ISO/ASTM 51401:2002

Practice for use of a dichromate dosimetry system

ISO/ASTM 51401 covers the preparation, testing, and procedure for using the acidic aqueous silver dichromate dosimetry system to measure absorbed doses in water when exposed to ionizing radiation. The system consists of a dosimeter and appropriate analytical instrumentation. For simplicity, the system is referred to as the dichromate system and is classified as a reference standard dosimetry system. This International Standard describes the spectrophotometric analysis procedures for the dichromate system. It applies only to gamma-rays, X-rays and high energy electrons provided the following conditions are satisfied: the absorbed dose range is from 2 times 103 Gy to 5 times 10 4 Gy; the absorbed dose rate does not exceed 600 Gy/pulse with a pulse repetition rate not exceeding 12,5 Hz, or does not exceed an equivalent dose rate of 7,5 kGy/s from continuous sources; 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; the irradiation temperature of the dosimeter is above 0 °C and below 80 °C.

Pratique de l'utilisation d'un système de mesure dosimétrique au dichromate

General Information

• Status: Withdrawn
• Publication Date: 17-Apr-2002
• Withdrawal Date: 17-Apr-2002
• ICS: 17.240 - Radiation measurements
• Technical Committee: ISO/TC 85 - Nuclear energy, nuclear technologies, and radiological protection
• Drafting Committee: ISO/TC 85 - Nuclear energy, nuclear technologies, and radiological protection
• Current Stage: 9599 - Withdrawal of International Standard
• Completion Date: 18-Aug-2003

Relations

• Revised: ISO/ASTM 51401:2003 - Practice for use of a dichromate dosimetry system
• Effective Date: 15-Apr-2008
• Revises: ISO 15561:1998 - Practice for use of a dichromate dosimetry system
• Effective Date: 15-Apr-2008

Standards Content (Sample)

INTERNATIONAL ISO/ASTM
STANDARD 51401
First edition
2002-03-15
Practice for use of a dichromate
dosimetry system
Pratique de l’utilisation d’un système dosimétrique au dichromate
Reference number
ISO/ASTM 51401:2002(E)
© ISO/ASTM International 2002

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ISO/ASTM 51401:2002(E)
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ii © ISO/ASTM International 2002 – All rights reserved

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ISO/ASTM 51401:2002(E)
Contents Page
1 Scope . 1
2 Referenced documents . 1
3 Terminology . 2
4 Significance and use . 2
5 Interferences . 2
6 Apparatus . 3
7 Reagents . 3
8 Preparation of dosimeters . 3
9 Spectrophotometer calibration . 3
10 Calibration procedures . 4
11 Application of dosimetry system . 5
12 Minimum documentation requirements . 5
13 Measurement uncertainty . 6
14 Keywords . 6
Bibliography . 6
Figure 1 Relative response of dichromate dosimeter as a function of irradiation temperature. . 3
Figure 2 Response of high-range dosimeter as a function of absorbed dose in water. . 5
Figure 3 Response of the low-range dosimeter as a function of absorbed dose in water. . 5
Table 1 Effect of irradiation temperature on dosimeter response . 2
Table 2 Typical dichromate calibration data . 5
© ISO/ASTM International 2002 – All rights reserved iii

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ISO/ASTM 51401:2002(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
Draft International Standards adopted by the technical committees are circulated to the member bodies for
voting. Publication as an International Standard requires approval by at least 75% of the member bodies
casting a vote.
ASTM International is one of the world’s largest voluntary standards development organizations with global
participation from affected stakeholders. ASTM technical committees follow rigorous due process balloting
procedures.
A pilot project between ISO and ASTM International has been formed to develop and maintain a group of
ISO/ASTM radiation processing dosimetry standards. Under this pilot project, ASTM Subcommittee E10.01,
Dosimetry for Radiation Processing, is responsible for the development and maintenance of these dosimetry
standards with unrestricted participation and input from appropriate ISO member bodies.
Attention is drawn to the possibility that some of the elements of this International Standard may be the subject
of patent rights. Neither ISO nor ASTM International shall be held responsible for identifying any or all such
patent rights.
International Standard ISO/ASTM 51401 was developed by ASTM Committee E10, Nuclear Technology and
Applications, through Subcommittee E10.01, and by Technical Committee ISO/TC 85, Nuclear Energy.
iv © ISO/ASTM International 2002 – All rights reserved

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ISO/ASTM 51401:2002(E)
Standard Practice for
1
Use of a Dichromate Dosimetry System
This standard is issued under the fixed designation ISO/ASTM 51401; 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 1.5 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
1.1 This practice covers the preparation, testing, and proce-
responsibility of the user of this standard to establish appro-
dure for using the acidic aqueous silver dichromate dosimetry
priate safety and health practices and determine the applica-
system to measure absorbed dose in water when exposed to
bility of regulatory limitations prior to use. Specific precau-
ionizing radiation. The system consists of a dosimeter and
tionary statements are given in Note 7.
appropriate analytical instrumentation. For simplicity, the sys-
tem will be referred to as the dichromate system. It is classified
2. Referenced Documents
as a reference standard dosimetry system (see ISO/ASTM
2.1 ASTM Standards:
Guide 51261).
C 912 Practice for Designing a Process for Cleaning Tech-
1.2 This practice describes the spectrophotometric analysis
3
nical Glasses
procedures for the dichromate system.
E 170 Terminology Relating to Radiation Measurements
1.3 This practice applies only to g-rays, X rays, and high
4
and Dosimetry
energy electrons.
E 177 Practice for Use of the Terms Precision and Bias in
1.4 This practice applies provided the following conditions
5
ASTM Test Methods
are satisfied:
5
3 4
E 178 Practice for Dealing with Outlying Observations
1.4.1 The absorbed dose range is from 2 3 10 to 5 3 10
E 275 Practice for Describing and Measuring Performance
Gy.
of Ultraviolet, Visible and Near Infrared Spectrophotom-
1.4.2 The absorbed dose rate does not exceed 600 Gy/pulse
6
eters
with a pulse repetition rate not to exceed 12.5 Hz, or does not
5
E 456 Terminology Relating to Quality and Statistics
exceed an equivalent dose rate of 7.5 kGy/s from continuous
2 E 666 Practice for Calculating Absorbed Dose from Gamma
sources (1).
4
or X-Radiation
1.4.3 For radionuclide gamma-ray sources, the initial pho-
E 668 Practice for Application of Thermoluminescence Do-
ton energy shall be greater than 0.6 MeV. For bremsstrahlung
simetry (TLD) Systems for Determining Absorbed Dose in
photons, the initial energy of the electrons used to produce the
4
Radiation-Hardness Testing of Electronic Devices
bremsstrahlung photons shall be equal to or greater than 2
E 925 Practice for the Periodic Calibration of Narrow Band-
MeV. For electron beams, the initial electron energy shall be
6
Pass Spectrophotometers
greater than 8 MeV.
E 958 Practice for Measuring Practical Spectral Bandwidth
NOTE 1—The lower energy limits given are appropriate for a cylindri- 6
of Ultraviolet-Visible Spectrophotometers
cal dosimeter ampoule of 12 mm diameter. Corrections for displacement
E 1026 Practice for Using the Fricke Reference Standard
effects and dose gradient across the ampoule may be required for electron
4
Dosimetry System
beams (2). The dichromate system may be used at lower energies by
2.2 ISO/ASTM Standards:
employing thinner (in the beam direction) dosimeter containers (see ICRU
51205 Practice for Use of a Ceric-Cerous Sulfate Dosimetry
Report 35).
4
System
1.4.4 The irradiation temperature of the dosimeter shall be
51261 Guide for Selection and Calibration of Dosimetry
above 0°C and should be below 80°C.
4
Systems for Radiation Processing
NOTE 2—The temperature coefficient of dosimeter response is known
51400 Practice for Characterization and Performance of a
only in the range of 5° to 50°C (see 10.1.8). Use outside this range is not 4
High-Dose Radiation Dosimetry Calibration Laboratory
recommended.
51707 Guide for Estimating Uncertainties in Dosimetry for
4
Radiation Processing
2.3 International Commission on Radiation Units and
1
This practice is under the jurisdiction of ASTM Committee E10 on Nuclear
7
Measurements (ICRU) Reports:
Technology and Applications and is the direct responsibility of Subcommittee
ICRU Report 14 Radiation Dosimetry: X-Rays and Gamma
E10.01 on Dosimetry for Radiation Processing, and is also under the jurisdiction of
ISO/TC 85/WG 3.
Current edition approved Jan. 22, 2002. Published March 15, 2002. Originally
e1 3
published as E 1401 – 91. Last previous ASTM edition E 1401 – 96 . ASTM Annual Book of ASTM Standards, Vol 15.02.
e1 4
E1401–96 was adopted by ISO in 1998 with the intermediate designation ISO Annual Book of ASTM Standards, Vol 12.02.
5
15561:1998(E). The present International Standard ISO/ASTM 51401:2002(E) is a
Annual Book of ASTM Standards, Vol 14.02.
6
revision of ISO 15561.
Annual Book of ASTM Standards, Vol 03.06.
2
7
The boldface numbers in parentheses refer to the bibliography at the end of this
Available from the Commission on Radiation Units and Measurements (ICRU),
practice.
7910 Woodmont Ave., Bethesda, MD 20814, U.S.A.
© ISO/ASTM International 2002 – All rights reserved
1

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ISO/ASTM 51401:2002(E)
Rays with Maximum Photon Energies Between 0.6 and 60 4.2 The dosimeter is a solution containing silver and dichro-
MeV mate ions in perchloric acid in an appropriate container such as
ICRU Report 34 The Dosimetry of Pulsed Radiation a flame-sealed glass ampoule. The solution indicates absorbed
ICRU Report 35 Radiation Dosimetry: Electrons With Ini- dose by a change (decrease) in optical absorbance at a specified
tial Energies Between 1 and 50 MeV wavelength(s) (3). A calibrated spectrophotometer is used to
ICRU Report 37 Stopping Powers for Electrons and measure the absorbance.
Positrons 4.3 Effect of Irradiation Temperature:
ICRU Report 60 Radiation Quantities and Units 4.3.1 The dosimeter response has a temperature dependence
during irradiation that is approximately equal to −0.2 % per
3. Terminology
degree Celsius between 25 and 50°C. At temperatures below
3.1 Definitions:
25°C, the dependence is smaller. The dosimeter response
3.1.1 absorbed dose (D)—quantity of ionizing radiation
between 5 and 50°C is shown in Table 1, where the response at
energy imparted per unit mass of a specified material. The SI
a given temperature is tabulated relative to the response at
unit of absorbed dose is the gray (Gy), where 1 gray is
25°C (4).
equivalent to the absorption of 1 joule per kilogram of the
4.3.2 The data in Table 1 may be fitted with an appropriate
specified material (1 Gy = 1 J/kg). The mathematical relation-
formula for convenience of interpolation as follows:
ship is the quotient of de¯ by dm, where de¯ is the mean
b2
R 5 b 1 b T (3)
incremental energy imparted by ionizing radiation to matter of T 0 1
incremental mass dm (see ICRU Report 60).
where:
de¯
R = dosimeter response at temperature T relative to that at
T
D 5 (1)
dm
25°C.
3.1.1.1 Discussion—The discontinued unit for absorbed
dose is the rad (1 rad = 100 erg/g = 0.01 Gy). Absorbed dose is The fitted data is shown in Fig. 1.
4.4 No effect of ambient light (even direct sunlight) has
sometimes referred to simply as dose.
3.1.2 calibration facility—combination of an ionizing radia- been observed on dichromate solutions in glass ampoules (5).
4.5 For calibration with photons, the dichromate dosimeter
tion source and its associated instrumentation that provides a
shall be irradiated under conditions that approximate electron
uniform and reproducible absorbed dose, or absorbed-dose rate
equilibrium.
traceable to national or international standards at a specified
4.6 The absorbed dose in other materials irradiated under
location and within a specific material, and that may be used to
equivalent conditions may be calculated. Procedures for mak-
derive the dosimetry system’s response function or calibration
ing such calculations are given in ASTM Practices E 666,
curve.
E 668 and ISO/ASTM Guide 51261.
3.1.3 dosimetry system—a system used for determining
absorbed dose, consisting of dosimeters, measurement instru-
NOTE 4—For a comprehensive discussion of various dosimetry meth-
ments, and their associated reference standards, and procedures
ods applicable to the radiation types and energies discussed in this
for the system’s use.
practice, see ICRU Reports 14, 34, 35, and 37.
3.1.4 measurement quality assurance plan—a documented
4.7 The dosimeter response is dependent on the type and
program for the measurement process that ensures on a
energy of the radiation employed. For example, the response in
continuing basis that the overall uncertainty meets the require-
high energy (10 MeV) electron beams is reported to be
ments of the specific application. This plan requires traceability
approximately 3 % lower than the response in cobalt-60
to, and consistency with, nationally or internationally recog-
radiation (2). The dosimeter shall be calibrated in a radiation
nized standards.
field of the same type and energy as that in which it is to be
3.1.5 net absorbance, (DA)—change in measured optical
used.
absorbance at a selected wavelength determined as the absolute
difference between the pre-irradiation absorbance, A , and the
0 5. Interferences
post-irradiation absorbance, A, as follows:
5.1 The dichromate dosimetric solution response is sensitive
DA 5 ?A 2 A ? (2)
0
to impurities, particularly organic impurities. Even in trace
quantities, impurities can cause a detectable change in the
3.1.6 reference–standard dosimeter—a dosimeter of high
observed response (5). For high accuracy results, organic
metrological quality, used as a standard to provide measure-
ments traceable to and consistent with measurements made
using primary–standard dosimeters.
TABLE 1 Effect of Irradiation Temperature on Dosimeter
Response
NOTE 3—For other terms, see ASTM Terminology E 170.
Temperature, °C Response Temperature, °C Response
4. Significance and Use
5 1.020 30 0.992
4.1 The dichromate system provides a reliable means for 10 1.017 35 0.983
15 1.013 40 0.972
measuring absorbed dose in water. It is based on a process of
20 1.007 45 0.960
reduction of dichromate ions to chromic ions in acidic aqueous
25 1.000 50 0.948
solution by ionizing radiation.
© ISO/ASTM International 2002 – All rights reserved
2

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ISO/ASTM 51401:2002(E)
distilled water (see ASTM Practice C 912). Dry thoroughly and
store in a dust-free environment (see ASTM Practice E 1026).
7. Reagents
7.1 Analytical reagent grade (or better) chemicals shall be
used in this practice for preparing all solutions.
7.2 Use of double-distilled water from coupled all-glass and
silica stills is recommended. Water purity is very important
since it is the major constituent of the dosimetric solutions, and
therefore may be the prime source of contamination. Use of
deionized water is not recommended.
NOTE 6—Double-distilled water distilled from an alkaline permangan-
ate (KMnO ) solution (2 g KMnO plus 5 g sodium hydroxide (NaOH)
4 4
3
pellets in 2 dm of distilled water) has been found to be adequate for
routine preparation of the dichromate dosimetric solution. High purity
water is commercially available from some suppliers. Such water labelled
HPLC (high pressure liquid chromatography) grade is usually sufficiently
FIG. 1 Relative Response of Dichromate Dosimeter as a Function
free of organic impurities to be used in this practice.
of Irradiation Temperature. A Fit of the Data Using Eq 3 Yields Fit
−5
Parameters as Follows: b = 1.021; b = −6.259 3 10 ; b = 1.806.
0 1 2
8. Preparation of Dosimeters
8.1 The recommended concentrations for the dichromate
materials shall not be used for any component in contact with
dosimeter to measure absorbed doses from about 2 to 10 kGy
−3
the solution. The effect of trace impurities may be minimized (hereafter called the low-range dosimeter) are 0.5 3 10 mol
−3 −3
by pre-irradiation of the bulk dichromate solution (see Ref (5)
dm silver dichromate (Ag Cr O ) in 0.1 mol dm aqueous
2 2 7
and 8.2).
perchloric acid (6). For measurement of absorbed doses from
5.2 Undesirable chemical changes in the dosimetric solution
about 5 to 50 kGy (using the dosimeter hereafter called the
can occur if care is not taken during flame-sealing of the
high-range dosimeter), the recommended concentrations are
−3 −3 −3
ampoules (see 8.4).
0.5 3 10 mol dm silver dichromate and 2.0 3 10 mol
−3 −3
dm potassium dichromate (K Cr O ) in 0.1 mol dm aque-
2 2 7
6. Apparatus
ous perchloric acid (5). Air saturate both solutions before use.
Silver dichromate dissolves slowly and normally requires at
6.1 High-Precision Spectrophotometer—For the analysis of
least 18 h to dissolve completely. For the high range dosimeter,
the dosimetric solution, use a high-precision spectrophotom-
it is preferable to dissolve the
...