1、Practice for dosimetry in an electron beam facility for radiation processing at energies between 80 and 300 keV Pratique de la dosimtrie dans une installiation de traitement par irradiation utilisant un faisceau dlectrons dnergies comprises entre 80 keV et 300 keV ISO/ASTM 51818 !“#$% :5;2 *5*C2B9“!
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4、berimmediatelyfollowingthedesignationindicatesthe year of original adoption or, in the case of revision, the year of last revision. 1. Scope 1.1 This practice covers dosimetric procedures to be fol- lowedininstallationqualication,operationalqualicationand performance qualication (IQ, OQ, PQ), and ro
5、utine process- ing at electron beam facilities to ensure that the product has beentreatedwithanacceptablerangeofabsorbeddoses.Other procedures related to IQ, OQ, PQ, and routine product pro- cessing that may inuence absorbed dose in the product are also discussed. 1.2 Theelectronbeamenergyrangecover
6、edinthispractice isbetween80and300keV,generallyreferredtoaslowenergy. 1.3 Dosimetry is only one component of a total quality assurance program for an irradiation facility. Other measures may be required for specic applications such as medical device sterilization and food preservation. 1.4 Other spe
7、cic ISO and ASTM standards exist for the irradiationoffoodandtheradiationsterilizationofhealthcare products.Fortheradiationsterilizationofhealthcareproducts, see ISO 11137. In those areas covered by ISO 11137, that standard takes precedence. For food irradiation, see ISO 14470:2011. Information abou
8、t effective or regulatory dose limitsforfoodproductsisnotwithinthescopeofthispractice (seeASTM F1355 and F1356). 1.5 Thisdocumentisoneofasetofstandardsthatprovides recommendations for properly implementing and utilizing dosimetry in radiation processing. It is intended to be read in conjunction with
9、 ASTM E2232, “Practice for Dosimetry in Radiation Processing”. 1.6 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 appro- priate safety and health practices and determine the app
10、lica- bility of regulatory limitations prior to use. 2. Referenced documents 2.1 ASTM Standards: 2 E170 TerminologyRelatingtoRadiationMeasurementsand Dosimetry E2232 Guide for Selection and Use of Mathematical Meth- odsforCalculatingAbsorbedDoseinRadiationProcessing Applications E2303 Guide for Abso
11、rbed-Dose Mapping in Radiation Processing Facilities E2628 Practice for Dosimetry in Radiation Processing E2701 Guide for Performance Characterization of Dosim- etersandDosimetrySystemsforUseinRadiationProcess- ing F1355 Guide for Irradiation of Fresh Agricultural Produce as a Phytosanitary Treatmen
12、t F1356 Practice for Irradiation of Fresh and Frozen Red Meat and Poultry to Control Pathogens and Other Micro- organisms 2.2 ISO Standards: 3 11137-1:2006 Sterilization of health care productsRadia- tionPart 1: Requirements for development, validation and routine control of a sterilization process
13、for medical devices 14470:2011 Food irradiationRequirements for the devel- opment, validation and routine control of the ionizing radiation used for the treatment of food 17025:2005 General requirements for the competence of testing and calibration laboratories 2.3 ISO/ASTM Standards: 2 51261 Practi
14、ce for Calibration of Routine Dosimetry Sys- tems for Radiation Processing 51275 Practice for Use of a Radiochromic Film Dosimetry System 51607 Practice for Use of anAlanine-EPR Dosimetry Sys- tem 51649 Practice for Dosimetry in an Electron Beam Facility 1 This practice is under the jurisdiction ofA
15、STM Committee E61 on Radiation Processing and is the direct responsibility of Subcommittee E61.03 on Dosimetry Application, and is also under the jurisdiction of ISO/TC 85/WG 3. Current edition approved April 9, 2013. Published June 2013. Originally published as ASTM E181896. Last previous ASTM edit
16、ion E181896 1 . ASTM E181896 1 was adopted in 1998 with the intermediate designation ISO 15573:1998(E). The present Third Edition of International Standard ISO/ASTM 51818:2013(E) is a major revision of the Second Edition of ISO/ASTM 51818:2009(E). 2 For referenced ASTM standards, visit the ASTM webs
17、ite, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolumeinformation,refertothestandardsDocumentSummarypageon theASTM website. 3 Available from International Organization for Standardization (ISO), 1, ch. de la Voie-Creuse, CP 56, CH-1211 Geneva 2
18、0, Switzerland, http:/www.iso.org. 1 orhasbeenformallyaccreditedto ISO/IEC 17025; or has a quality system consistent with the requirements of ISO/IEC 17025. 3.1.3 average beam currenttime-averaged electron beam current. 3.1.4 beam widthdimension of the irradiation zone per- pendiculartothedirectiono
19、fproductmovement,ataspecied distance from the accelerator window. 3.1.5 depth-dose distributionvariation of absorbed dose with depth from the incident surface of a material exposed to a given radiation. 3.1.6 dosimeterdevice that, when irradiated, exhibits a quantiable change that can be related to
20、absorbed dose in a givenmaterialusingappropriatemeasurementinstrumentsand procedures. 3.1.7 dosimetry systemsystem used for determining ab- sorbed dose, consisting of dosimeters, measurement instru- mentsandtheirassociatedreferencestandards,andprocedures for the systems use. 3.1.8 electron beam ener
21、gykinetic energy of the acceler- ated electrons in the beam. 3.1.9 traceabilityproperty of the result of a measurement or the value of a standard whereby it can be related to stated references, usually national or international standards, through an unbroken chain of comparisons all having stated un
22、certain- ties. 3.1.10 uncertaintyparameter associated with the result of a measurement that characterizes the dispersion of the values thatcouldreasonablybeattributedtothemeasurandorderived quantity (see ISO/ASTM Guide 51707). 3.2 Denitions of Terms Specic to This Standard: 3.2.1 D absorbeddosetowat
23、erintherstmicrometerof water equivalent absorbing material (1). 5 3.2.1.1 DiscussionD is a term used by an approved laboratory to specify reported surface dose values of transfer standarddosimetersbasedonadjustmentsmadetoaccountfor user site specic calibration irradiation conditions. 3.2.2 linearpro
24、cessrateproductlengthirradiatedperunit time to deliver a given dose. 3.2.3 mass process rateproduct mass irradiated per unit time to deliver a given dose. 3.2.4 area process rateproduct area irradiated per unit time to deliver a given dose. 3.3 Denitions of other terms used in this standard that per
25、tain to radiation measurement and dosimetry may be found in Terminology E170. Denitions in Terminology E170 are compatible with ICRU Report 85a; that document, therefore, may be used as an alternative reference. 4. Signicance and use 4.1 A variety of irradiation processes uses low energy electron be
26、am facilities to modify product characteristics. Dosimetry requirements, the number and frequency of mea- surements,andrecordkeepingrequirementswillvarydepend- ing on the type and end use of the products being processed. Dosimetry is often used in conjunction with physical, chemi- cal, or biological
27、 testing of the product, to help verify specic treatment parameters. NOTE 1In many cases dosimetry results can be related to other quantitative product properties; for example, gel fraction, melt ow, modulus, molecular weight distribution, or cure analysis tests. 4.2 Radiation processing specication
28、s usually include a minimum or maximum absorbed dose limit, or both. For a given application these limits may be set by government regulation or by limits inherent to the product itself. 4.3 Criticalprocessparametersmustbecontrolledtoobtain reproducible dose distribution in processed materials. The
29、electron beam energy, beam current, beam width and process line speed (conveying speed) affect absorbed dose. 4.4 Before any electron beam facility can be routinely utilized, it must be validated to determine its effectiveness. This involves testing of the process equipment, calibrating the measurin
30、g instruments and the dosimetry system, and demon- strating the ability to consistently deliver the required dose within predetermined specications. 4.5 In order for a dosimetry system to be effective in low-energy electron irradiation applications and to measure doseswithanacceptablelevelofuncertai
31、nty,itisnecessaryto calibratethedosimetrysystemunderirradiationconditionsthat are consistent with those encountered in routine use. For example, a dosimetry system calibration conducted using 4 AvailablefromtheInternationalCommissiononRadiationUnitsandMeasure- ments, 7910 WoodmontAve., Suite 800, Bethesda, MD 20814, U.S.A. 5 Theboldfacenumbersinparenthesesrefertothebibliographyattheendofthis standard. ISO/ASTM 51818:2013(E) 2 & (D()*+
