ISO/ASTM 51538:2002

Practice for use of the ethanol-chlorobenzene dosimetry system

ISO/ASTM 51538 covers the preparation, handling, testing and procedure for using the ethanol-chlorobenzene dosimetry system to measure absorbed doses in materials irradiated by photons and electrons in terms of absorbed dose in water. The system consists of a dosimeter and appropriate analytical instrumentation. This practice describes the titration analysis as a standard readout procedure for the ECB dosimeter and applies only to gamma rays, X rays and high-energy electrons. This practice applies provided the following are satis-fied: the absorbed dose range is from 10 Gy to 2 MGy; the absorbed dose rate does not exceed 106 Gy s -1; 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 equal to or greater than 4 MeV. the irradiation temperature of the dosimeter is within the range from - 40 °C to 80°C; the effects of size and shape of the irradiation vessel on the response of the dosimeter can adequately be taken into account by performing the appropriate calculations using cavity theory.

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

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• Status: Withdrawn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: 07-Jul-2009

Relations

• Revised: ISO/ASTM 51538:2009 - Practice for use of the ethanol-chlorobenzene dosimetry system
• Effective Date: 15-Apr-2008
• Revises: ISO 15563:1998 - Practice for use of the ethanol-chlorobenzene dosimetry system
• Effective Date: 15-Apr-2008

Standards Content (Sample)

INTERNATIONAL ISO/ASTM
STANDARD 51538
First edition
2002-03-15
Practice for use of the ethanol-
chlorobenzene dosimetry system
Pratique de l’utilisation d’un système dosimétrique à l’éthanol
chlorobenzène
Reference number
ISO/ASTM 51538:2002(E)
© ISO/ASTM International 2002

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ISO/ASTM 51538:2002(E)
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ii © ISO/ASTM International 2002 – All rights reserved

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ISO/ASTM 51538:2002(E)
Contents Page
1 Scope . 1
2 Referenced documents . 1
3 Terminology . 2
4 Significance and use . 3
5 Interferences . 3
6 Apparatus . 3
7 Reagents . 3
8 Preparation of dosimeters . 4
9 Calibration of the mercuric nitrate solution . 4
10 Calibration of the dosimetry system . 4
11 Measurement . 5
12 Analysis . 5
13 Minimum documentation requirements . 5
14 Measurement uncertainty . 6
15 Keywords . 6
Annexes . 6
Bibliography . 9
Table 1 Typical ECB solution formulations . 4
Table A3.1 Characteristics of some applicable methods . 8
Table A3.2 Some suppliers of readout instruments suitable for use with ethanol-chlorobenzene
(ECB) dosimetry . 9
Table A3.3 Some suppliers of ethanol-chlorobenzene (ECB) dosimeters . 9
© ISO/ASTM International 2002 – All rights reserved iii

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ISO/ASTM 51538:2002(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 51538 was developed by ASTM Committee E10, Nuclear Technology and
Applications, through Subcommittee E10.01, and by Technical Committee ISO/TC 85, Nuclear Energy.
Annexes A1, A2 and A3 of this International Standard are for information only.
iv © ISO/ASTM International 2002 – All rights reserved

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ISO/ASTM 51538:2002(E)
Standard Practice for
1
Use of the Ethanol-Chlorobenzene Dosimetry System
This standard is issued under the fixed designation ISO/ASTM 51538; the number immediately following the designation indicates the
year of original adoption or, in the case of revision, the year of last revision.
NOTE 2—The temperature dependence of dosimeter response is known
1. Scope
only in this range. For use outside this range, the dosimetry system should
1.1 This practice covers the preparation, handling, testing,
be calibrated for the required range of irradiation temperatures.
and procedure for using the ethanol-chlorobenzene dosimetry
1.4.5 The effects of size and shape of the irradiation vessel
system to measure absorbed dose in materials irradiated by
on the response of the dosimeter can adequately be taken into
photons and electrons in terms of absorbed dose in water. The
account by performing the appropriate calculations using
system consists of a dosimeter and appropriate analytical
cavity theory (5).
instrumentation. For simplicity, the system will be referred to
1.5 This standard does not purport to address all of the
as the ECB system. It is classified as a reference–standard
safety concerns, if any, associated with its use. It is the
dosimeter and is also used as a routine dosimetry system (see
responsibility of the user of this standard to establish appro-
ISO/ASTM Guide 51261).
priate safety and health practices and determine the applica-
1.2 This practice describes the titration analysis as a stan-
bility of regulatory limitations prior to use.
dard readout procedure for the ECB dosimeter. Other appli-
cable readout methods (spectrophotometric, oscillometric) are
2. Referenced Documents
described in Annex A1 and Annex A2.
2.1 ASTM Standards:
1.3 This practice applies only to gamma rays, X rays, and
C 912 Practice for Designing a Process for Cleaning Tech-
high-energy electrons.
3
nical Glasses
1.4 This practice applies provided the following are satis-
D 941 Test Method for Density and Relative Density (Spe-
fied:
cific Gravity) of Liquids by Lipkin Bicapillary Pycnom-
1.4.1 The absorbed dose range shall be from 10 Gy to 2
4
eter
2
MGy (1).
5
6 −1 D 1193 Specification for Reagent Water
1.4.2 The absorbed dose rate does not exceed 10 Gy s (2).
E 170 Terminology Relating to Radiation Measurements
1.4.3 For radionuclide gamma-ray sources, the initial pho-
6
and Dosimetry
ton energy shall be greater than 0.6 MeV. For bremsstrahlung
E 177 Practice for Use of the Terms Precision and Bias in
photons, the initial energy of the electrons used to produce the
7
ASTM Test Methods
bremsstrahlung photons shall be equal to or greater than 2
7
E 178 Practice for Dealing with Outlying Observations
MeV. For electron beams, the initial electron energy shall be
E 275 Practice for Describing and Measuring Performance
equal to or greater than 4 MeV (3) (see ICRU Reports 34 and
of Ultraviolet, Visible, and Near Infrared Spectrophotom-
35).
8
eters
7
NOTE 1—The lower limits of electromagnetic radiation energy given
E 456 Terminology Relating to Quality and Statistics
are appropriate for a cylindrical dosimeter ampoule of 12-mm diameter.
E 666 Practice for Calculating Absorbed Dose from Gamma
Corrections for dose gradients across an ampoule of that diameter or less
6
or X-Radiation
are not required. The ECB system may be used at energies of incident
E 668 Practice for Application of Thermoluminescence Do-
electrons lower than 4 MeV by employing thinner (in the beam direction)
simetry (TLD) Systems for Determining Absorbed Dose in
dosimeter containers (see ICRU Report 35). The ECB system may also be
6
used at X-ray energies as low as 120 kVp (4). In this range of photon Radiation-Hardness Testing of Electronic Devices
energies the effect caused by the wall is considerable.
E 925 Practice for the Periodic Calibration of Narrow Band-
8
Pass Spectrophotometers
1.4.4 The irradiation temperature of the dosimeter should be
E 958 Practice for Measuring Practical Spectral Bandwidth
within the range from −40°C to 80°C.
8
of Ultraviolet-Visible Spectrophotometers
E 1026 Practice for Using the Fricke Reference Standard
6
Dosimetry System
1
This practice is under the jurisdiction of ASTM Committee E10 on Nuclear
2.2 ISO/ASTM Standards:
Technology and Applications and is the direct responsibility of Subcommittee
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 1538-93. Last previous ASTM edition E 1538–99 . ASTM E
Annual Book of ASTM Standards, Vol 15.02.
4
1538–93 was adopted by ISO in 1998 with the intermediate designation ISO
Annual Book of ASTM Standards, Vol 15.01.
5
15563:1998(E). The present International Standard ISO/ASTM 51538:2002(E) is a
Annual Book of ASTM Standards, Vol 11.01.
6
revision of ISO 15563.
Annual Book of ASTM Standards, Vol 12.02.
2
7
The boldface numbers in parentheses refer to the bibliography at the end of this
Annual Book of ASTM Standards, Vol 14.02.
8
practice. Annual Book of ASTM Standards, Vol 03.06.
© ISO/ASTM International 2002 – All rights reserved
1

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ISO/ASTM 51538:2002(E)
51204 Practice for Dosimetry in Gamma Irradiation Facili- charged particle equilibrium, the absorbed dose, D, may be
6
ties for Food Processing expressed as:
51205 Practice for Use of a Ceric-Cerous Sulfate Dosimetry
μ
en
6
D5F · E · (2)
System
r
51261 Guide for Selection and Calibration of Dosimetry
6
where:
Systems for Radiation Processing
2
F = particle fluence (particles/m ),
51400 Practice for Characterization and Performance of a
E = energy of the ionizing radiation (J), and
High-Dose Gamma-Radiation Dosimetry Calibration
2
6 μ /r = mass energy absorption coefficient (m /kg). If
en
Laboratory
6 bremsstrahlung production within the specified
51401 Practice for Use of a Dichromate Dosimetry System
material is negligible, the mass energy absorption
51431 Practice for Dosimetry in Electron and Bremsstrahl-
6 coefficient (μ /r) is equal to the mass energy
en
ung Irradiation Facilities for Food Processing
transfer coefficient (μ /r), and absorbed dose is
tr
51540 Practice for Use of a Radiochromic Liquid Dosim-
6 equal to kerma if, in addition, charged particle
etry System
equilibrium exists.
51649 Practice for Dosimetry in an Electron Beam Facility
3.1.2 calibration—the process whereby the response of a
for Radiation Processing at Energies between 300 keV and
6 measuring system or measuring instrument is characterized
25 MeV
through comparison with an appropriate standard that is
51707 Guide for Estimating Uncertainties in Dosimetry for
6 traceable to and consistent with a nationally or internationally
Radiation Processing
9 recognized standard.
2.3 ISO Standard:
3.1.3 calibration curve—graphical representation of the
ISO 11137 Sterilization of Health Care Products—
dosimetry system’s response function.
Requirements for Validation and Routine Control—
3.1.4 calibration facility—combination of an ionizing radia-
Radiation Sterilization
tion source and its associated instrumentation that provides a
2.4 International Commission on Radiation Units and
10
uniform and reproducible absorbed dose, or absorbed-dose rate
Measurements (ICRU) Reports:
traceable to national or international standards at a specified
ICRU Report 14 Radiation Dosimetry: X-Rays and Gamma
location and within a specific material, and that may be used to
Rays with Maximum Photon Energies Between 0.6 and 60
derive the dosimetry system’s response function or calibration
MeV
curve.
ICRU Report 17 Radiation Dosimetry: X-Rays Generated
3.1.5 conductivity—the conductivity of a solution is usually
at Potentials of 5 to 150 kV
defined in terms of specific conductivity (k), which is given by
ICRU Report 34 The Dosimetry of Pulsed Radiation
2
the conductivity of a solution between electrodes of 1 cm
ICRU Report 35 Radiation Dosimetry: Electrons with
surface area, placed 1 cm from each other.
Initial Energies Between 1 and 50 MeV
3.1.6 conductometry—analytical method based on the mea-
ICRU Report 37 Stopping Powers for Electrons and
surement of conductivity of solutions due to the relationship
Positrons
between concentration and conductivity of electrolytes. The
ICRU Report 44 Tissue Substitutes in Radiation Dosimetry
conductivity of a solution depends on the concentration of free
and Measurements
ions in the solution.
ICRU Report 60 Radiation Quantities and Units
3.1.7 dosimetry system—a system used for determining
3. Terminology absorbed dose, consisting of dosimeters, measurement instru-
ments and their associated reference standards, and procedures
3.1 Definitions:
for the system’s use.
3.1.1 absorbed dose, D—quantity of ionizing radiation
3.1.8 measurement quality assurance plan— a documented
energy imparted per unit mass of a specified material. The SI
program for the measurement process that ensures on a
unit of absorbed dose is the gray (Gy), where 1 gray is
continuing basis that the overall uncertainty meets the require-
equivalent to the absorption of 1 joule per kilogram of the
ments of the specific application; this plan requires traceability
specified material (1 Gy = 1 J/kg). The mathematical relation-
to, and consistency with, nationally or internationally recog-
ship is the quotient of de¯ by dm, where de¯ is the mean
nized standards.
incremental energy imparted by ionizing radiation to matter of
3.1.9 measurement traceability—the ability to demonstrate
incremental mass dm (see ICRU 60).
by means of an unbroken chain of comparisons that a mea-
D 5 de¯ /dm (1)
surement is in agreement within acceptable limits of uncer-
3.1.1.1 Discussion—Absorbed dose is sometimes referred
tainty with comparable nationally or internationally recognized
to simply as dose. For a photon source under conditions of
standards.
3.1.10 molar linear absorption coeffıcient e —a constant
m
relating the spectrophotometric absorbance, A , of an optically
l
9
Available from International Organization for Standardization, 1 Rue de
absorbing molecular species, x, at a given wavelength, l, per
Varembé, Case Postale 56, CH-1211 Geneva 20, Switzerland.
10
unit pathlength, d, to the molar concentration, [x], of that
Available from the Commission on Radiation Units and Measurements, 7910
Woodmont Ave., Suite 800, Bethesda, MD 20814, USA. species in its host substance:
© ISO/ASTM International 2002 – All rights reserved
2

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ISO/ASTM 51538:2002(E)
A 1
chemical responses applicable under the circumstances be
l
e 5 3 (3)
m
d
@x#
established in advance.
2 −1
(SI unit: m · mol )
5. Interferences
3.1.10.1 Discussion—The measurement is sometimes ex-
−1 −1
pressed in units of L mol cm ).
5.1 The ECB dosimetric solution response is not particu-
3.1.11 oscillometry—an electroanalytical method of con-
larly sensitive to impurities which occur in commercially
ductivity measurements, when high-frequency (1 to 600 MHz)
available components, chlorobenzene and ethanol of the ana-
alternating current is applied to measure or follow changes in
lytical reagent (AR) grade purity or equivalent (pro analysi,
the composition of chemical systems. p.a., and puriss.). For high-accuracy results, organic materials
3.1.12 radiation chemical yield G(x)— the quotient of n(x)
of technical grade purity (or purum) can be purified by
by e¯ where n(x) is the mean amount of a specified entity, x, distillation.
produced, destroyed, or changed by the mean energy, e¯
5.2 Care should be exercised in filling ampoules to avoid
imparted to the matter.
depositing solution in the ampoule neck. Subsequent heating
during sealing of the ampoule may cause an undesirable
G x! 5 n x! / e¯! (4)
~ ~ ~
chemical change in the dosimetric solution remaining inside
−1
(SI unit: mol · J )
the ampoule’s neck. Test tubes with ground-glass stoppers are
3.1.13 reference–standard dosimeter—a dosimeter of high
therefore preferred to sealed ampoules for measuring doses
metrological quality, used as a standard to provide measure-
below 100 Gy. For the same reason, care should be given to
ments traceable to, and consistent with measurements made
avoid heating the body of the ampoule during sealing.
using primary standard dosimeters.
5.3 The dosimetric solution is somewhat sensitive to ultra-
3.1.14 routine dosimeter—dosimeter calibrated against a
violet light and should be kept in the dark for long-term
primary-, reference-, or transfer-standard dosimeter and used
storage. No special precautions are required during routine
for routine absorbed-dose measurement.
handling under normal laboratory lighting conditions, but
3.1.15 traceability—the ability to show that a measurement
strong ultraviolet (UV) sources such as sunlight should be
is consistent with appropriate national standards through an
avoided (15).
unbroken chain of comparisons.
3.2 For other terms, see ASTM Terminology E 170.
6. Apparatus
4. Significance and Use
6.1 This practice describes mercurimetric titration of radi-
−
4.1 The ECB dosimetry system provides a reliable means of
olytically formed Cl ions as a standard readout procedure.
measuring absorbed dose in materials. It is based on a process
6.2 For the analysis of the dosimetric solution, use a
of radiolytic formation of hydrochloric acid (HCl) in aqueous
precision burette capable of measuring volumes with 0.01–mL
ethanolic solutions of chlorobenzene by ionizing radiation (6,
resolution. If necessary, check the original calibration of
7).
volumetric glassware and, if necessary, recalibrate to attain
4.2 The dosimeters are partly deoxygenated solutions of
0.1 % relative error. Control the temperature of all solutions
chlorobenzene (CB) in 96 volume % ethanol in an appropriate
during handling at 20°C.
container, such as a flame-sealed glass ampoule. The solutions
6.3 Use borosilicate glass or equivalent chemically resistant
indicate absorbed dose by the amount of HCl formed. A
glass to store the reagents, the prepared dosimeter solution, and
number of analytical methods are available for measuring the
to perform the titration. Clean all apparatus thoroughly before
amount of HCl in ethanol (8).
use (see Practice C 912).
4.3 The concentration of chlorobenzene in the solution can
6.4 Use a sealed glass ampoule or other appropriate glass
be varied so as to simulate a number of materials in terms of
container to hold the dosimetric solution during irradiation. For
the photon mass energy-absorption coefficients (μ /r) for X-
en
photons, surround the container with material of thickness
and gamma rays, and electron mass collision stopping powers
sufficient to produce approximate electron equilibrium condi-
−2
(1/r)( dE/dx), over a broad spectral energy range from 10 to
tions during calibration irradiations. For measurement of ab-
100 MeV (9-12).
sorbed dose in water, use materials that have radiation-
4.4 The absorbed dose that is measured is the dose absorbed
absorption properties essentially equivalent to water, for
in the dosimeter. Absorbed dose in other materials irradiated
example, polystyrene and polyethylene. The appropriate thick-
under equivalent conditions may be calculated. Procedures for
ness of such material depends on the energy of the photon
making such calculations are given in ASTM Practices E 666
radiation (see ASTM Practices E 666 and E 668).
and E 668 and ISO/ASTM Guide 51261.
NOTE 4—The dosimetric ampoule commonly used has a capacity of
NOTE 3—For a comprehensive discussion of various dosimetry meth-
about 5 mL. Quick-break, glass ampoules or “Type 1 glass” colorbreak
ods applicable to the radiation types and energies discussed in this
ampoules or equivalent containers, may be used. Commercially available
practice, see ICRU Reports 14, 17, 34, 35, and 37.
pharmaceutical ampoules have been found to give reproducible results
without requiring additional cleaning.
4.5 The ECB dosimetry system may be used with other
radiation types, such as neutrons (13), and protons (14).
7. Reagents
Meaningful dosimetry of any radiation types and energies
7.1 Analytical reagent grade chemicals shall be used in this
novel to the system’s use requires that the respective radiation
© ISO/ASTM International 2002 – All rights reserved
3

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ISO/ASTM 51538:2002(E)
11
practice for preparing all solutions. chloride ions formed by irradiation. Free chloride is precipi-
7.2 Use of triply distilled water from coupled all-glass stills tated with mercuric ions as insoluble HgCl , where-upon the
2
2+
is recommended. Type II reagent water as specified in ASTM excess of Hg ions gives a violet-red coloration with the
Specification D 1193 is also considered to be of sufficient indicator diphenylcarbazone in acid medium (17).
−4 −3
quality for use in preparing solutions and 96 volume % ethanol. 9.2 Prepare approximately 5 3 10 mol·dm Hg(NO )
3 2
in acidic aqueous ethanol. First dissolve an appropriate amount
NOTE 5—High-purity water is commercially available from some
of Hg(NO ) in water acidified with sufficient HNO to attain
3 2 3
suppliers. Such water, labelled HPLC (high-pressure liquid chromatogra-
the concentration of the acid in the final solution, 0.05 mol ·
phy) grade, is usually sufficiently free of impurities to be used in this
−3
dm .
practice.
NOTE 8—Caution: Mercuric (II) nitrate is highly toxic. Acute exposure
8. Preparation of Dosimeters
of skin and mucous membranes produces violent corrosive effects.
8.1 Dosimeter solutions may contain any concentration of
Chronic exposure causes many pathological changes. Appropriate precau-
CB. For practical reasons, only several characteristic formula-
tions should be exercised in handling it. Hazards of mercury poisoning can
tions have been thoroughly characterized. Table 1 lists these be avoided by using some of the alternative readout methods described in
Annex A1 and Annex A2.
typical formulations in terms of CB concentrations and radia-
tion chemical yields pertaining to these concentrations.
9.2.1 Prepare standard solutions of NaCl in water. Make
several concentrations to enable cross-checking. Suitable con-
−3 −2 −2
TABLE 1 Typical ECB Solution Formulations
centrations are 5 3 10 , 1.0 3 10 , 1.5 3 10 , and 2.0 3
B −2 −3
Radiation Chemical Yields
10 mol·dm . If kept properly in ground-glass stoppered
−1)
(μmol· J
bottles, these solutions are stable for years. Avoid contamina-
Concentration Density at 20°C Ratio of
60
−3 A
Co 4to10MeV
of CB, vol % kg·m Coefficients tion of the standard solutions by using for daily work small
Gamma Electrons (3)
portions of these solutions kept in small ground-glass stop-
Rays (16)
pered flasks. Replenish standard solutions in the small flasks as
C
4 819 0.989 0.42
necessary.
10 839 0.995 0.52
−3
20 869 1.006 0.59
9.2.2 Prepare 0.2 mol · dm HNO in ethanol and 1 %
3
D
24 880 1.011 0.60 0.57
ethanolic solutions of diphenylcarbazone (DPC).
40 925 1.027 0.63
9.3 Distribute technical grade ethanol to beakers for titra-
A
The ratio of the mass energy-absorption coefficients for water and the
60 tion, 10 mL into each. Pipet standard NaCl solution quantita-
dosimeter solution at Co gamma ray energy:
~μ /r! tively to beakers with ethanol. Add 1 mL of 0.2 M HNO and
en w
3
f 5
~μ /r!
en D 7 drops of 1 % DPC and shake. Titrate with Hg(NO ) solution
3 2
B
Radiation chemical yields of HCl in the dose range from 100 Gy to 100 kGy.
C from the burette. The solution in the beaker which is initially
Upper dose range 20 kGy.
D
Lower dose range 1 kGy. This formulation also contained 0.04 volume % yellow-orange turns to reddish-violet at the end point.
acetone and 0.04 volume % benzene.
9.4 Construct or calculate the best straight line through the
points: (consumption of Hg(NO ) ) versus (milliequivalents of
3 2
8.2 Prepare 96 volume % aqueous ethanol first by adding
NaCl). The small positive intercept represents the blank;
absolute ethanol into a volumetric flask containing the appro-
inverse slope gives concentration of Hg(NO ) solution.
3 2
priate amount of water. Use this aqueous ethanol for making
NOTE 9—Volumes of the standard NaCl solutions should be such that
the dosimeter solutions of the desired concentrations by adding
the consumption of the titrant solution on calibration are similar to the
it into volumetric flasks containing appropriate amounts of CB.
consumptions when analyzing irradiated dosimetric solutions. Take two
Store the dosimeter solution in the dark.
different volumes of each standard solution to enable cross-checking. The
concentration of mercuric nitrate solution should be calibrated daily.
NOTE 6—Caution: Chlorobenzene is toxic and a skin irritant. Appro-
priate precautions should be exercised in handling it.
10. Calibration of the Dosimetry System
8.3 Fill the dosimeter ampoules with the dosimeter solution.
10.1 Prior to use, the dosimetry system shall be calibrated in
Bubble the solution in the ampoule with nitrogen for about 1
accordance with the user’s documented procedure that speci-
min at about 1 bubble per second through a 1-mm capillary.
fies details of the calibration process and quality assurance
Flame-seal immediately after bubbling. Exercise care to avoid
requirements. This calibration procedure shall be repeated at
depositing solution in the ampoule neck. Store dosimeters in
regular intervals to ensure that the accuracy of the absorbed
the dark.
dose measurement is maintained within required limits. De-
tailed calibration procedures are provided in ISO/ASTM Guide
NOTE 7—Nitrogen may be saturated by passing it through the ECB
solution of the same composition before bubbling the dosimeter ampoules 51261.
to avoid changing the composition of dosimeter solution by evaporation.
10.2 Calibration Irradiation of Dosimeters—Irradiation is a
critical component of the calibration of the dosimetry system.
9. Calibration of the Mercuric Nitrate Solution
Calibration irradiations shall be performed by irradiating the
9.1 The measurement procedure is based on the titration of
dosimeters using a calibration facility that provides an ab-
sorbed dose or an absorbed-dose rate having measurement
11 traceability to nationally or internationally recognized stan-
Reagent specifications are available from the American Chemical Society,
1115 16th Street, NW, Washington, DC 20036, USA. dards.
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4

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ISO/ASTM 51538:2002(E)
of the solution, or som
...