1、ISO/ASTM 51607:2013(E)Standard Practice forUse of an Alanine-EPR Dosimetry System1This standard is issued under the fixed designation ISO/ASTM 51607; the number immediately following the designation indicates theyear of original adoption or, in the case of revision, the year of last revision.1. Scop
2、e1.1 This practice covers dosimeter materials,instrumentation, and procedures for using the alanine-EPRdosimetry system for measuring the absorbed dose in thephoton and electron radiation processing of materials. Thesystem is based on electron paramagnetic resonance (EPR)spectroscopy of free radical
3、s derived from the amino acidalanine.21.2 The alanine dosimeter is classified as a type I dosimeteras it is affected by individual influence quantities in a well-defined way that can be expressed in terms of independentcorrection factors (see ASTM Practice E2628). The alaninedosimeter may be used in
4、 either a reference standard dosimetrysystem or in a routine dosimetry system.1.3 This document is one of a set of standards that providesrecommendations for properly implementing dosimetry inradiation processing, and describes a means of achievingcompliance with the requirements of ASTM E2628 “Prac
5、ticefor Dosimetry in Radiation Processing” for alanine dosimetrysystem. It should be read in conjunction with ASTM E2628.1.4 This practice covers alanine-EPR dosimetry systems fordose measurements under the following conditions:1.4.1 The absorbed dose range is between 1 and 1.5 105Gy.1.4.2 The absor
6、bed dose rate is up to 102Gy s-1for continu-ous radiation fields and up to31010Gy s-1for pulsedradiation fields (1-4).31.4.3 The radiation energy for photons and electrons isbetween 0.1 and 30 MeV (1, 2, 5-8).1.4.4 The irradiation temperature is between 78 C and +70 C (2, 9-12).1.5 This standard doe
7、s not purport to address all of thesafety 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 Stan
8、dards:4E170 Terminology Relating to Radiation Measurements andDosimetryE2628 Practice for Dosimetry in Radiation ProcessingE2701 Guide for Performance Characterization of Dosim-eters and Dosimetry Systems for Use in Radiation Pro-cessing2.2 ISO/ASTM Standards:451261 Practice for Calibration of Routi
9、ne Dosimetry Sys-tems for Radiation Processing51707 Guide for Estimating Uncertainties in Dosimetry forRadiation Processing2.3 ICRU Reports:5ICRU Report 85a Fundamental Quantities and Units forIonizing RadiationICRU Report 80 Dosimetry Systems for Use in RadiationProcessing2.4 Joint Committee for Gu
10、ides in Metrology (JCGM)Reports:JCGM 100:2008, GUM 1995, with minor corrections,Evaluation of measurement data Guide to the Expres-sion of Uncertainty in Measurement6JCGM 100:2008, VIM International vocabulary of metrol-ogy Basis and general concepts and associated terms73. Terminology3.1 Definition
11、s:1This practice is under the jurisdiction of ASTM Committee E61 on RadiationProcessing and is the direct responsibility of Subcommittee E61.02 on DosimetrySystems, and is also under the jurisdiction of ISO/TC 85/WG 3.Current edition approved April 9, 2013. Published June 2013. Originallypublished a
12、s ASTM E 1607 94. Last previous ASTM edition E 1607 961.ASTM E 1607 94 was adopted by ISO in 1998 with the intermediate designationISO 15566:1998(E). The present International Standard ISO/ASTM 51607:2013(E)replaces ISO 15566 and is a major revision of the last previous edition ISO/ASTM516072004(E).
13、2The term “electron spin resonance” (ESR) is used interchangeably withelectron paramagnetic resonance (EPR).3The boldface numbers in parentheses refer to the bibliography at the end of thisstandard.4For referenced ASTM and ISO/ASTM standards, visit the ASTM website,www.astm.org, or contact ASTM Cust
14、omer Service at serviceastm.org. ForAnnual Book of ASTM Standards volume information, refer to the standardsDocument Summary page on the ASTM website.5Available from International Commission on Radiation Units andMeasurements, 7910 Woodmont Ave., Suite 800, Bethesda, MD 20814, U.S.A.6Document produc
15、ed 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).7Document produced by Working Group 2 of the Joint Committee for Guides inMetrology (JCGM/WG 2). Available free of charge at the BIPM website (http:/www.
16、bipm.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 Recommendations issued b
17、y the World Trade Organization Technical Barriers to Trade (TBT) Committee.13.1.1 alanine dosimeterspecified quantity and physicalform of the radiation-sensitive material alanine and any addedinert substance such as a binder.3.1.2 alanine-EPR dosimetry systemsystem used for de-termining absorbed dos
18、e, consisting of alanine dosimeters, anEPR spectrometer and its associated reference materials, andprocedures for the systems use.3.1.3 alanine-EPR dosimeter responsevalue resultingfrom applied adjustments to the EPR signal amplitude.3.1.4 check standarda standard prepared independently ofthe calibr
19、ation standards that is measured to verify the perfor-mance of a dosimetry system.3.1.5 EPR intensity reference materiala stable paramag-netic material whose measurement by EPR is applied to thedosimeter EPR signal amplitude as part of the dosimeterresponse determination.3.1.6 EPR signal amplitudepe
20、ak-to-peak amplitude of thecentral signal of the EPR spectrum.3.1.6.1 DiscussionThis signal is proportional to thealanine-derived free radical concentration in the alanine do-simeter.3.1.7 EPR spectroscopymeasurement of resonant absorp-tion of electromagnetic energy resulting from the transition ofu
21、npaired electrons between different energy levels, upon ap-plication of radio frequencies to a paramagnetic substance inthe presence of a magnetic field.3.1.8 EPR spectrumfirst derivative of the electron para-magnetic absorption spectrum measured as a function of themagnetic field.3.1.9 zero dose am
22、plitudeEPR signal amplitude of anunirradiated alanine dosimeter with the same EPR spectrom-eter parameters used for the lowest measurable absorbed dosevalue.3.2 Definitions of other terms used in this standard thatpertain to radiation measurement and dosimetry may be foundin ASTM Terminology E170. D
23、efinitions in E170 are compat-ible with ICRU Report 85a; that document, therefore, may beused as an alternative reference.4. Significance and use4.1 The alanine-EPR dosimetry system provides a meansfor measuring absorbed dose. It is based on the measurement ofspecific stable free radicals in crystal
24、line alanine generated byionizing radiation.4.2 Alanine-EPR dosimetry systems are used in reference-or transfer-standard or routine dosimetry systems in radiationapplications that include: sterilization of medical devices andpharmaceuticals, food irradiation, polymer modifications,medical therapy an
25、d radiation damage studies in materials (1,13-15).5. Overview5.1 The dosimeter is prepared using -alanine, CH3-CH(NH2)-COOH, in the form of polycrystalline powder.5.2 All stereoisomers of -alanine are suitable for dosim-etry; L-alanine is used most commonly.5.3 Usual physical shapes are films or pel
26、lets (cylinders).NOTE 1Additives, capsules, or film support materials used in thepreparation of dosimeters should not add any significant intrinsic orradiation-induced EPR signal. Examples of suitable binders are ethylene-propylene rubber, gelatin, paraffin, polyethylene, polyethylene vinylacetate,
27、polystyrene, polyvinylpyrrolidone, polyvinyl propylene, andstearin. Lubricants added in the dosimeter manufacturing process areoptional. An example of a suitable lubricant is stearic acid (16-21).5.4 The dosimeter contains crystalline alanine and registersthe absorbed dose by the formation of alanin
28、e-derived freeradicals (22). Identification and measurement of alanine-derived free radicals are performed by EPR spectroscopy.ICRU Report 80 provides information on the scientific basisand historical development of this dosimetry system.5.5 The measurement of free radicals by EPR spectroscopyis non
29、destructive. This can be repeated and hence can be usedfor archival purposes (23-25).6. Influence quantities6.1 Factors other than absorbed dose which influence thedosimeter response are referred to as influence quantities, andare discussed in the following sections (see also ASTM GuideE2701). Examp
30、les of such influence quantities are temperatureand dose rate.6.2 Pre-Irradiation Conditions:6.2.1 Dosimeter Conditioning and PackagingAlanine do-simeter conditioning and packaging may be important undercertain conditions (see 6.2.4).NOTE 2The sorting of alanine pellet dosimeters by mass into sub-lo
31、tswill improve the measurement uncertainty.6.2.2 Time Since ManufactureThere is no known influ-ence of time since manufacture on alanine dosimeters whenstored under recommended conditions.6.2.3 TemperatureThere is no known influence of pre-irradiation temperature. However, it is recommended thatalan
32、ine dosimeters be stored at manufacturer recommendedtemperatures. Exposure to temperatures outside the manufac-turers recommended range should be avoided to reduce thepotential for adverse effects on dosimeter response.6.2.4 Relative HumidityThe humidity during pre-irradiation storage may influence
33、the EPR signal amplitude ofalanine dosimeters (24, 25). The effect of humidity may bereduced by sealing dosimeters in a material impervious towater.6.2.5 Exposure to LightThere is no known influence ofambient light.6.3 Conditions During Irradiation:6.3.1 Irradiation TemperatureThe irradiation temper
34、atureinfluences the EPR signal amplitude of alanine dosimeters.NOTE 3The effect of irradiation temperature on the dosimeter EPRsignal amplitude may be dependent on the dosimeter type. The tempera-ture coefficient, Rt(K-1) is described by the relationship, (m/m)/T,where m is the EPR signal amplitude
35、(in arbitrary units) and T is theirradiation temperature (in K). For dosimeters with L-alanine, a positivetemperature coefficient, expressed in percent, in the range of +0.1 to+0.2 % C-1is typical for irradiation temperatures from 10 C to +70 CISO/ASTM 51607:2013(E)2 ISO/ASTM International 2017 All
36、rights reserved (10, 11, 26-28); refer to Ref (9, 12) for irradiation temperatures below 10C. The temperature coefficient for dosimeters prepared with the DLstereoisomer of alanine is more than 50 % higher than one prepared withL-alanine (29). A summary of published temperature coefficients istabula
37、ted in Ref (26, 29).6.3.2 Absorbed-Dose RateUnder normal radiation pro-cessing conditions there is no measurable effect of absorbeddose rate; however, a dose dependent effect has been charac-terized for alanine dosimeters irradiated to high doses at lowdose rates (30).NOTE 4The dose-rate effect is a
38、bsorbed-dose dependent. Alaninedosimeters irradiated with gamma radiation to absorbed doses 5 kGy atlow dose rates ( 0.5 % can becompensated for by normalizing the dosimeter EPR signal amplitude tothe value of the EPR intensity reference material (see Notes 11 and 12).10.2.8 Determine the absorbed d
39、ose from the normalizeddosimeter response and the appropriate calibration curve (seeSection 9).11. Minimum documentation requirements11.1 Record details of the measurements in accordance withthe users measurement management system.12. Measurement uncertainty12.1 All dose measurements need to be acco
40、mpanied by anestimate of uncertainty. Appropriate procedures are recom-mended in ISO/ASTM 51707 and 51261 (see also GUM).12.2 All components of uncertainty should be included inthe estimate, including those arising from calibration, dosim-eter variability, instrument reproducibility, and the effect
41、ofinfluence quantities.Afull quantitative analysis of componentsof uncertainty is referred to as an uncertainty budget, and isthen often presented in the form of a table. Typically, theuncertainty budget will identify all significant components ofuncertainty, together with their methods of estimatio
42、n, statis-tical distributions and magnitudes (41).12.3 Uncertainty:12.3.1 The estimate of the expanded uncertainty achievablewith measurements made using alanine-EPR as a referencestandard dosimetry system is typically of the order of624 %for a coverage factor k = 2 (which corresponds approximatelyt
43、o a 95 % level of confidence for normally distributed data).12.3.2 The estimate of the expanded uncertainty achievablewith measurements made using alanine-EPR as a routinedosimetry system is typically of the order of 646 % for acoverage factor k = 2 (which corresponds approximately to a95 % level of
44、 confidence for normally distributed data).13. Keywords13.1 absorbed dose; alanine dosimetry; dose measurements;dosimeter; dosimetry system; electron beam; electron para-magnetic resonance; electron spin resonance; EPR dosimeter;EPR dosimetry; ESR dosimeter; gamma radiation; ionizingradiation; irrad
45、iation; photons; radiation; radiation processing;reference standard dosimeter; X radiation; ICS 17.240Bibliography(1) McLaughlin, W. L., Boyd, A. W., Chadwick, K. H., McDonald, J. C.,and Miller, A., Dosimetry for Radiation Processing, Taylor andFrancis, London, U.K., 1989.(2) Regulla, D. F., and Def
46、fner, U., “Dosimetry by ESR Spectroscopy ofAlanine,” Trends in Radiation Dosimetry, W. L. McLaughlin, Ed.,Pergamon Press, Oxford, U.K.; Applied Radiation and Isotopes,Vol33, 1982, p. 1101.(3) Hansen, J. W., and Olsen, K. J.,“ Theoretical and ExperimentalRadiation Effectiveness of the Free Radical Do
47、simeter Alanine toIrradiation with Heavy Charged Particles,” Radiation Research,Vol104, 1985, p. 15.(4) Kudoh, H., Celina, M., Kaye, R. J., Gillen, K. T., and Clough, R. L.,“Response of Alanine Dosimeters at Very High Dose Rate,” AppliedRadiation and Isotopes, Vol 48, 1997, p. 497.(5) Onori, S., Bar
48、tolotta,A., Caccia, B., Indovina, P. L., Milano, F., Renzi,R., Scarpa, G., Caporali, C., and Moscati, M., “Dosimetric Charac-teristics of Alanine-Based ESR Detectors in Electron Beams Used inRadiotherapy,” Radiation Protection Dosimetry, Vol 34, 1990, p. 287.(6) Bergstrand, E. S., Shortt, K. R., Ros
49、s, C. K., and Hole, E. O., “AnInvestigation of the Photon Energy Dependence of the EPR AlanineDosimetry System,” Physics in Medicine and Biology, Vol 48, 2003,p. 1753.ISO/ASTM 51607:2013(E)5 ISO/ASTM International 2017 All rights reserved (7) Zeng, G. G., McCaffrey, J.P., “The response of alanine to a 150 keVx-ray beam,” Radiation Physics and Chemistry, Vol 72, 2005, p. 537
