ISO/ASTM 52116:2002

Practice for dosimetry for a self-contained dry-storage gamma-ray irradiator

ISO/ASTM 52116:2002 outlines dosimetric procedures to be followed with self-contained dry-storage gamma-ray irradiators. ISO/ASTM 52116:2002 covers dosimetry in the use of dry-storage gamma-ray irradiators, namely self-contained dry-storage 137 Cs or 60 Co irradiators (shielded freestanding irradiators). It does not cover underwater pool sources, panoramic gamma-ray sources such as those raised mechanically or pneumatically to irradiate isotropically into a room or through a collimator, nor does it cover self-contained bremsstrahlung x-ray units.

Pratique de la dosimétrie appliquée à un irradiateur gamma renfermant une source auto-protégée entreposée à sec

General Information

• Status: Withdrawn
• Publication Date: 05-Dec-2002
• Withdrawal Date: 05-Dec-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: 22-Mar-2013

Relations

• Revised: ISO/ASTM 52116:2013 - Practice for dosimetry for a self-contained dry-storage gamma irradiator
• Effective Date: 06-Aug-2011

Standards Content (Sample)

INTERNATIONAL ISO/ASTM
STANDARD 52116
First edition
2002-12-15
Practice for dosimetry for a self-
contained dry-storage gamma-ray
irradiator
Pratique de la dosimétrie appliquée à un irradiateur gamma
renfermant une source auto-protégée entreposée à sec
Reference number
ISO/ASTM 52116:2002(E)
© ISO/ASTM International 2002

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ISO/ASTM 52116:2002(E)
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Published in the United States
ii © ISO/ASTM International 2002 – All rights reserved

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ISO/ASTM 52116:2002(E)
Contents Page
1 Scope . 1
2 Referenced documents . 1
3 Terminology . 2
4 Significance and use . 4
5 Types of facilities and modes of operation . 5
6 Radiation source characteristics . 5
7 Dosimetry systems . 5
8 Pre- and post-installation qualification . 6
9 Process qualification . 7
10 Routine sample batch processing . 8
11 Measurement uncertainty . 9
12 Keywords . 9
Annexes (informative) . 10
Bibliography . 13
Figure 1 Example of dose mapping results normalized to a central dose of 100 % . 8
60
Figure A1.1 Basic construction of the GammaCell 220 Co irradiator . 10
Figure A1.2 Basic construction of J.L. Shepherd Mark I irradiator . 10
137
Figure A1.3 Basic construction of the Husman Cs irradiator . 11
Table A2.1 Procedures for testing of self-contained dry-storage irradiators . 12
© ISO/ASTM International 2002 – All rights reserved iii

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ISO/ASTM 52116:2002(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 document 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 52116 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 and A2 of this International Standard are for information only.
iv © ISO/ASTM International 2002 – All rights reserved

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ISO/ASTM 52116:2002(E)
Standard Practice for
Dosimetry for a Self-Contained Dry-Storage Gamma-Ray
1
Irradiator
This standard is issued under the fixed designation ISO/ASTM 52116; 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 2. Referenced documents
1.1 This practice outlines dosimetric procedures to be fol- 2.1 ASTM Standards:
lowed with self-contained dry-storage gamma-ray irradiators. E 170 Terminology Relating to Radiation Measurements
2
If followed, these procedures will help to ensure that calibra- and Dosimetry
tion and testing will be carried out with acceptable precision E 177 Practice for Use of the Terms Precision and Bias in
3
and accuracy and that the samples processed with ionizing ASTM Test Methods
3
radiation from gamma rays in a self-contained dry-storage E 456 Terminology Relating to Quality Statistics
irradiator receive absorbed doses within a predetermined E 1026 Practice for Using the Fricke Reference Standard
2
range. Dosimetry System
1.2 This practice covers dosimetry in the use of dry-storage E 1249 Practice for Minimizing Dosimetry Errors in Radia-
gamma-ray irradiators, namely self-contained dry- tion Hardness Testing of Silicon Electronic Devices Using
137 60
2
storage Cs or Co irradiators (shielded freestanding irra- Co-60 Sources
diators). It does not cover underwater pool sources, panoramic 2.2 ISO/ASTM Standards:
gamma-ray sources such as those raised mechanically or 51204 Practice for Dosimetry in Gamma Irradiation Facili-
2
pneumatically to irradiate isotropically into a room or through ties for Food Processing
a collimator, nor does it cover self-contained bremsstrahlung 51205 Practice for Use of a Ceric-Cerous Sulfate Dosimetry
2
x-ray units. System
1.3 The absorbed dose range for the use of the dry-storage 51261 Guide for Selection and Calibration of Dosimetry
2
self-contained gamma-ray irradiators covered by this practice Systems for Radiation Processing
5
is typically 1 to 10 Gy, depending on the application. The 51275 Practice for Use of a Radiochromic Film Dosimetry
–2 3 2
absorbed-dose rate range typically is from 10 to 10 Gy/min. System
1.4 This practice describes general procedures applicable to 51276 Practice for Use of a Polymethylmethacrylate Do-
2
all self-contained dry-storage gamma-ray irradiators. For pro- simetry System
cedures specific to dosimetry in blood irradiation, see ISO/ 51310 Practice for Use of a Radiochromic Optical
2
ASTM Practice 51939. For procedures specific to dosimetry in Waveguide Dosimetry System
radiation research on food and agricultural products, see 51400 Practice for Characterization and Performance of a
ISO/ASTM Practice 51900. For procedures specific to radia- High-Dose Gamma Radiation Dosimetry Calibration
2
tion hardness testing, see ASTM Practice E 1249. For proce- Laboratory
2
dures specific to the dosimetry in the irradiation of insects for 51401 Practice for Use of a Dichromate Dosimetry System
sterile release programs, see ISO/ASTM Guide 51940. In those 51431 Practice for Dosimetry in Electron and Bremsstrahl-
2
cases covered by ISO/ASTM Practices 51939, 51900, 51940, ung Irradiation Facilities for Food Processing
or ASTM E 1249, those standards take precedence. In addition, 51538 Practice for Use of the Ethanol Chlorobenzene Do-
2
this practice does not cover absorbed-dose rate calibrations of simetry System
radiation protection instrumentation. 51540 Practice for Use of a Radiochromic Liquid Dosim-
2
1.5 This standard does not purport to address all of the etry System
safety concerns, if any, associated with its use. It is the 51607 Practice for the Use of the Alanine-EPR Dosimetry
2
responsibility of the user of this standard to establish appro- System
priate safety and health practices and determine the applica- 51608 Practice for Dosimetry in an X-Ray (Bremsstrahl-
2
bility of regulatory limitations prior to use. ung) Facility for Radiation Processing
51650 Practice for Use of the Cellulose Acetate Dosimetry
2
System
51702 Practice for Dosimetry in a Gamma Irradiation Fa-
1
This practice is under the jurisdiction of ASTM Committee E10 on Nuclear
2
cility for Radiation Processing
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.
2
Current edition approved June 21, 2002. Published Dec. 15, 2002. Originally Annual Book of ASTM Standards, Vol 12.02.
3
published as ASTM E 2116–00. Last previous edition ASTM E 2116–00. Annual Book of ASTM Standards, Vol 14.02.
© ISO/ASTM International 2002 – All rights reserved
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ISO/ASTM 52116:2002(E)
de¯
51707 Guide for Estimating Uncertainties in Dosimetry for
D 5 (1)
2
dm
Radiation Processing
51900 Guide for Dosimetry in Radiation Research on Food
3.1.1.1 Discussion—The discontinued unit for absorbed
2
and Agricultural Products
dose is the rad (1 rad = 100 erg/g = 0.01 Gy). Absorbed dose
2
51939 Practice for Blood Irradiation Dosimetry
is sometimes referred to simply as dose. For a photon source
51940 Guide for Irradiation of Insects for Sterile Release
under conditions of charged particle equilibrium, the absorbed
2
Programs
dose, D, may be expressed as:
2.3 International Commission on Radiation Units and
μ
4 en
Measurements (ICRU) Reports:
D5F · E · (2)
r
ICRU 14 Radiation Dosimetry: X-Rays and Gamma Rays
with Maximum Photon Energies Between 0.6 and 50 MeV
where:
2
ICRU 44 Tissue Substitutes in Radiation Dosimetry and F = particle fluence (particles/m ),
Measurement E = energy of the ionizing radiation (J/particle), and
2
μ /r = mass energy absorption coefficient (m /kg). If
ICRU 51 Quantities and Units in Radiation Protection
en
bremsstrahlung production within the specified
Dosimetry
material is negligible, the mass energy absorption
ICRU 60 Fundamental Quantities and Units for Ionizing
coefficient (μ /r) is equal to the mass energy
Radiation Metrology
en
5
transfer coefficient (μ /r), and absorbed dose is
2.4 ANSI Standards:
tr
equal to kerma if, in addition, charged particle
ANSI N323, Radiation Protection Instrumentation Test and
equilibrium exists.
Calibration
ANSI Report N433.1, Safe Design and Use of Self- 3.1.2 absorbed-dose mapping—measurement of absorbed
dose within a process load using dosimeters placed at specified
Contained, Dry-Source Storage Gamma Irradiators (Cat-
egory I) locations to produce a one-, two-, or three-dimensional distri-
6
bution of absorbed dose, thus rendering a map of absorbed-
2.5 NCRP Publications:
NCRP Report No. 58, Handbook of Radioactivity Measure- dose values.
˙
ments
3.1.3 absorbed-dose rate (D)—the absorbed dose in a
NCRP Report No. 69, Dosimetry of X-Ray and Gamma Ray
material per incremental time interval, that is, the quotient of
Beams for Radiation Therapy in the Energy Range 10 keV
dD by dt.
to 50 MeV
dD
7
˙
2.6 ISO Publications: D 5 (3)
dt
ISO/IEC 17025, General Requirements for the Competence
–1
SI unit: Gy · s .
of Calibration and Testing Laboratories
ISO 11137 Sterilization of Health Care Products—
3.1.3.1 Discussion—The absorbed-dose rate often is speci-
Requirements for Validation and Routine Control-
fied in terms of total value of D as a function of longer time
–1 –1
Radiation Sterilization
intervals, for example, in units of Gy·min or Gy·h .
8
2.7 IAEA Publication:
3.1.4 activity (A)—of an amount of radioactive nuclide in a
IAEA TECDOC-619 X-Ray and Gamma-Ray Standards for
particular energy state at a given time, the quotient of dN by dt,
Detector Calibration
where dN is the expectation value of the number of spontane-
ous nuclear transformations from that energy state in the time
3. Terminology
interval dt (ICRU 60).
3.1 Definitions:
dN
3.1.1 absorbed dose (D)—quantity of ionizing radiation –1
A 5 Unit: s (4)
dt
energy imparted per unit mass of a specified material. The SI
unit of absorbed dose is the gray (Gy), where 1 gray is
The unit of activity, A, is the becquerel (Bq).
equivalent to the absorption of 1 J/kg of the specified material
3.1.4.1 Discussion—The former special unit of activity was
(1 Gy = 1 J/kg). The mathematical relationship is the quotient
the curie (Ci).
of de¯ by dm, where de¯ is the mean incremental energy imparted
10 –1 10
1Ci 5 3.7 3 10 s 5 3.7 3 10 Bq ~exactly! (5)
by ionizing radiation to matter of incremental mass dm (see
The particular energy state is the ground state of the nuclide
ICRU 51).
unless otherwise specified. The activity of an amount of
4
radioactive nuclide in a particular energy state is equal to the
International Commission on Radiation Units and Measurements (ICRU), 7910
Woodmont Ave., Suite 800, Bethesda, MD 20810, U.S.A.
product of the decay constant, l, for that state and the number
5
American National Standards Institute, 25 West 43rd St., New York, NY 10036,
of nuclei in the state (that is, A= Nl) (see decay constant).
U.S.A.
6
3.1.5 calibration—the process whereby the response of a
National Council on Radiation Protection (NCRP), 7910 Woodmont Ave., Suite
800, Bethesda MD 20814, U.S.A. measuring system or measuring instrument is characterized
7
International Organization for Standardization (ISO), 1 rue de Varembé, Case
through comparison with an appropriate standard that is
Postale 56, CH-1211 Geneva 20, Switzerland.
traceable to a nationally or internationally recognized standard.
8
International Atomic Energy Agency (IAEA), Wagrammerstrasse 5, P.O. Box
3.1.6 calibration curve—graphical representation of the
100, A-1400 Vienna, Austria.
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2

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ISO/ASTM 52116:2002(E)
–4 –1
dosimetry system’s response function. was the roentgen (R):1R= 2.58 3 10 C·kg (exactly).
˙
3.1.7 calibration facility—combination of an ionizing radia-
3.1.16 exposure rate (X)—the quotient of dX by dt, where
tion source and its associated instrumentation that provides a
dX is the increment of exposure in the time interval, dt.
uniform and reproducible absorbed dose, or absorbed dose rate,
dX
˙
X 5 (8)
traceable to national or international standards at a specific
dt
location and within a specified material, and that may be used
–1 –1
Unit: C kg s
to derive the dosimetry system’s response function or calibra-
3.1.17 half life (t )—see decay constant.
1/2
tion curve.
3.1.18 irradiator drawer—the cylindrical chamber in which
3.1.7.1 Discussion—Some manufacturers calibrate instru-
the sample to be irradiated is transported by the sample
ments in units of exposure (see 3.1.15).
positioning system back and forth between the loading/
3.1.8 canister—a container, usually an aluminum or steel
unloading and the irradiation positions.
cylinder, used to house the sample, or simulated product,
3.1.19 irradiator rotor—the sample positioning system
during the radiation process.
used to load the sample or sample holder, to rotate it to the
3.1.9 charged particle equilibrium—the condition that ex-
stationary shielded irradiation position and when the irradiation
ists in an incremental volume within a material under irradia-
is completed, to move it to the unloading position.
tion if the kinetic energies and number of charged particles (of
3.1.20 irradiator sample chamber—the accessible enclosed
each type) entering that volume are equal to those leaving that
volume in which a sample or sample holder may be placed in
volume.
the loading/unloading position of the irradiator (typically a
3.1.9.1 Discussion—When electrons are the predominant
gamma cell) prior to irradiation, and which can be transported
charged particle, the term “electron equilibrium” is often used
by the sample positioning system to the irradiation position.
to describe charged particle equilibrium. See also the discus-
3.1.21 irradiator turntable—device used to rotate the irra-
sions attached to the definitions of kerma and absorbed dose in
diated samples during the irradiation to improve (decrease) the
ASTM E 170.
dose uniformity ratio.
3.1.10 decay constant (l)—of a radioactive nuclide in a
3.1.21.1 Discussion—Some irradiator geometries, for ex-
particular energy state, the quotient of dP by dt, where dP is the
ample, with an annular array of radiation sources surrounding
probability of a given nucleus undergoing spontaneous nuclear
the sample, may not need a turntable.
transition from that energy state in the time interval dt (ICRU
3.1.22 isodose curve—lines or surfaces of constant ab-
60).
sorbed dose through a specified medium.
dP
–1
3.1.23 measurement intercomparison—a process by which
l5 Unit: s (6)
dt
an on-site measurement system is evaluated against a measure-
3.1.10.1 Discussion—The quantity (ln 2)/l is commonly
ment of a standard reference device or material that is traceable
called half life, t , of the radioactive nuclide, that is, the time
to a nationally or internationally recognized standard.
1/2
taken for the activity of an amount of radioactive nuclide to
3.1.23.1 Discussion—In radiation processing, reference
become half its initial value.
standard or transfer standard dosimeters are irradiated at one
3.1.11 dose uniformity ratio—ratio of maximum to mini-
irradiation facility, and sent to another for analysis. For
mum absorbed dose within the process load. The concept is
example, an issuing laboratory may send dosimeters to an
also referred to as the max/min dose ratio.
irradiation facility and the irradiated dosimeters are sent back
3.1.12 dosimeter—a device that, when irradiated, exhibits a
to the issuing laboratory for analysis.
quantifiable change in some property of the device which can
3.1.24 kerma (K)—the quotient of dE by dm, where dE is
tr tr
be related to absorbed dose in a given material using appro-
the sum of the initial kinetic energies of all the charged
priate measurement instrumentation and techniques.
particles liberated by uncharged particles in a mass dm of
3.1.13 dosimetry system—a system used for determining
material.
absorbed dose, consisting of dosimeters, measurement instru-
dE
tr –1
K 5 Unit: J kg (9)
ments and their associated reference standards, and procedures
dm
for the system’s use.
The special name for the unit of kerma is gray (Gy).
3.1.14 electron equilibrium—charged particle equilibrium
3.1.25 measurement quality assurance plan—a documented
for electrons.
program for the measurement process that ensures on a
3.1.15 exposure (X)—the quotient of dQ by dm, where the
continuing basis that the overall uncertainty meets the require-
value of dQ is the absolute value of the total charge of the ions
ments of the specific applications. This plan requires traceabil-
of one sign produced in air when all the electrons (negatrons
ity to, and consistency with, nationally or internationally
and positrons) liberated by photons in air of mass dm are
recognized standards.
completely stopped in air (ICRU 60).
3.1.26 measurement traceability—the ability to demonstrate
dQ
by means of an unbroken chain of comparisons that a mea-
X 5 (7)
dm
surement is in agreement within acceptable limits of uncer-
–1
Unit: C kg
tainty with comparable nationally or internationally recognized
3.1.15.1 Discussion—Formerly, the special unit of exposure standards.
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ISO/ASTM 52116:2002(E)
3.1.27 radioactive–source decay—spontaneous nuclear accessible irradiator sample chamber connected with a sample
transformation of an unstable nucleus, with emission of a positioning system, for example, irradiator drawer, rotor, or
particle or photon or both; rate of decay usually is expressed in irradiator turntable, as part of the irradiation device.
terms of radionuclide decay constant or half-life.
4.2 Self-contained dry-storage gamma-ray irradiators can be
3.1.28 reference–standard dosimeter—a dosimeter of high
used for many radiation processing applications, including the
metrological quality, used as a standard to provide measure-
following: calibration of dosimeters; dosimeter studies for
ments traceable to and consistent with measurements made
research; irradiations of relatively small samples for inducing
with primary–standard dosimeters.
desired radiation effects or for radiation process validation
3.1.29 reset timer—an electronic timer, usually digital, that
purposes; irradiation of materials or biological samples for
is equipped as part of the irradiator to time the period for which
process compatibility studies; batch irradiations of microbio-
the sample is to be irradiated. Besides the timer, it contains
logical, botanical, or in-vitro samples; irradiation of small
reset buttons or switches for rezeroing the timer clock, and it is
animals; radiation “hardness” testing of electronics compo-
usually connected to the sample positioning system, irradiator
nents and other materials; and batch radiation processing of
drawer, or irradiator rotor.
relatively small containers of samples, such as blood products,
3.1.30 routine dosimeter—dosimeter used for routine
insect canisters, prosthetic devices, and pharmaceuticals.
absorbed-dose measurement, calibrated against a primary-,
NOTE 1—In the case of irradiated health care products, pharmaceuti-
reference-, or transfer-standard dosimeter.
cals, foodstuffs, animals and plants, the assurance that they are properly
3.1.31 sample holder—a relatively small container that fits
irradiated is of crucial importance. The irradiator operator must demon-
at a fixed or repeatable position in the enclosed chamber of the
strate by means of accurate absorbed dose measurements in sample, or in
irradiation device that serves to hold the sample in a reproduc-
simulated product, that the specified absorbed dose is achieved (see
ible way, and, in the case of dosimeters being calibrated, serves
ISO/ASTM Guide 51261, ISO/ASTM Practices 51204, 51400, 51702, and
ISO 11137). For most applications, the absorbed dose is expressed as
to provide standardized electronic equilibrium conditions dur-
absorbed dose in water (see ISO/ASTM Guide 51261). For conversion of
ing irradiation. The sample holder often is referred to as the
absorbed dose in water to that in other materials, for example, silicon,
product holder.
solid-state devices, polymers, see Annex A1 of ISO/ASTM Guide 51261.
3.1.32 simulated product—a mass of material with attenu-
ation and scattering properties similar to those of the product, 4.3 Self-contained dry-storage gamma-ray irradiators con-
material, or substance to be irradiated. tain a sealed source, or an array of sealed sources completely
held in a dry container constructed of solid materials. The
3.1.32.1 Discussion—Simulated product often is used dur-
ing irradiator characterization as a substitute for the actual sealed sources are shielded at all times, and human access to
product, material or substance to be irradiated. When used in the chamber undergoing irradiation is not physically possible
routine production runs, it is sometimes referred to as compen- due to design configuration (see ANSI N433.1).
sating dummy. When used for absorbed-dose mapping, simu-
4.4 For each irradiator, an absorbed–dose rate at a reference
lated product is sometimes referred to as a phantom material.
position within the sample or sample holder is measured. That
3.1.33 transfer–standard dosimeter—a dosimeter, often a
measurement is used to calculate the timer setting required to
reference–standard dosimeter, suitable for transport between
deliver the specified absorbed dose. The irradiator manufac-
different locations, used to compare absorbed-dose measure-
turer may perform reference-standard measurements and dose-
ments.
mapping measurements within the irradiation chamber.
3.1.34 transit dose—absorbed dose delivered to irradiated
NOTE 2—For reference–standard dosimetry, the absorbed dose and
samples while the item to be irradiated in a fixed or turntable
absorbed-dose rate can be expressed in water or other material which has
position moves into or out of that position or while the movable
similar radiation absorption properties to that of the samples or dosimeters
source moves into or out of its irradiation position.
being irradiated. In some cases, the reference–standard dosimetry may be
3.1.34.1 Discussion—See ISO/ASTM Guide 51261 for de-
performed using ionization chambers, and may be calibrated in terms of
–1
tails. exposure (C kg ), or absorbed dose in air, water or tissue (gray).
Measurements performed in terms of exposure apply to ionization in air,
3.1.35 validation—establishment of documented evidence
and care should be taken to apply that measurement to the sample being
which provides a high degree of assurance that a specified
irradiated.
process will consistently produce a product meeting its prede-
termined specifications and quality attributes.
4.5 Dosimetry carried out with such sources may be part of
3.2 Definitions of other terms used in this standard that
a measurement quality assurance program that is applied to
pertain to radiation measurement and dosimetry may be found
ensure that the radiation process, test or calibration meets
9
in ASTM Terminology E 170. Definitions in ASTM Terminol-
predetermined specifications (1).
ogy E 170 are compatible with ICRU 60; that document,
4.6 Absorbed-dose mapping for establishing the locations of
therefore, may be used as an alternative reference.
minimum (D ) and maximum (D ) doses usually is per-
min max
formed using the sample or simulated product (see 9.3).
4. Significance and use
4.1 Self-contained dry-storage gamma-ray irradiators con-
137 60
tain radioactive sources, namely Cs or Co, that emit
9
ionizing electromagnetic radiation (gamma rays), under prop-
The boldface numbers in parentheses refer to the bibliography at the end of this
standard.
erly shielded conditions. These irradiators have an enclosed,
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ISO/ASTM 52116:2002(E)
5. Types of facilities and modes of operation 7.2 Description of Dosimeter Classes:
7.2.1 Dosimetry systems are used to measure absorbed
5.1 Self-Contained Gamma Irradiators—Typical self-
dose. They consist of the dosimeters, measurement instruments
contained dry-storage gamma-ray irradiators are illustrated in
and their associated reference standards, and the procedures for
Annex A1. These irradiators house the radiation source(s) in a
the system’s use.
protective lead shield (or other appropriate solid high atomic-
7.2.2 Dosimeters may be divided into four basic classes
number material), and usually have a sample positioning
according to their accuracy and areas of application: primary-
mechanism tied to an accurate calibrated reset timer to lower or
–standard, reference–standard, transfer–standard, and routine
rotate the sample holder from the load/unload position to the
dosimeters. ISO/ASTM Guide 51261 provides detailed in
...