
safety concerns, if any, associated with its use. It is the
ceric-cerous system. It is classified as a reference–standard
responsibility of the user of this standard to establish appro-
dosimetrysystem(seeISO/ASTMGuide51261).Ceric-cerous
priate safety and health practices and determine the applica-
dosimeters are also used as transfer–standard dosimeters or
bility of regulatory limitations prior to use.
routine dosimeters.
2. Referenced documents
1.2 This practice describes both the spectrophotometric and
3
the potentiometric readout procedures for the ceric-cerous
2.1 ASTM Standards:
system.
C912Practice for Designing a Process for Cleaning Techni-
cal Glasses
1.3 This practice applies provided the following conditions
E170Terminology Relating to Radiation Measurements and
are satisfied:
Dosimetry
1.3.1 The absorbed-dose range is between 0.5 and 50 kGy
2
E178Practice for Dealing With Outlying Observations
(1).
6 −1
E275PracticeforDescribingandMeasuringPerformanceof
1.3.2 The absorbed-dose rate is less than 10 Gy s (1).
Ultraviolet and Visible Spectrophotometers
1.3.3 For radionuclide gamma-ray sources, the initial pho-
E666Practice for CalculatingAbsorbed Dose From Gamma
ton energy is greater than 0.6 MeV. For bremsstrahlung
or X Radiation
photons, the energy of the electrons used to produce the
E668 Practice for Application of Thermoluminescence-
bremsstrahlung photons is equal to or greater than 2 MeV. For
Dosimetry (TLD) Systems for Determining Absorbed
electron beams, the initial electron energy is greater than 8
DoseinRadiation-HardnessTestingofElectronicDevices
MeV.
E925Practice for Monitoring the Calibration of Ultraviolet-
NOTE 1—The lower energy limits are appropriate for a cylindrical
Visible Spectrophotometers whose Spectral Bandwidth
dosimeter ampoule of 12-mm diameter. Corrections for dose gradients
does not Exceed 2 nm
acrossanampouleofthatdiameterorlessarenotrequiredforphotons,but
E958Practice for Estimation of the Spectral Bandwidth of
may be required for electron beams (2). The ceric-cerous system may be
Ultraviolet-Visible Spectrophotometers
3
2.2 ISO/ASTM Standards:
1 51261Guide for Selection and Calibration of Dosimetry
This guide is under the jurisdiction of ASTM Committee E61 on Radiation
Systems for Radiation Processing
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.
51400Practice for Characterization and Performance of a
Current edition approved June 18, 2008. Published June 2009. Originally
High-Dose Radiation Dosimetry Calibration Laboratory
published as ASTM E1205–88. Last previous ASTM edition E1205–99. ASTM
E1205–93 was adopted by ISO in 1998 with the intermediate designation ISO
3
15555:1998(E). The present International Standard ISO/ASTM 51205:2009(E) is a For referenced ASTM and ISO/ASTM standards, visit the ASTM website,
major revision of ISO/ASTM 51205-2002(E) which replaced ISO 15555. www.astm.org, or contact ASTM Customer Service at service@astm.org. For
2
Theboldfacenumbersinparenthesesrefertothebibliographyattheendofthis Annual Book of ASTM Standards volume information, refer to the standard’s
standard. Document Summary page on the ASTM website.
© ISO/ASTM International 2017 – All rights reserved
1

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ISO/ASTM 51205:2009(E)
51707Guide for Estimating Uncertainties in Dosimetry for difference between the pre-irradiation absorbance, A , and the
o
Radiation Processing post-irradiation absorbance, A, as follows:
2.3 International Commission on Radiation Units and Mea-
∆A 5 A 2 A (2)
? o?
4
surements (ICRU) Reports:
3.1.7 radiation chemical yield, G(x)—quotient
...

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