ASTM_C_1673_-_10a_2018.pdf

Designation:C167310a(Reapproved 2018)Standard Terminology ofC26.10 Nondestructive Assay Methods1This standard is issued under the fixed designation C1673;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.1.Scope1.1 The terminology defined in this document is associatedwith nondestructive assay of nuclear material.1.2 All of the definitions are associated with measurementtechniques that measure nuclear emissions(that is,neutrons,gamma-rays,or heat)directly or indirectly.1.3 Definitions are relevant to any standards and guideswritten by subcommittee C26.10.1.4 This international standard was developed in accor-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 Standards:2E456 Terminology Relating to Quality and Statistics2.2 DOE Orders:3DOE Order 435.1 Low-level Waste RequirementsDOE Order 5820.2 Radioactive Waste Management3.Terminology(alpha,n)reaction,na reaction that occurs when energeticalpha particles collide with low atomic number nucleiresulting in the emission of a neutron.240Pu-effective mass,240Pueff,nthe mass of240Pu thatwould produce the same coincident neutron response in theinstrument as the assay item.DISCUSSIONIt is a function of the quantity of even mass isotopes ofplutonium in the assay item and fundamental nuclear constants,sometimes referred to as effective240Pu mass.absorber foils,nfoils,usually of copper,tin,cadmium,orlead,used to attenuate the gamma flux reaching a detector.DISCUSSIONAbsorber foils are used to reduce the count rate,typically from intense low-energy X or gamma rays.accidentals,nthe detection of multiple neutron events withinthe gate width that are not produced from the same fission.DISCUSSIONAccidental events take their name from the fact that itis the accidental or random summing of neutrons,which are not timecorrelated with a common origin(fission or cosmic-ray burst),that giverise to the appearance of a signature like that from genuine correlatedevents.active assay,nassay based on the observation of radiation(s)induced by irradiation from an external source.alpha,nthe ratio of the uncorrelated neutron emission ratefrom(,n)reactions to the spontaneous neutron emissionrate from a non-multiplying item.aperture,nthe size of the opening in the collimator throughwhich the radiation of interest is intended to pass.assay,vto determine quantitatively the amount of one ormore nuclides of interest contained in an item.attenuation correction,ncorrection to the measured countrate for attenuation of radiation that provides an estimate ofthe unattenuated radiation emission rate of the radionuclidesbeing assayed.attenuation,nreduction of radiation flux due to the interac-tion of radiation with material between the source of theradiation and the detector.background,nextraneous signal superimposed on the signalof interest.Beers Law,nthe fraction of uncollided gamma rays trans-mitted through layers of equal thickness of an absorber is aconstant.benign matrix,nbulk material that has a negligible effect onthe result of the measured parameter.blank,na prepared item containing a matrix as similar aspractical to the items being measured that is free,to theextent possible,of the radionuclides of interest.DISCUSSIONThe most important matrix parameters are those thataffect the result of the measurement technique being used.1This terminology is under the jurisdiction ofASTM Committee C26 on NuclearFuel Cycle and is the direct responsibility of Subcommittee C26.10 on NonDestructive Assay.Current edition approved April 1,2018.Published May 2018.Originallyapproved in 2007.Last previous edition approved in 2010 as C1673 10a1.DOI:10.1520/C1673-10AR18.2For 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 Summary page onthe ASTM website.3Available from the U.S.Department of Energy(DOE),1000 IndependenceAve.,SW Washington,DC 20585.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 Organization Technical Barriers to Trade(TBT)Committee.1 calibration standard,nan item similar to the items to beassayed,for which the parameters of interest and all prop-erties to which the