1、ISO/ASTM 52116:2013(E)Standard Practice forDosimetry for a Self-Contained Dry-Storage GammaIrradiator1This standard is issued under the fixed designation ISO/ASTM 52116; the number immediately following the designation indicates theyear of original adoption or, in the case of revision, the year of l
2、ast revision.1. Scope1.1 This practice outlines dosimetric procedures to be fol-lowed with self-contained dry-storage gamma irradiators. Forirradiators used for routine processing, procedures are given toensure that product processed will receive absorbed doseswithin prescribed limits.1.2 This pract
3、ice covers dosimetry in the use of dry-storagegamma irradiators, namely self-contained dry-storage137Cs or60Co irradiators (shielded freestanding irradiators). It does notcover underwater pool sources, panoramic gamma sources, nordoes it cover self-contained bremsstrahlung X-ray units.1.3 The absorb
4、ed-dose range for the use of the dry-storageself-contained gamma irradiators covered by this practice istypically 1 to 105Gy, depending on the application. Theabsorbed-dose rate range typically is from 102to 103Gy/min.1.4 For irradiators supplied for specific applications, spe-cific ISO/ASTM or ASTM
5、 practices and guides providedosimetric procedures for the application. For proceduresspecific to dosimetry in blood irradiation, see ISO/ASTMPractice 51939. For procedures specific to dosimetry in radia-tion research on food and agricultural products, see ISO/ASTMPractice 51900 . For procedures spe
6、cific to radiation hardnesstesting, see ASTM Practice E1249. For procedures specific tothe dosimetry in the irradiation of insects for sterile releaseprograms, see ISO/ASTM Guide 51940. In those cases coveredby ISO/ASTM 51939, 51900 , 51940, or ASTM E1249, thosestandards take precedence.1.5 This doc
7、ument is one of a set of standards that providesrecommendations for properly implementing and utilizingdosimetry in radiation processing. It is intended to be read inconjunction with ASTM E2628, “Practice for Dosimetry inRadiation Processing”.1.6 This standard does not purport to address all of thes
8、afety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced documents2.1 ASTM Standards:2E170 Terminology Relating to
9、Radiation Measurements andDosimetryE1249 Practice for Minimizing Dosimetry Errors in Radia-tion Hardness Testing of Silicon Electronic Devices UsingCo-60 SourcesE2628 Practice for Dosimetry in Radiation ProcessingE2701 Guide for Performance Characterization of Dosim-eters and Dosimetry Systems for U
10、se in Radiation Pro-cessing2.2 ISO/ASTM Standards:251261 Practice for Calibration of Routine Dosimetry Sys-tems for Radiation Processing51539 Guide for Use of Radiation-Sensitive Indicators51707 Guide for Estimating Uncertainties in Dosimetry forRadiation Processing51900 Guide for Dosimetry in Radia
11、tion Research on Foodand Agricultural Products51939 Practice for Blood Irradiation Dosimetry51940 Guide for Dosimetry for Sterile Insects Release Pro-grams2.3 International Commission on Radiation Units and Mea-surements (ICRU) Reports:3ICRU 85a Fundamental Quantities and Units for IonizingRadiation
12、2.4 ANSI Standards:4ANSI/HPS N43.7 Safe Design and Use of Self-Contained,Dry Source Storage Gamma Irradiators (Category I)2.5 Joint Committee for Guides in Metrology (JCGM)Reports:JCGM 100:2008, GUM 1995 with minor corrections, Evalu-ation of measurement data Guide to the Expression of1This practice
13、 is under the jurisdiction of ASTM Committee E61 on RadiationProcessing and is the direct responsibility of Subcommittee E61.04 on SpecialtyApplication, and is also under the jurisdiction of ISO/TC 85/WG 3.Current edition approved Aug. 16, 2012. Published April 2013. Originallypublished as ASTM E 21
14、1600. Last previous edition ASTM E 211600. Thepresent International Standard ISO/ASTM 52116:2013(E) replaces E 2116-00 and isa major revision of the last previous edition ISO/ASTM 52116:2002:(E).2For referenced ASTM and ISO/ASTM standards, visit the ASTM website,www.astm.org, or contact ASTM Custome
15、r Service at serviceastm.org. ForAnnual Book of ASTM Standards volume information, refer to the standardsDocument Summary page on the ASTM website.3International Commission on Radiation Units and Measurements (ICRU), 7910Woodmont Ave., Suite 800, Bethesda, MD 20810, U.S.A.4Available from the Health
16、Physics Society, http:/hps.org. ISO/ASTM International 2017 All rights reservedThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Rec
17、ommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1Uncertainty in Measurement5JCGM 100:2008, VIM International vocabulary of metrol-ogy Basis and general concepts and associated terms63. Terminology3.1 Definitions:3.1.1 absorbed-dose mappingmeasurement o
18、f absorbeddose within an irradiated product to produce a one-, two-, orthree-dimensional distribution of absorbed dose, thus renderinga map of absorbed-dose values.3.1.2 calibrationVIM, 6.11 set of operations underspecified conditions, which establishes the relationship be-tween values indicated by
19、a measuring instrument or measur-ing system, and the corresponding values realised by standardstraceable to a nationally or internationally recognised labora-tory.3.1.2.1 DiscussionCalibration conditions include environ-mental and irradiation conditions present during irradiation,storage and measure
20、ment of the dosimeters that are used for thegeneration of a calibration curve. To achieve stable environ-mental conditions, it may be necessary to condition thedosimeters before performing the calibration procedure.3.1.3 dose uniformity ratioratio of the maximum to theminimum absorbed dose within th
21、e irradiated product.3.1.4 measurement management systemset of interrelatedor interacting elements necessary to achieve metrologicalconfirmation and continual control of measurement processes.3.1.5 transit doseabsorbed dose delivered to a product (ora dosimeter) while it travels between the non-irra
22、diationposition and the irradiation position, or in the case of amovable source while the source moves into and out of itsirradiation position.3.2 Definitions of other terms used in this standard thatpertain to radiation measurement and dosimetry may be foundin ASTM Terminology E170. Definitions in
23、ASTM Terminol-ogy E170 are compatible with ICRU 85a; that document,therefore, may be used as an alternative reference.4. Significance and use4.1 The design and operation of a self-contained irradiatorshould ensure that reproducible absorbed doses are obtainedwhen the same irradiation parameters are
24、used. Dosimetry isperformed to determine the relationship between the irradiationparameters and the absorbed dose.4.1.1 For most applications, the absorbed dose is expressedas absorbed dose to water (see ISO/ASTM Practice 51261).For conversion of absorbed dose to water to that to othermaterials, for
25、 example, silicon, see Annex A1 of ISO/ASTMPractice 51261.4.2 Self-contained dry-storage gamma irradiators containproperly shielded radioactive sources, namely137Cs or60Co,that emit ionizing electromagnetic radiation (gamma radia-tion). These irradiators have an enclosed, accessible irradiatorsample
26、 chamber connected with a sample positioning system,for example, irradiator drawer, rotor, or irradiator turntable, aspart of the irradiation device.4.3 Self-contained dry-storage gamma irradiators can beused for many radiation processing applications, including thecalibration irradiation of dosimet
27、ers; studies of dosimeterinfluence quantities; radiation effects studies, and irradiation ofmaterials or biological samples for process compatibilitystudies; batch irradiations of microbiological, botanical, orin-vitro samples; irradiation of small animals; radiation “hard-ness” testing of electroni
28、cs components and other materials;and batch radiation processing of containers of samples.NOTE 1Self-contained dry-storage gamma irradiators contain a sealedradiation source, or an array of sealed radiation sources securely held in adry container constructed of solid materials. The sealed radiation
29、sourcesare shielded at all times, and human access to the chamber undergoingirradiation is not physically possible due to the irradiators designconfiguration (see ANSI/HPS N43.7).NOTE 2For referencestandard dosimetry, the absorbed dose andabsorbed-dose rate can be expressed in water or other materia
30、l which hassimilar radiation absorption properties to that of the samples or dosimetersbeing irradiated. In some cases, the reference-standard dosimetry may beperformed using ionization chambers, and may be calibrated in terms ofexposure (C kg1), or absorbed dose to air, water or tissue (Gy).Measure
31、ments performed in terms of exposure apply to ionization in air,and care should be taken to apply that measurement to the sample beingirradiated.5. Types of facilities and modes of operation5.1 Facility TypesTypical self-contained dry-storagegamma irradiators are illustrated in Annex A1. These irrad
32、ia-tors house the radiation source(s) in a protective lead shield (orother appropriate material), and usually have a sample posi-tioning mechanism tied to an accurate calibrated reset timer tolower or rotate the sample holder from the load/unload positionto the irradiation position and back to the l
33、oad/unload position.Details on the calibration of dosimetry systems and dosemapping in such irradiators may be found, respectively inISO/ASTM Guide 51261 and in this practice. Details on thedesigns of such irradiators and on safety considerations in theuse of such irradiators may be found in ANSI/HP
34、S N43.7.5.2 Modes of OperationThree common modes of opera-tion are described. This does not purport to include all modesof operation.5.2.1 One method of use is to rotate the sample holder on anirradiator turntable in front of the source such that the onlypoints that remain a fixed distance from the
35、source are along anaxis of rotation (ANSI/HPS N43.7).5.2.2 A second method is to distribute the source in anannular array, resulting in a relatively uniform absorbed-dosedistribution. In this design, the irradiator turntable normallywould not be necessary.5.2.3 A third method is to use opposed sourc
36、es withappropriate beam flattening to obtain a uniform dose through-out the sample.5Document produced by Working Group 1 of the Joint Committee for Guides inMetrology (JCGM/WG 1). Available free of charge at the BIPM website (http:/www.bipm.org).6Document produced by Working Group 2 of the Joint Com
37、mittee for Guides inMetrology (JCGM/WG 2). Available free of charge at the BIPM website (http:/www.bipm.org).ISO/ASTM 52116:2013(E)2 ISO/ASTM International 2017 All rights reserved 6. Radiation source characteristics6.1 The radiation sources used in the irradiation devicesconsidered in this practice
38、 consist of sealed elements of60Coor137Cs, which are typically linear rods or pencils arrangedsingly or in a planar array or cylindrical array.6.2 Cobalt-60 emits photons with energies of approximately1.17 and 1.33 MeV in nearly equal proportions; cesium-137emits photons with energies of approximate
39、ly 0.662 MeV.6.3 The radioactive decay half-lives for60Co and137Cs areregularly reviewed and updated. The most recent publicationby the National Institute of Standards and Technology7gavevalues of 1925.20 (6 0.25) days for60Co and 11018.3 (6 9.5)days for137Cs. In addition, the137Cs radiation source
40、maycontain radioimpurities which should be qualified by the sourcemanufacturer.6.4 For pure60Co and137Cs gamma sources, the onlyvariation in the source strength is the known reduction in theactivity caused by radioactive decay. The reduction in thesource strength and the required increase in the irr
41、adiation timeto deliver the same dose may be calculated or obtained fromtables provided by the irradiator manufacturer.7. Dosimetry systems7.1 The basic requirements that apply when making ab-sorbed dose measurements are given in ASTM E2628. ASTME2628 also provides guidance on the selection of dosim
42、etrysystems and describes the classification of dosimeters based ontwo criteria. Users are directed to other standards that providespecific information on individual dosimetry systems, calibra-tion methods, and uncertainty estimation.NOTE 3The operation of a self-contained dry-storage irradiator,abs
43、orbed-dose measurements made in the sample under controlled envi-ronmental and geometrical conditions of calibration, testing, or processingprovide an independent quality control record.8. Installation qualification (IQ)8.1 ObjectiveThe purpose of an installation qualification(IQ) program is to obta
44、in and document evidence that theirradiator and measurement instruments have been deliveredand installed in accordance with their specifications. IQ in-cludes documentation of the irradiator equipment and measure-ment instruments; establishment of testing, operation andcalibration procedures for the
45、ir use; and verification that theinstalled irradiator equipment and measurement instrumentsoperate according to specification.NOTE 4Table A2.1 gives some recommended steps in the followingareas: installation qualification, operational qualification, performancequalification, and routine product proc
46、essing.8.2 Equipment DocumentationEstablish and document anIQ program that includes descriptions of the instrumentationand equipment installed at the facility. This documentationshall be retained for the life of the facility. At a minimum, itshall include:8.2.1 A description of the irradiators speci
47、fications, char-acteristics and parameters, including any modifications madeduring or after installation,8.2.2 A description of the location of the irradiator withinthe operators premises,8.2.3 Operating instructions and standard operating proce-dures for the irradiator and associated measurementins
48、truments,8.2.4 Licensing and safety documents and procedures, in-cluding those required by regulatory and occupational healthand safety agencies,8.2.5 A description of a calibration program to ensure thatall processing equipment that may influence absorbed-dosedelivery is calibrated periodically (fo
49、r example, the timermechanism),8.2.6 Operating procedures and calibration procedures forassociated measurement instruments or systems.8.3 Equipment Testing and CalibrationTest all processingequipment and instrumentation that may influence absorbeddose in order to verify satisfactory operation of the irradiatorwithin the design specifications.8.3.1 Implement a documented calibration program to en-sure that all processing equipment and instrumentation thatmay influence absorbed-
