ASTM E1255-1996(2002) Standard Practice for Radioscopy《射线检查标准实施规范》.pdf

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1、Designation: E 1255 96 (Reapproved 2002)Standard Practice forRadioscopy1This standard is issued under the fixed designation E 1255; 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 (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice2provides application details for radio-scopic examination using penetrating radiation. This includesdynamic radioscopy and for the purposes of

3、 this practice,radioscopy where there is no motion of the object duringexposure (referred to as static radioscopic imaging). Since thetechniques involved and the applications for radioscopic ex-amination are diverse, this practice is not intended to belimiting or restrictive, but rather to address t

4、he general appli-cations of the technology and thereby facilitate its use. Referto Guides E 94 and E 1000, Terminology E 1316, PracticeE 747, Practice E 1025, and Fed. Std. Nos. 21 CFR 1020.40and 29 CFR 1910.96 for a list of documents that provideadditional information and guidance.1.2 The general p

5、rinciples discussed in this practice applybroadly to penetrating radiation radioscopic systems. However,this document is written specifically for use with X-ray andgamma-ray systems. Other radioscopic systems, such as thoseemploying neutrons, will involve equipment and applicationdetails unique to s

6、uch systems.1.3 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. Fo

7、r specific safetystatements, see Section 8 and Fed. Std. Nos. 21 CFR 1020.40and 29 CFR 1910.96.2. Referenced Documents2.1 ASTM Standards:E 94 Guide for Radiographic Examination3E 747 Practice for Design, Manufacture and MaterialGrouping Classification of Wire Image Quality Indicators(IQI) Used for R

8、adiology3E 1000 Guide for Radioscopy3E 1025 Practice for Design, Manufacture, and MaterialGrouping Classification of Hole-Type Image Quality Indi-cators (IQI) Used for Radiology3E 1316 Terminology for Nondestructive Examinations32.2 ASNT Standard:SNT-TC-1A Recommended Practice for Personnel Qualifi-

9、cation and Certification in Nondestructive Testing4ANSI/ASNT CP-189 Standard for Qualification and Certi-fication of Nondestructive Testing Personnel42.3 Federal Standards:21 CFR 1020.40 Safety Requirements of Cabinet X-RaySystems529 CFR 1910.96 Ionizing Radiation52.4 National Council on Radiation P

10、rotection and Mea-surement (NCRP) Standard:NCRP 49 Structural Shielding Design and Evaluation forMedical Use of X Rays and Gamma Rays of Energies Upto 10 MeV63. Summary of Practice3.1 Manual evaluation as well as computer-aided automatedradioscopic examination systems are used in a wide variety ofpe

11、netrating radiation examination applications. A simplemanual evaluation radioscopic examination system might con-sist of a radiation source and a directly viewed fluorescentscreen, suitably enclosed in a radiation protective enclosure. Atthe other extreme, a complex automated radioscopic examina-tio

12、n system might consist of an X-ray source, a roboticexamination part manipulator, a radiation protective enclosure,an electronic image detection system, a closed circuit televi-sion image transmission system, a digital image processor, avideo display, and a digital image archiving system. All system

13、components are supervised by the host computer, whichincorporates the software necessary to not only operate thesystem components, but to make accept/reject decisions aswell. Systems having a wide range of capabilities between1This practice is under the jurisdiction of ASTM Committee E07 on Nonde-st

14、ructive Testing and is the direct responsibility of Subcommittee E07.01 onRadiology (X and Gamma) Method.Current edition approved March 10, 1996. Published May 1996. Originallypublished as E 1255 88. Last previous edition E 1255 92b.2For ASME Boiler and Pressure Vessel Code applications see related

15、PracticeSE-1255 in Section II of that code.3Annual Book of ASTM Standards, Vol 03.03.4Available from the American Society for Nondestructive Testing, P.O. Box28518, 1711 Arlingate Lane, Columbus, OH 43228-0518.5Available from DODSSP, Bldg. 4, Section D, 700 Robbins Ave., Philadelphia,PA 19111-5098.6

16、Available from NCRP Publications, 7010 Woodmont Ave., Suite 1016, Be-thesda, MD 20814.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.these extremes can be assembled using available components.Guide E 1000 lists many different system

17、 configurations.3.2 This practice provides details for applying radioscopicexamination techniques, however, supplemental requirementsare necessary to address areas that are application and perfor-mance specific. Annex A1 and Annex A2 provide the detailedsupplemental requirements for government contr

18、acts (AnnexA1) and nongovernment contracts (Annex A2).4. Significance and Use4.1 As with conventional radiography, radioscopic exami-nation is broadly applicable to any material or examinationobject through which a beam of penetrating radiation may bepassed and detected including metals, plastics, c

19、eramics, com-posite, and other nonmetallic materials. In addition to thebenefits normally associated with radiography, radioscopicexamination may be either a dynamic, filmless techniqueallowing the examination part to be manipulated and imagingparameters optimized while the object is undergoing exam

20、ina-tion, or a static, filmless technique wherein the examinationpart is stationary with respect to the X-ray beam. Recenttechnology advances in the area of projection imaging, detec-tors, and digital image processing provide acceptable sensitiv-ity for a wide range of applications.5. Equipment and

21、Procedure5.1 System ConfigurationMany different radioscopic ex-amination systems configurations are possible, and it is impor-tant to understand the advantages and limitations of each. It isimportant that the optimum radioscopic examination system beselected for each examination requirement through

22、a carefulanalysis of the benefits and limitations of the available systemcomponents and the chosen system configuration. The provideras well as the user of the radioscopic examination servicesshould be fully aware of the capabilities and limitations of theradioscopic examination system that is propo

23、sed for examina-tion of the object. The provider and the user of radioscopicexamination services shall agree upon the system configurationto be used for each radioscopic examination application underconsideration, and how its performance is to be evaluated.5.1.1 The minimum radioscopic examination s

24、ystem con-figuration will include an appropriate source of penetratingradiation, a means for positioning the examination objectwithin the radiation beam, in the case of dynamic radioscopy,and a detection system. The system may be as simple as adirectly viewed fluorescent screen with suitable radiati

25、onshielding for personnel protection that meets applicable radia-tion safety codes.5.1.2 A more complex system might include the followingcomponents:5.1.2.1 A microfocus X-ray system to facilitate high-resolution projection imaging,5.1.2.2 A multiple axis examination part manipulation sys-tem to pro

26、vide dynamic, full volumetric examination partmanipulation under operator joystick or automated programcontrol, for dynamic radioscopy,5.1.2.3 An electronic imaging system to display a bright,two-dimensional gray-scale image of the examination part atthe operators control console,5.1.2.4 A digital i

27、mage processing system to perform imageenhancement and image evaluation functions,5.1.2.5 An archival quality image recording system, and5.1.2.6 A radiation protective enclosure with appropriatesafety interlocks and a radiation warning system.5.1.3 Whether a simple or a complex system is used, thesy

28、stem components and configuration utilized to achieve theprescribed examination results must be carefully selected.5.2 Practice:5.2.1 The purchaser and supplier for radioscopic examina-tion services shall mutually agree upon a written procedureusing the applicable annex of supplemental requirements

29、andalso consider the following general requirements.5.2.1.1 Equipment QualificationsA listing of the systemfeatures that must be qualified to ensure that the system iscapable of performing the desired radioscopic examinationtask.5.2.1.2 Examination Object Scan Plan for DynamicRadioscopyA listing of

30、object orientations, ranges of mo-tions, and manipulation speeds through which the object mustbe manipulated to ensure satisfactory examination.5.2.1.3 Radioscopic ParametersA listing of all the radia-tion source-related variables that can affect the examinationoutcome for the selected system config

31、uration such as: sourceenergy, intensity, focal spot size, range of source to objectdistances, range of object to image plane distances, and sourceto image plane distances.5.2.1.4 Image Processing ParametersA listing of all theimage processing variables necessary to enhance fine detaildetectability

32、in the object and to achieve the required sensitiv-ity level. These would include, but are not limited to, tech-niques such as noise reduction, contrast enhancement, andspatial filtering. Great care should be exercised in the selectionof directional image processing parameters such as spatialfilteri

33、ng, which may emphasize features in certain orientationsand suppress them in others. The listing should indicate themeans for qualifying image processing parameters.5.2.1.5 Image Display ParametersA listing of the tech-niques and the intervals at which they are to be applied forstandardizing the vid

34、eo image display as to brightness, con-trast, focus, and linearity.5.2.1.6 Accept-Reject CriteriaA listing of the expectedkinds of object imperfections and the rejection level for each.5.2.1.7 Performance EvaluationA listing of the qualifica-tion tests and the intervals at which they are to be appli

35、ed toensure that the radioscopic examination system is suitable forits intended purpose.5.2.1.8 Image Archiving RequirementsA listing of therequirements, if any, for preserving a historical record of theexamination results. The listing may include examinationimages along with written or electronical

36、ly recorded alphanu-meric or audio narrative information, or both, sufficient toallow subsequent reevaluation or repetition of the radioscopicexamination.5.2.1.9 Operator QualificationsNondestructive testing(NDT) personnel shall be qualified in accordance with anationally recognized NDT personnel qu

37、alification practice orE 1255 96 (2002)2a standard such as ANSI/ASNT-CP-189, SNT-TC, MIL STD-410, or a similar document, to the level appropriate for theperformance of the listed radioscopic examination.6. Radioscopic Examination System PerformanceConsiderations and Measurement6.1 Factors Affecting

38、System PerformanceTotal radio-scopic examination system performance is determined by thecombined performance of the system components that includesthe radiation source, manipulation system (for dynamic radios-copy), detection system, information processing system, imagedisplay, automatic evaluation

39、system, and examination recordarchiving system.6.1.1 Radiation SourcesWhile the radioscopic examina-tion systems may utilize either radioisotope or X-ray sources,X-radiation is used for most radioscopic examination applica-tions. This is due to the energy spectrum of the X-radiation thatcontains a b

40、lend of contrast enhancing longer wavelengths, aswell as the more penetrating, shorter wavelengths. X-radiationis adjustable in energy and intensity to meet the radioscopicexamination test requirements, and has the added safety featureof discontinued radiation production when switched off. Aradioiso

41、tope source has the advantages of small physical size,portability, simplicity, and uniformity of output.6.1.1.1 X-ray machines produce a more intense X-ray beamemanating from a smaller focal spot than do radioisotopesources. X-ray focal spot sizes range from a few millimetresdown to a few micrometre

42、s. Reducing the source size reducesgeometric unsharpness, thereby enhancing detail sensitivity.X-ray sources may offer multiple or variable focal spot sizes.Smaller focal spots produce higher resolution and providereduced X-ray beam intensity, while larger focal spots providehigher X-ray intensity a

43、nd produce lower resolution. Microfo-cus X-ray tubes are available with focal spots that may beadjusted to as small as a few micrometres in diameter, whilestill producing an X-ray beam of sufficient intensity so as to beuseful for the radioscopic examination of finely detailedobjects.6.1.1.2 Convent

44、ional focal spots of 1.0 mm and larger areuseful at low geometric magnification values close to 13.Fractional focal spots ranging from 0.4 mm up to 1.0 mm areuseful at geometric magnifications of up to approximately 23.Minifocus spots in the range from 0.1 mm up to 0.4 mm areuseful at geometric magn

45、ifications up to about 63. Greatermagnifications suggest the use of a microfocus spot size of lessthan 0.1 mm in order to minimize the effects of geometricunsharpness. Microfocus X-ray tubes are capable of focal spotsizes of less than 10 micrometres (108metres) and are usefulfor geometric magnificat

46、ions of more than 1003.6.1.2 Manipulation System for Dynamic RadioscopyTheexamination part manipulation system has the function ofholding the examination object and providing the necessarydegrees of freedom, ranges of motion, and speeds of travel toposition the object areas of interest in the radiat

47、ion beam insuch a way so as to maximize the radioscopic examinationsystems response. In some applications it may be desirable tomanipulate the radiation source and detection system insteadof, or in addition to, the object. The manipulation system mustbe capable of smooth well-controlled motion, espe

48、cially so forhigh-magnification microfocus techniques, to take full advan-tage of the dynamic aspects of the radioscopic examination.6.1.3 Detection SystemThe detection system is a keyelement. It has the function of converting the radiation inputsignal containing part information, into a correspondi

49、ng opticalor electronic output signal while preserving the maximumamount of object information. The detector may be of one-dimensional design, providing examination part informationone line at a time, or may be a two-dimensional area detectorproviding an area field of view.6.1.4 Information Processing of System:6.1.4.1 The function of the information processing system isto take the output of the detection system and present a usefulimage for display and operator interpretation, or for automaticevaluation. The information processing system may take manydifferent form