ASTM_E_1931_-_16.pdf

Designation:E193116Standard Guide forNon-computed X-Ray Compton Scatter Tomography1This standard is issued under the fixed designation E1931;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 PurposeThis guide covers a tutorial introduction tofamiliarize the reader with the operational capabilities andlimitations inherent in a single non-computed X-ray ComptonScatter Tomography(CST).Also included is a brief descriptionof the physics and typical hardware configuration for CST.Thissingle technique is still used for a small number of inspections.This is not meant as comprehensive guide covering the varietyof Compton scattering techniques that are now used fornon-destructive testing and security screen screening.1.2 AdvantagesX-ray Compton Scatter Tomography(CST)is a radiologic nondestructive examination method withseveral advantages that include:1.2.1 The ability to perform X-ray examination withoutaccess to the opposite side of the examination object;1.2.2 The X-ray beam need not completely penetrate theexamination object allowing thick objects to be partiallyexamined.Thick examination objects become part of theradiation shielding thereby reducing the radiation hazard;1.2.3 The ability to examine and image object subsurfacefeatures with minimal influence from surface features;1.2.4 The ability to obtain high-contrast images from lowsubject contrast materials that normally produce low-contrastimages when using traditional transmitted beam X-ray imagingmethods;and1.2.5 The ability to obtain depth information of objectfeatures thereby providing a three-dimensional examination.The ability to obtain depth information presupposes the use ofa highly collimated detector system having a narrow angle ofacceptance.1.3 ApplicationsThis guide does not specify which exami-nation objects are suitable,or unsuitable,for CST.As withmost nondestructive examination techniques,CST is highlyapplication specific thereby requiring the suitability of themethod to be first demonstrated in the application laboratory.This guide does not provide guidance in the standardizedpractice or application of CST techniques.No guidance isprovided concerning the acceptance or rejection of examina-tion objects examined with CST.1.4 LimitationsAs with all nondestructive examinationmethods,CST has limitations and is complementary to otherNDE methods.Chief among the limitations is the difficulty inperforming CST on thick sections of high-Z materials.CST isbest applied to thinner sections of lower Z materials.Thefollowing provides a general idea of the range of CSTapplicability when using a 160 keV constant potential X-raysource:MaterialPractical Thickness RangeSteelUp to about 3 mm(18in.)AluminumUp to about 25 mm(1 in.)Aerospace compositesUp to about 50 mm(2 in.)Polyurethane FoamUp to about 300 mm(12 in.)The limitations of the technique must also consider therequired X,Y,and Z axis resolutions,the speed of imageformation,image quality and the difference in the X-rayscattering characteristics of the parent material and the internalfeatures that are to be imaged.1.5 The values stated in both inch-pound and SI units are tobe regarded separately as the standard.The values given inparentheses are for information only.1.6 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 to determine theapplicability of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2E747 Practice for Design,Manufacture and Material Group-ing Classification of Wire Image Quality Indicators(IQI)Used for RadiologyE1025 Practice for Design,Manufacture,and MaterialGrouping Classification of Hole-Type Image Quality In-dicators(IQI)Used for RadiologyE1255 Practice for Radioscopy1This guide is under the jurisdiction of ASTM Committee E07 on Nondestruc-tive Testing and is the direct responsibility of E07.01 on Radiology(X and Gamma)Method.Current edition approved June 1,2016.Published June 2016.Originallyapproved in 1997.Last previous edition approved in 2009 as E1931 09.DOI:10.1520/E1931-16.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 E1316 Terminology for Nondestructive ExaminationsE1441 Guide for Computed Tomography(CT)ImagingE1453 Guide for Storage of Magnetic Tape Media thatContains Analog or Digital Radioscopic DataE1475 Guide for Data Fields for Computerized Transf