1、Designation: D7283 13Standard Test Method forAlpha and Beta Activity in Water By Liquid ScintillationCounting1This standard is issued under the fixed designation D7283; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of la
2、st revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the measurement of grossalpha- and beta- activity concentrations in a homogeneouswater sample. I
3、t is applicable to alpha emitters with activityconcentration levels above 0.11 Bq/L (3 pCi/L) and betaemitters with activity concentration levels above 0.15 Bq/L (4pCi/L). This test method is not applicable to samples contain-ing radionuclides that are volatile under conditions of theanalysis.1.2 Th
4、is test method may also be used for the directmeasurement of gross alpha- and beta- activity concentrationsin homogeneous water samples with alpha emitter activityconcentration levels above 1.8 Bq/L (50 pCi/L) and betaemitter activity concentration levels above 3.7 Bq/L (100pCi/L).1.3 This test meth
5、od was tested using single-operatortests.2,31.4 Standard methods under the jurisdiction of ASTM Com-mittee D19 may be published for a limited time preliminary tothe completion of full collaborative study validation. Suchstandards are deemed to have met all other D19 qualifyingrequirements but have n
6、ot completed the required validationstudies to fully characterize the performance of the TestMethod across multiple laboratories and matrices. Preliminarypublication is done to make current technology accessible tousers of standards, and to solicit additional input from the usercommunity.1.5 The val
7、ues stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.6 This standard does 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 sa
8、fety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:4D1129 Terminology Relating to WaterD1125 Test Methods for Electrical Conductivity and Resis-tivity of WaterD1193 Specification for Reagent WaterD1890 Test Meth
9、od for Beta Particle Radioactivity of WaterD1943 Test Method for Alpha Particle Radioactivity ofWaterD3370 Practices for Sampling Water from Closed ConduitsD3648 Practices for the Measurement of RadioactivityD3856 Guide for Management Systems in LaboratoriesEngaged in Analysis of WaterD4448 Guide fo
10、r Sampling Ground-Water Monitoring WellsD5847 Practice for Writing Quality Control Specificationsfor Standard Test Methods for Water AnalysisD6001 Guide for Direct-Push Groundwater Sampling forEnvironmental Site Characterization2.2 Other Standards and Publications:EPA 900.0 Gross Alpha and Gross Bet
11、a Radioactivity inDrinkingWater, from Prescribed Procedures for Measure-ment of Radioactivity in Drinking Water (EPA-600/4-80-032)5Standard Methods 7110C Coprecipitation Method for GrossAlpha Radioactivity in Drinking Water6Standard Methods 8010E Table 8010: Recommended Com-position for Reconstitute
12、d Fresh Water61This test method is under the jurisdiction of ASTM Committee D19 on Waterand is the direct responsibility of Subcommittee D19.04 on Methods of Radiochemi-cal Analysis.Current edition approved Feb. 1, 2013. Published April 2013. Originallyapproved in 2006. Last previous edition approve
13、d in 2006 as D7283 06. DOI:10.1520/D7283-13.2Wong, C. T., Soliman, V. M., and Perera, S. K., Journal of Radioanalytical andNuclear Chemistry, Vol 264, No. 2, 2005, pp. 357363.3Ruberu, S.R., Liu, Y.G., and Perera, S.K., Health Physics, Vol 95, No. 4,October 2008, pp. 397406.4For referenced ASTM stand
14、ards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.5Available from United States Environmental Protection Association (EPA),Ariel Rios Bld
15、g., 1200 Pennsylvania Ave., NW, Washington, DC 20460, http:/www.epa.gov.6Available from American Water Works Association (AWWA), 6666 W. QuincyAve., Denver, CO 80235, http:/www.awwa.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1
16、ISO 9696 Water QualityMeasurement of Gross AlphaActivity in Non-saline WaterThick Source Method7ISO 11704:2010 Water QualityMeasurement of Gross Al-pha and BetaActivity Concentration in non-saline water Liquid Scintillation Counting Method73. Terminology3.1 DefinitionsFor definitions of terms used i
17、n this testmethod, refer to Terminology D1129. For terms not defined inthis test method or in Terminology D1129, reference may bemade to other published glossaries.3.2 Definitions of Terms Specific to This Standard:3.2.1 alpha-to-beta spillover, nin the measurement ofradioactivity, for a given emitt
18、ing source, that fraction of alphaparticles that are misclassified as beta particles by the counter.3.2.2 alpha particle detection effciency, nin the measure-ment of radioactivity, for a given emitting source, that fractionof alpha particles that are identified as alpha particles by thecounter.3.2.3
19、 beta-to-alpha spillover, nin the measurement ofradioactivity, for a given emitting source, that fraction of betaparticles that are misclassified as alpha particles by the counter.3.2.4 beta energy, maximum, nthe maximum energy of thebeta particle energy spectrum produced during beta decay of agiven
20、 radionuclide.3.2.4.1 DiscussionSince a given beta emitter may decayto several different nuclear energy levels of the progeny, morethan one maximum energy may be listed for a given radionu-clide.3.2.5 beta particle detection effciency, nin the measure-ment of radioactivity, for a given emitting sour
21、ce, that fractionof beta particles that are identified as beta particles by thecounter.3.2.6 detector background, nin the measurement ofradioactivity, the counting rate resulting from factors otherthan the radioactivity of the sample and reagents used.3.2.6.1 DiscussionDetector background varies wit
22、h thelocation, shielding of the detector, and the electronics; suchbackground includes cosmic rays, contaminating radioactivity,and electronic noise.3.2.7 figure of merit, na numerical quantity based on oneor more characteristics of a system or device, representing ameasure of efficiency or effectiv
23、eness; figure of merit isgenerally calculated as the square of the efficiency divided bythe background.3.2.8 gross alpha, nin the measurement of radioactivity, asemi-quantitative estimate of the combined activity of alpha-emitting radionuclides in a test sample.3.2.9 gross beta, nin the measurement
24、of radioactivity, asemi-quantitative estimate of the combined activity of beta-emitting radionuclides in a test sample.3.2.10 homogeneous water sample, nwater in which thealpha and beta activity is uniformly dispersed throughout thevolume of water sample and remains so until the measurementis comple
25、ted or until the sample is evaporated or precipitatingreagents are added to the sample.3.2.11 reagent background, nin the measurement of ra-dioactivity of water samples, the counting rate observed whena sample is replaced by mock sample salts or by reagentchemicals used for chemical separations that
26、 contain noanalyte.3.2.11.1 DiscussionReagent background varies with thereagent chemicals and analytical methods used and may varywith reagents from different manufacturers and from differentprocessing lots.4. Summary of Test Method4.1 The test sample is reduced by evaporation, transferred toa scint
27、illation vial and mixed with a suitable liquid scintillationcocktail. Gross alpha- and beta- activity concentrations aremeasured simultaneously by liquid scintillation using alpha/beta discrimination. By optimizing the alpha/betadiscriminator, a high efficiency of alpha- and beta- particledetection
28、can be achieved with acceptable misclassification ofbeta particles into the alpha multi-channel analyzer (MCA) andalpha particles into the beta MCA.The alpha- and beta- particleefficiency and spillover calibrations of the liquid scintillationsystem are determined by using known activities of establi
29、shedreference nuclides in test sources having cocktail-solvent ratioscomparable to that of the test samples. Some commonlyemployed reference standards include241Am,239Pu,230Th,natural isotopic abundance uranium (234U,235U, and238U), forgross alpha, and90Sr/90Y, and137Cs/137mBa for gross beta.Results
30、 are reported in activity units equivalent along with thereference radionuclide (for example, Bq/L gross alpha equiv.241Am).4.2 If the measurement quality objectives do not require alow detection limit, an aliquant of the sample may be mixeddirectly with a suitable liquid scintillation cocktail for
31、analysis.5. Significance and Use5.1 This test method is intended for the measurement ofgross alpha- and beta-activity concentrations in the analyses ofenvironmental and drinking waters. For samples submitted tosatisfy regulatory or permit requirements, the submitter shouldassure that this or any oth
32、er method used is acceptable to theregulator or permit issuer.5.2 This test method is also applicable to the direct analysisof gross alpha- and beta-activity concentrations in water whenlow detection limits are not required. Direct analysis providesa rapid method for determination of gross alpha- an
33、d beta-activity concentrations when low detection limits are notrequired.5.3 This test method is not capable of discriminating amongalpha emitting radionuclides or among beta emitting radionu-clides. Those intending to identify and quantify specific radio-nuclides should use test methods specific to
34、 the radionuclidesof interest.5.4 This test method may not be cited as a method for thedetermination of gross alpha- or beta-activity concentrations in7Available from International Organization for Standardization (ISO), 1 rue deVaremb, Case postale 56, CH-1211, Geneva 20, Switzerland, http:/www.iso
35、.ch.D7283 132a solid/soil matrix or the acid digestate of the same. The use ofthis test method for such applications brings the potential forserious bias and incomparability of results dependent on themanner of sample preparation or treatment, or both.6. Interferences6.1 The counting efficiencies an
36、d spillover for both thealpha and beta components are dependent on the energy of thealpha- or beta-emitter chosen to determine the calibrationcoefficient. Biases may occur if the energies of the alpha- orbeta-particle emitting nuclides in the test sample differs sig-nificantly from those used to det
37、ermine the respective countingefficiencies. Best results are obtained when the radionuclidecomposition of the sample is known and the calibrationradionuclide is selected to match as closely as possible theenergy of the sample radionuclide.6.2 The use of137Cs/137mBa as a calibration standard forsampl
38、es containing radionuclides other than137Cs may intro-duce a low bias in the analytical results unless there is acorrection for conversion electron emissions. The conversionelectrons from the137mBa progeny are detected by liquidscintillation yielding greater than 100 % detection efficiencyfor the137
39、Cs/137mBa calibration standard.6.3 When using uranium as a calibration standard theisotopic abundance of each of the isotopes (234U,235U,and238U) must be known to accurately determine the standardactivity concentration. Many uranium standards used for massmeasurements are depleted uranium. Natural i
40、sotopic abun-dance uranium and depleted uranium standards contain short-lived decay progeny (234Th,234mPa) which interfere with thespillover calibration unless they are removed immediately priorto calibration.6.4 Radon is a noble gas, and therefore easily emanatesfrom most matrices. If the radon pro
41、geny of the uranium(222Rn), thorium (220Rn), and actinium (219Rn) series emanatefrom the sample test source prior to counting, radioactiveequilibrium is disrupted. EPA 900.0 recognizes this disruptionby suggesting a delay of 72 h before the prepared sample iscounted for gross alpha. Other published
42、methods such asStandard Methods 7110C provide for a shorter delay of 3 h.Thus the activity of samples containing226Ra will increasesignificantly with time during the first several weeks afterpreparation. This delay will result in overestimation of theactivity of samples relative to their true226Ra c
43、oncentration.This test method advises that any such delay period used by thelaboratory be based on the measurement quality objectivesinherent in the intended data use (see 11.7).6.5 Radionuclides may be present in the sample in disequi-librium with their parent radionuclides. Many factors, includ-in
44、g differential solubility of radionuclides from the matrix inwhich the parent radionuclide occurs can cause this disequi-librium. Where these radionuclides have a half-life on the orderof a few days or shorter, the time elapsed between samplingand the beginning of sample counting will tend to bias t
45、he finalresult low. In those cases the measurement quality objectivesinherent in the intended data may dictate the maximum timebetween sample collection and the beginning of sample count-ing. The laboratory should be aware of such requirements andbe prepared to comply with them.6.6 Radionuclides inc
46、orporated in volatile compounds arelost during the conduct of this test method. These includetritium in HTO or14C in the carbon dioxide formed during theaddition of acid. The pertechnetate ion (TcO42) is an exampleof a radionuclide which may be lost through semi-volatility.The Measurement Quality Ob
47、jectives should address the po-tential loss of such radionuclides and provide direction for theirquantification by specific methods.6.7 When counting gross alpha- and beta-activity by a liquidscintillation counter using alpha/beta discrimination, somepulses resulting from alpha particles are misclas
48、sified as betaparticles and some pulses resulting from beta particles aremisclassified as alpha particles. The “spillover” characteristicsare determined during the calibration of the specific instrumentbeing used.6.8 Quenching of the photon output in the liquid scintilla-tion cocktail reduces detect
49、ion efficiency and introduces addi-tional uncertainty in spillover corrections. Quenching is causedby molecular species in the sample and cocktail mixture thatreduce the intermolecular transfer of energy or absorb emittedvisible and UV photons prior to detection. This test methoddescribes the use of an external standard source to compensatefor the effects of quenching.6.9 The presence of solid particles in the scintillationcocktail may lead to erroneous results. This test methodrequires complete dissolution of the sample prior to addition ofthe scintillat
