ASTM E1026-95
(Practice)Standard Practice for Using the Fricke Reference Standard Dosimetry System
Standard Practice for Using the Fricke Reference Standard Dosimetry System
SCOPE
1.1 This practice covers the preparation, testing and procedure for using the acidic aqueous ferrous ammonium sulfate solution 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 Fricke system. It is classified as a reference standard dosimeter (see Guide E1261).
1.2 The practice describes the spectrophotometric analysis procedures for the Fricke dosimeter.
1.3 This practice applies only to [gamma] 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 from 40 to 400 Gy (1).
1.4.2 The absorbed dose rate shall not exceed 106 Gy[dot]s -1 (2).
1.4.3 For radioisotope 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 (see ICRU Reports 34 and 35). Note 1-The lower energy limits given 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. The Fricke 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 should be within the range of 10 to 60°C.
1.5 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.
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Standards Content (Sample)
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
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Designation: E 1026 – 95
Standard Practice for
Using the Fricke Reference Standard Dosimetry System
This standard is issued under the fixed designation E 1026; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
1.1 This practice covers the preparation, testing and proce- 2.1 ASTM Standards:
dure for using the acidic aqueous ferrous ammonium sulfate C 912 Practice for Designing a Process for Cleaning Tech-
solution dosimetry system to measure absorbed dose in water nical Glasses
when exposed to ionizing radiation. The system consists of a D 1193 Specification for Reagent Water
dosimeter and appropriate analytical instrumentation. For sim- E 170 Terminology Relating to Radiation Measurements
plicity, the system will be referred to as the Fricke system. It is and Dosimetry
classified as a reference standard dosimeter (see Guide E 178 Practice for Dealing with Outlying Observations
E 1261). E 275 Practice for Describing and Measuring Performance
1.2 The practice describes the spectrophotometric analysis of Ultraviolet, Visible, and Near Infrared Spectrophotom-
procedures for the Fricke dosimeter. eters
1.3 This practice applies only to g rays, x rays, and E 666 Practice for Calculating Absorbed Dose from Gamma
high-energy electrons. or X-Radiation
1.4 This practice applies provided the following are satis- E 668 Practice for Application of Thermoluminescence-
fied: Dosimetry (TLD) Systems for Determining Absorbed Dose
1.4.1 The absorbed dose range shall be from 40 to 400 Gy in Radiation-Hardness Testing of Electronic Devices
(1). E 925 Practice for the Periodic Calibration of Narrow Band-
6 −1 8
1.4.2 The absorbed dose rate shall not exceed 10 Gy·s (2). Pass Spectrophotometers
1.4.3 For radioisotope gamma-ray sources, the initial pho- E 958 Practice for Measuring Practical Spectral Bandwidth
ton energy shall be greater than 0.6 MeV. For bremsstrahlung of UltraViolet-Visible Spectrophotometers
photons, the initial energy of the electrons used to produce the E 1205 Method for Using the Ceric-Cerous Sulfate Dosim-
bremsstrahlung photons shall be equal to or greater than 2 etry System
MeV. For electron beams, the initial electron energy shall be E 1261 Guide for Selection and Application of Dosimetry
greater than 8 MeV (see ICRU Reports 34 and 35). Systems for Radiation Processing of Food
2.2 International Commission on Radiation Units and
NOTE 1—The lower energy limits given are appropriate for a cylindri-
Measurements (ICRU) Reports:
cal dosimeter ampoule of 12 mm diameter. Corrections for dose gradients
ICRU Report 14 Radiation Dosimetry: X-Rays and Gamma
across an ampoule of that diameter or less are not required. The Fricke
system may be used at lower energies by employing thinner (in the beam Rays with Maximum Photon Energies between 0.6 and 60
direction) dosimeter containers (see ICRU Report 35).
MeV
ICRU Report 33 Radiation Quantities and Units
1.4.4 The irradiation temperature of the dosimeter should be
ICRU Report 34 The Dosimetry of Pulsed Radiation
within the range of 10 to 60°C.
ICRU Report 35 Radiation Dosimetry: Electrons with Ini-
1.5 This standard does not purport to address all of the
tial Energies Between 1 and 50 MeV
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
3. Terminology
priate safety and health practices and determine the applica-
3.1 absorbed dose, D—the quotient of de by dm, where de
bility of regulatory limitations prior to use.
Annual Book of ASTM Standards, Vol 15.02.
Annual Book of ASTM Standards, Vol 11.01.
1 5
This practice is under the jurisdiction of ASTM Committee E10 on Nuclear Annual Book of ASTM Standards, Vol 12.02.
Technology and Applications and is the direct responsibility of Subcommittee Annual Book of ASTM Standards, Vol 14.02.
E10.01 on Dosimetry for Radiation Processing. Annual Book of ASTM Standards, Vol 03.05.
Current edition approved April 15, 1995. Published June 1995. Originally Annual Book of ASTM Standards, Vol 14.01.
published as E 1026 – 84. Last previous edition E 1026 – 92. Annual Book of ASTM Standards, Vol 03.06.
2 10
The boldface numbers that appear in parentheses refer to a list of references at Available from the International Commission on Radiation Units and Mea-
the end of this practice. surements (ICRU), 7910 Woodmont Ave., Suite 800, Bethesda, MD 20814.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
E 1026
is the mean energy imparted by ionizing radiation to matter of of oxidation of ferrous ions to ferric ions in acidic aqueous
mass dm (see ICRU Report 33). solution by ionizing radiation (3). In situations not requiring
traceability to national standards, this system can be used for
D 5 de/dm
absolute determination of absorbed dose, as the radiation
The special name of the unit for absorbed dose is the gray
chemical yield of ferric ions is well known.
(Gy).
4.1.1 Fricke dosimetry cannot be used in situations where
1Gy 5 1 J·kg traceability to national standards of absorbed dose is required
unless the dosimetry system is calibrated in a calibration
3.1.1 Discussion—Formerly, the special unit for absorbed
facility. Irradiation of Fricke dosimeters in a calibration facility
dose was the rad.
is required in order to provide a means of verifying the
22 21 22
1 rad 5 10 J·kg 5 10 Gy
expected response of the dosimetry system.
4.2 The dosimeter is an air-saturated solution of ferrous
3.2 calibration facility—combination of an ionizing radia-
tion source and its associated instrumentation that provides ammonium sulfate that indicates absorbed dose by a change
(increase) in absorbance at a specified wavelength. A
traceable, uniform, and reproducible absorbed dose rates at
specific locations and in a specific material. It may be used to temperature-controlled calibrated spectrophotometer is used to
measure the absorbance.
calibrate the response of routine or other types of dosimeters as
a function of absorbed dose. 4.3 For calibration with photons, the Fricke dosimeter shall
3.3 measurement quality assurance plan—a documented be irradiated under conditions that approximate electron equi-
program for the measurement process that quantifies the total librium.
uncertainty of the measurements (both random and systematic 4.4 The absorbed dose in other materials irradiated under
equivalent conditions may be calculated. Procedures for mak-
error components). This plan shall demonstrate traceability to
national standards, and shall show that the total uncertainty ing such calculations are given in Practices E 666 and E 668
and Guide E 1261.
meets the requirements of the specific application.
3.4 molar linear absorption coeffıcient, e—quotient given 4.5 There are two factors associated with use of the Fricke
system at energies below those specified in 1.4.3:
by the relation from Beer’s law as follows:
4.5.1 The radiation chemical yield changes at low photon
e5 A/~M·d!
energies (4), and
where: 4.5.2 Dose gradients across the dosimeter with a dimension
A = absorbance at a specified wavelength,
in the beam direction exceeding 12 mm require corrections in
M = molar concentration of the ion of interest, and
dosimeter response at energies below 8 MeV for electrons (see
d = optical pathlength within the solution measured by the
ICRU Report 35).
spectrophotometer (see ICRU Report 35). Units:
2 −1
5. Interferences
m mol
3.4.1 Discussion—This quantity is often referred to in the
5.1 The Fricke dosimetric solution response is extremely
literature as the molar extinction coeffıcient. sensitive to impurities, particularly organic impurities. Even in
3.5 net absorbance, DA—the difference between the optical
trace quantities, impurities can cause a detectable change in the
absorbance of an unirradiated dosimetric solution, A , and the observed response. For high accuracy results, organic materials
o
optical absorbance of an irradiated dosimetric solution, A :
shall not be used for any component in contact with the
i
solution.
DA 5 A 2 A
i o
5.2 Traces of metal ions in the dosimetric or reference
3.6 radiation chemical yield, G(x)—the quotient of n(x) by
solutions can also cause problems. Therefore, do not use metal
e where n(x) is the mean amount of substance of a specified
in any component in contact with the solutions.
entity, x, produced, destroyed or changed by the mean energy
5.3 Exercise care in filling ampoules to avoid depositing
imparted, e, to the matter (see ICRU Report 33).
solution in the ampoule neck. Subsequent heating during
G~x! 5 n~x!/e
sealing of the ampoule may cause undesirable chemical change
−1
in the dosimetric solution remaining inside the ampoule’s neck.
Unit: mol·J .
For the same reason, exercise care to avoid heating the body of
3.6.1 Discussion—This quantity is often referred to as G
−1
the ampoule during sealing.
value. The former special unit was (100 eV) .
5.4 Thermal oxidation (as indicated by an increase in
3.7 reference standard dosimetry system—combination of a
absorbance), in the absence of radiation, is a function of
dosimeter and appropriate analytical instrumentation of high
temperature. At normal laboratory temperatures (about 20 to
metrological quality that is traceable to national standards.
25°C), this effect may cause a problem if there is a long period
3.8 traceability—the ability to show that a measurement is
of time between solution preparation and measurement. This
consistent with appropriate national standards through an
interference is discussed further in 8.4.
unbroken chain of comparisons.
5.5 The dosimetric solution is somewhat sensitive to ultra-
3.9 For other terms, see Terminology E 170.
violet light and should be kept in the dark for long-term
4. Significance and Use
storage. No special precautions are required during routine
4.1 The Fricke dosimetry system provides a reliable means handling under normal laboratory lighting conditions, but
for measurement of absorbed dose in water, based on a process strong UV sources such as sunlight should be avoided.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
E 1026
6. Apparatus 7. Reagents
7.1 Purity of Reagents—Reagent grade chemicals shall be
6.1 For the analysis of the dosimetric solution, use a
used in all tests. Unless otherwise indicated, it is intended that
high-precision spectrophotometer capable of measuring absor-
all reagents conform to the specifications of the Committee on
bance values up to 2 with an uncertainty of no more than 61%
Analytical Reagents of the American Chemical Society where
in the region of 300 nm. Use a quartz cuvette with 5 or 10 mm
such specifications are available. Other grades may be used,
path length for spectrophotometric measurement of the solu-
provided it is first ascertained that the reagent is of sufficient
tion. The cuvette capacity must be small enough to allow it to
high purity to permit its use without lessening the accuracy of
be thoroughly rinsed by the dosimeter solution and still leave
the determination.
an adequate amount of that solution to fill the cuvette to the
7.2 Purity of Water—Unless otherwise indicated, references
appropriate level for the absorbance measurement. For dosim-
to water shall be understood to mean reagent water as defined
eter ampoules of 2 mL or less, this may require the use of
by Type II of Specification D 1193.
micro-capacity cuvettes. Other solution handling techniques,
7.2.1 Use of triply-distilled water from coupled all-glass
such as the use of micro-capacity flow cells, may be employed
and silica stills is recommended. Water purity is very important
provided precautions are taken to avoid cross-contamination.
since it is the major constituent of the dosimetric solution, and,
Control the temperature of the dosimetric solution during
therefore, may be the prime source of contamination. Use of
measurement at 25 6 0.2°C. If this is not possible, determine
deionized water is not recommended. Type II reagent water as
the solution temperature during the spectrophotometric analy-
specified in Specification D 1193 is considered to be of
sis and correct the results using (Eq 4) in 10.3.5.
sufficient quality for use in preparing all solutions.
6.2 Use borosilicate glass or equivalent chemically-resistant
NOTE 3—High purity water is commercially available. Such water,
glass to store the reagents and the prepared dosimeter solution.
labeled HPLC (high pressure liquid chromatography) grade, is usually
Clean all apparatus thoroughly before use (see Practice C 912).
sufficiently free of organic impurities to be used in this practice.
6.2.1 One method of cleaning that may be used consists of
7.3 Reagents:
the following steps in sequence:
7.3.1 Ferrous Ammonium Sulfate—(Fe(NH ) (SO ) -
4 2 4 2
6.2.1.1 Ultrasonic cleaning in hot (60°C or higher) distilled
(6H O)).
1 2
water for at least ⁄2 h,
7.3.2 Sodium Chloride (NaCl).
6.2.1.2 Thorough rinsing in hot fuming sulfuric acid,
7.3.3 Sulfuric Acid (H SO ).
2 4
6.2.1.3 Rinsing at least twice with distilled water, and
8. Preparation of Dosimeters
6.2.1.4 Drying in an oven at a temperature of at least 100°C
8.1 Perform the following steps:
for a minimum of 1 h.
8.1.1 Dissolve 0.392 g of ferrous ammonium sulfate,
6.2.1.5 Store the cleaned glassware in a clean, dust-free
Fe(NH ) (SO ) (6H O), and 0.058 g of sodium chloride, NaCl,
4 2 4 2 2
environment. For extreme accuracy, bake the glassware in
−1
in 12.5 mL of 0.4 mol·L sulfuric acid, H SO . Dilute to 1 L
2 4
vacuum at 550°C for at least 1 h (5).
−1
in a volumetric flask with 0.4 mol·L sulfuric acid at 25°C.
6.2.2 As an alternative method, the dosimeter containers
8.1.2 Air saturate the resultant dosimetric solution. One
may be filled with the dosimetric solution and irradiated to a
method for doing this is to bubble high-purity air through the
dose of at least 500 Gy. When a container is needed, pour out
solution, taking care to avoid any possible organic contamina-
the irradiated solution, rinse the container at least three times
tion of the air. Store the dosimetric solution in clean borosili-
with unirradiated solut
...
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