1、Designation:D194320Standard Test Method forAlpha Particle Radioactivity of Water1This standard is issued under the fixed designation D1943;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parenthe
2、ses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S.Department of Defense.1.Scope1.1 This test method covers the measurement of alphaparticle activity of wat
3、er.It is applicable to nuclides that emitalpha particles with energies above 3.9 MeV and at activitylevels above 0.02 Bq/mL(540 pCi/L)of radioactive homoge-neous water.This test method is not applicable to samplescontaining alpha-emitting radionuclides that are volatile underconditions of the analys
4、is.1.2 This test method can be used for either absolute orrelative determinations.In tracer work,the results may beexpressed by comparison with a standard that is defined to be100%.For radioassay,data may be expressed in terms of alphadisintegration rates after calibration with a suitable standard.G
5、eneral information on radioactivity and measurement ofradiation has been published in Refs(1-3)2and summarized inPractices D3648.1.3 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.4 This standard does not purport to address al
6、l of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.5 This international standard was developed in acc
7、or-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM S
8、tandards:3D1129 Terminology Relating to WaterD1193 Specification for Reagent WaterD2777 Practice for Determination of Precision and Bias ofApplicable Test Methods of Committee D19 on WaterD3370 Practices for Sampling Water from Flowing ProcessStreamsD3648 Practices for the Measurement of Radioactivi
9、tyD4448 Guide for Sampling Ground-Water Monitoring WellsD6001 Guide for Direct-Push Groundwater Sampling forEnvironmental Site CharacterizationD7282 Practice for Set-up,Calibration,and Quality Controlof Instruments Used for Radioactivity MeasurementsD7902 Terminology for Radiochemical Analyses3.Term
10、inology3.1 Definitions:3.1.1 For definitions of terms used in this standard,refer toTerminologies D1129 and D7902.3.1.2 For terms not defined in this standard,TerminologyD1129,or Terminology D7902,reference may be made toother published glossaries.4.Summary of Test Method4.1 The test sample is reduc
11、ed by evaporation or a suitablechemical method to the minimum weight of material havingmeasurable alpha activity.Alpha radioactivity is measured byan instrument composed of a detecting device,amplifier,powersupply,and scalerthe most widely used being proportionaland scintillation counters.In the pro
12、portional counter,whichmay be of the windowless or thin window type,alpha particlesentering the sensitive region of the detector produce ionizationof the counting gas.The negative ion of the original ion pair is1This test method is under the jurisdiction of ASTM Committee D19 on Waterand is the dire
13、ct responsibility of Subcommittee D19.04 on Methods of Radiochemi-cal Analysis.Current edition approved Oct.15,2020.Published November 2020.Originallyapproved in 1996.Last previous edition approved in 2012 as D1943 05(2012).DOI:10.1520/D1943-20.2The boldface numbers in parentheses refer to a list of
14、 references at the end ofthis standard.3For referenced ASTM standards,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.Copyright ASTM Internationa
15、l,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis 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 Re
16、commendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.1accelerated towards the anode,producing additional ionizationof the counting gas and developing a voltage pulse at theanode.In the scintillation detector,alpha particles interact withthe material of the phosphor,transferring some of their energyto electrons.These electrons subsequently lose part of theirenergy by excitation rather than ionization of atoms,and theexcited atoms revert to the ground stat