ASTM_E_1172_-_87_2011.pdf

Designation:E117287(Reapproved 2011)Standard Practice forDescribing and Specifying a Wavelength-Dispersive X-RaySpectrometer1This standard is issued under the fixed designation E1172;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 practice covers the components of a wavelength-dispersive X-ray spectrometer that are basic to its operationand to the quality of its performance.It is not the intent of thispractice to specify component tolerances or performancecriteria,as these are unique for each instrument.The documentdoes,however,attempt to identify which of these are criticaland thus which should be specified.1.2 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.Specific safetyhazard statements are given in 5.3.1.2 and 5.3.2.4,and inSection 7.1.3 There are several books and publications from theNational Institute of Standards and Technology2and the U.S.Government Printing Office3,4which deal with the subject ofX-ray safety.Refer also to Practice E416.52.Referenced Documents2.1 ASTM Standards:5E135 Terminology Relating to Analytical Chemistry forMetals,Ores,and Related MaterialsE416 Practice for Planning and Safe Operation of a Spec-trochemical Laboratory(Withdrawn 2005)6E876 Practice for Use of Statistics in the Evaluation ofSpectrometric Data(Withdrawn 2003)63.Terminology3.1 For terminology relating to X-ray spectrometry,refer toTerminology E135.4.Significance and Use4.1 This practice describes the essential components of awavelength-dispersive X-ray spectrometer.This description ispresented so that the user or potential user may gain a cursoryunderstanding of the structure of an X-ray spectrometer sys-tem.It also provides a means for comparing and evaluatingdifferent systems as well as understanding the capabilities andlimitations of each instrument.5.Description of Equipment5.1 Types of SpectrometersX-ray spectrometers can beclassified as sequential,simultaneous,or a combination ofthese two(hybrid).5.1.1 Sequential SpectrometersThe sequential spectrom-eter disperses and detects secondary X rays by means of anadjustable monochromator called a goniometer.In flat-crystalinstruments,secondary X rays are emitted from the specimenand nonparallel X rays are eliminated by means of a Soller slit(collimator).The parallel beam of X rays strikes a flatanalyzing crystal which disperses the X rays according to theirwavelengths.The dispersed X rays are then measured bysuitable detectors.Adjusting the goniometer varies the anglebetween the specimen,crystal,and detector,permitting themeasurement of different wavelengths and therefore differentelements.Sequential instruments containing curved-crystaloptics are less common.This design substitutes curved for flatcrystals and entrance and exit slits for collimators.5.1.2 Simultaneous SpectrometersSimultaneous spec-trometers use separate monochromators to measure each ele-ment.These instruments are for the most part of fixedconfiguration,although some simultaneous instruments have a1This practice is under the jurisdiction of ASTM Committee E01 on AnalyticalChemistry for Metals,Ores,and Related Materials and is the direct responsibility ofSubcommittee E01.20 on Fundamental Practices.Current edition approved Nov.15,2011.Published June 2012.Originallyapproved in 1987.Last previous edition approved in 2003 as E1172 87(2003).DOI:10.1520/E1172-87R11.2NBS Handbook,X-Ray Protection,HB76,and NBS Handbook 111,ANSIN43.2-1971,available from National Institute of Standards and Technology,Gaithersburg,MD 20899.3Radiation Safety Recommendations for X-Ray Diffraction and SpectrographicEquipment,No.MORP 68-14,1968,available from U.S.Department of Health,Education,and Welfare,Rockville,MD 20850.4U.S.Government Handbook 93,Safety Standards for Non-Medical X-Ray andSealed Gamma-Ray Sources,Part 1,General,Superintendent of Documents,available from U.S.Government Printing Office,Washington,DC 22025.5For 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.6The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 scanning channel with limited function.A typical monochro-mator consists of an entrance slit,a curved(focusing)analyz-ing crystal,an exit slit,and a suitable detector.Secondary Xrays pass through the entr