1、Designation:D308420Standard Practice forAlpha-Particle Spectrometry of Water1This standard is issued under the fixed designation D3084;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
2、indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This practice covers the processes that are required toobtain well-resolved alpha-particle spectra from water samplesand discusses associated problems.This pract
3、ice is generallycombined with specific chemical separations,mountingtechniques,and counting instrumentation,as referenced.1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.3 This standard does not purport to address all of th
4、esafety 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.1.4 This international standard was developed in accor-danc
5、e 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 Standard
6、s:2C859 Terminology Relating to Nuclear MaterialsC1163 Practice for Mounting Actinides for Alpha Spectrom-etry Using Neodymium FluorideD1129 Terminology Relating to WaterD3648 Practices for the Measurement of RadioactivityD3865 Test Method for Plutonium in WaterD3972 Test Method for Isotopic Uranium
7、 in Water byRadiochemistryD7282 Practice for Set-up,Calibration,and Quality Controlof Instruments Used for Radioactivity MeasurementsD7902 Terminology for Radiochemical Analyses3.Terminology3.1 Definitions:3.1.1 For definitions of terms used in this standard,refer toTerminologies D1129,D7902,and C85
8、9.For terms not foundin these terminologies,reference may be made to otherpublished glossaries(1,2).34.Summary of Practice4.1 Alpha-particle spectrometry of radionuclides in water(also called alpha-particle pulse-height analysis)has beencarriedoutbyseveralmethodsinvolvingmagneticspectrometers,gas co
9、unters,scintillation spectrometers,nuclearemulsionplates,cloudchambers,absorptiontechniques,and solid-state counters.Gas counters,operatingeither as an ionization chamber or in the proportional region,have been widely used to identify and measure the relativeamounts of different alpha-emitters.Howev
10、er,more recently,the solid-state counter has become the predominant systembecause of its excellent resolution and compactness.Knoll(3)extensively discusses the characteristics of both detector types.4.2 Of the two gas-counting techniques,the pulsed ioniza-tion chamber is more widely used as it gives
11、 much betterresolution than does the other.This is because there is nospread arising from multiplication or from imperfection of thewire such as occurs with the proportional counter.4.3 The semiconductor detectors used for alpha-particlespectrometry are similar in principle to ionization chambers.Th
12、e ionization of the gas by-particles gives rise to electron-ion pairs,while in a semiconductor detector,electron-holepairs are produced.Subsequently,the liberated charges arecollected by an electric field.In general,silicon detectors areused for alpha-particle spectrometry.These detectors are n-type
13、base material upon which gold is evaporated or ions such asboron are implanted,making an electrical contact.A reversedbias is applied to the detector to reduce the leakage current andto create a depletion layer of free-charge carriers.This layer isthin and the leakage current is very low.Therefore,t
14、he slightinteractions of photons with the detector produce no signal.1This practice is under the jurisdiction of ASTM Committee D19 on Water andis the direct responsibility of Subcommittee D19.04 on Methods of RadiochemicalAnalysis.Current edition approved July 1,2020.Published July 2020.Originally
15、approvedin 1972.Last previous edition approved in 2012 as D3084 05(2012).DOI:10.1520/D3084-20.2For 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 Summ
16、ary page onthe ASTM website.3The boldface numbers in parentheses refer to a list of references at the end ofthis standard.Copyright ASTM International,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 Recommendations issued by the World Trade Organizatio
