ASTM_D_1943_-_05_2012.pdf

Designation:D194305(Reapproved 2012)Standard 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 parentheses 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 Department of Defense.1.Scope1.1 This test method covers the measurement of alphaparticle activity of water.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 analysis.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.General information on radioactivity and measurement ofradiation has been published2and summarized in PracticeD3648.1.3 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 safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards: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 Closed ConduitsD3648 Practices for the Measurement of Radioactivity3.Terminology3.1 DefinitionsFor definitions of terms used in this testmethod,refer to Terminology D1129.For terms not defined inthis test method or in Terminology D1129,reference may bemade to other published glossaries.44.Summary of Test Method4.1 The test sample is reduced 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 proportional 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 isaccelerated 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 state by re-emitting energyin the form of light quanta.A suitable light-sensitive device,usually a multiplier phototube,transforms the resulting flashesof light into voltage impulses.By use of suitable electronicapparatus,the pulse is amplified to a voltage sufficient foroperation of the counting scaler.The number of pulses per unittime is related to the disintegration rate of the test sample.Theefficiency of the system can be determined by use of a suitablealpha standard having equivalent residual plated solids.5.Significance and Use5.1 This test method was developed for the purpose ofmeasuring gross alpha radioactivity in water.It is used for the1This 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 June 1,2012.Published August 2012.Originallyapproved in 1996.Last previous edition approved in 2005 as D1943 05.DOI:10.1520/D1943-05R12.2Friedlander,G.,et al.,Nuclear and Radiochemistry,3rd Ed.,John Wiley andSons,Inc.,New York,NY,1981.Price,W.J.,Nuclear Radiation Detection,2nd Ed.,McGraw-Hill Book Co.,Inc.,New York,NY,1964.Lapp,R.E.,and Andrews,H.L.,Nuclear Radiation Physics,4th Ed.,Prentice-Hall Inc.,New York,NY,1972.Overman,R.T.,and Clark,H.M.,Radioisotope Techniques,McGraw-Hill BookCo.,Inc.,New York,NY,1960.3For 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.4American National Standard Glossary of Terms in Nuclear Science andTechnology(ANSI N1.1)available from the American National Standards Institute,1430 Broadway,New York,NY 10018.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United