ASTM_C_1255_-_11.pdf

Designation:C125511Standard Test Method forAnalysis of Uranium and Thorium in Soils by EnergyDispersive X-Ray Fluorescence Spectroscopy1This standard is issued under the fixed designation C1255;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 This test method covers the energy dispersive X-rayfluorescence(EDXRF)spectrochemical analysis of trace levelsof uranium and thorium in soils.Any sample matrix that differsfrom the general ground soil composition used for calibration(that is,fertilizer or a sample of mostly rock)would have to becalibrated separately to determine the effect of the differentmatrix composition.1.2 The analysis is performed after an initial drying andgrinding of the sample,and the results are reported on a drybasis.The sample preparation technique used incorporates intothe sample any rocks and organic material present in the soil.This test method of sample preparation differs from othertechniques that involve tumbling and sieving the sample.1.3 Linear calibration is performed over a concentrationrange from 20 to 1000 g per gram for uranium and thorium.1.4 The values stated in SI units are to be regarded as thestandard.The inch-pound units in parentheses are for informa-tion only.1.5 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:2C859 Terminology Relating to Nuclear MaterialsC998 Practice for Sampling Surface Soil for RadionuclidesD420 Guide to Site Characterization for Engineering Designand Construction Purposes(Withdrawn 2011)3D1452 Practice for Soil Exploration and Sampling by AugerBoringsD1586 Test Method for Penetration Test(SPT)and Split-Barrel Sampling of SoilsD1587 Practice for Thin-Walled Tube Sampling of Soils forGeotechnical PurposesD2113 Practice for Rock Core Drilling and Sampling ofRock for Site InvestigationD3550 Practice for Thick Wall,Ring-Lined,Split Barrel,Drive Sampling of SoilsD4697 Guide for Maintaining Test Methods in the UsersLaboratory(Withdrawn 2009)3E135 Terminology Relating to Analytical Chemistry forMetals,Ores,and Related MaterialsE305 Practice for Establishing and Controlling AtomicEmission Spectrochemical Analytical CurvesE456 Terminology Relating to Quality and StatisticsE876 Practice for Use of Statistics in the Evaluation ofSpectrometric Data(Withdrawn 2003)3E882 Guide for Accountability and Quality Control in theChemical Analysis Laboratory2.2 Other Document:ANSI/HPS N43.2-2001 Radiation Safety for X-ray Diffrac-tion and X-ray Fluorescence Equipment43.Terminology3.1 Definitions:3.1.1 For definitions of terms relating to the nuclear fuelcycle,refer to Terminology C859.3.1.2 For definitions of terms relating to analytical atomicspectroscopy,refer to Terminology E135.3.1.3 For definitions of terms relating to statistics refer toTerminology E456.3.2 Definitions of Terms Specific to This Standard:3.2.1 escape peaka peak generated by an X-ray havingenergy greater than 1.84 keV(the energy of the k-alphaabsorption edge for silicon)that enters the detector and causes1This test method is under the jurisdiction ofASTM Committee C26 on NuclearFuel Cycle and is the direct responsibility of Subcommittee C26.05 on Methods ofTest.Current edition approved June 1,2011.Published June 2011.Originallyapproved in 1993.Last previous edition approved in 2005 as C1255 93(2005).DOI:10.1520/C1255-11.2For 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.3The last approved version of this historical standard is referenced onwww.astm.org.4Available from American National Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036,http:/www.ansi.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 the silicon detector crystal to fluoresce.If the silicon X-rayescapes the detector,carrying with it the energy of the siliconk-alpha X-ray,2.79 E-16 Joules J(1.74 keV),the energymeasured for the detected X-ray will be less than the actualX-ray energy by exactly 2.79 E-16 J(1.74 keV).Therefore,ascounts accumulate for any major X-ray peak,an escape peakcan be expected to appear at an energy of 2.79 E-16 J(1.74keV)below the major peak.Escape peaks can be calculatedand removed from the spectrum by most instrumentationsoftware.3.2.2 flux monitor(FM)valuethe detected X-ray intensitywithin a specified spectral range from a metallic stand