1、Designation: E 1114 09Standard Test Method forDetermining the Size of Iridium-192 Industrial RadiographicSources1This standard is issued under the fixed designation E 1114; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year o
2、f 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 determination of the size ofan Iridium-192 radiographic source. The determination isbase
3、d upon measurement of the image of the Iridium metalsource in a projection radiograph of the source assembly andcomparison to the measurement of the image of a referencesample in the same radiograph.1.2 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard
4、. The values stated ineach system may not be exact equivalents; therefore, eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in non-conformancewith the standard.1.3 This standard does not purport to address all of thesafety concerns, if any, associa
5、ted 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:2E 999 Guide for Controlling the Quality of Industrial Ra-dio
6、graphic Film ProcessingE 1316 Terminology for Nondestructive ExaminationsE 1815 Test Method for Classification of Film Systems forIndustrial RadiographyE 2445 Practice for Qualification and Long-Term Stabilityof Computed Radiology SystemsE 2597 Practice for Manufacturing Characterization ofDigital D
7、etector Arrays2.2 Other International Standards:EN 12579 Industrial RadiographyRadiographic Methodfor the Determination of the Source Size for Radioiso-topes33. Terminology3.1 For definitions of terms relating to this test method, referto Terminology E 1316.4. Significance and Use4.1 One of the fact
8、ors affecting the quality of a radiographicimage is geometric unsharpness. The degree of geometricunsharpness is dependent upon the size of the source, thedistance between the source and the object to be radiographed,and the distance between the object to be radiographed and thefilm or digital detec
9、tor. This test method allows the user todetermine the size of the source and to use this result toestablish source to object and object to film or detectordistances appropriate for maintaining the desired degree ofgeometric unsharpness.NOTE 1The European standard CEN EN 12579 describes a simplifiedp
10、rocedure for measurement of source sizes of Ir-192, Co-60 and Se-75.The resulting source size of Ir-192 is comparable to the results obtained bythis test method.5. Apparatus5.1 Subject Iridium-192 Source, the source size of which isto be determined. The appropriate apparatus and equipment forthe saf
11、e storage, handling, and manipulation of the subjectsource, such as a radiographic exposure device (also referred toas a gamma ray projector or camera), remote control, sourceguide tube, and source stop are also required.5.2 Reference Sample (see Figs. 1-3)The referencesample shall be of material wh
12、ich is not radioactive. Therecommended material is Iridium. However, substitutes such asplatinum, tungsten or other material of similar radiopacity may1This test method is under the jurisdictioin of ASTM Committee E07 onNondestructive Testing and is the direct responsibility of Subcommittee E07.01 o
13、nRadiology (X and Gamma) Method.Current edition approved June 1, 2009. Published July 2009. Originally approvedin 1986. Last previous edition approved in 2003 as E 1114 03.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For An
14、nual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C
15、700, West Conshohocken, PA 19428-2959, United States.be used. The sample should be of the same geometric shape asthe subject source, should be approximately the same size asthe subject source, and should be positioned on or within ashim or envelope to simulate the source capsule wall. Theresulting r
16、adiographic contrast, with reference to adjacentbackground density of the image of the reference sample,should be approximately the same as that of the subject source.The actual dimensions of the reference sample should bedetermined to the nearest 0.025 mm (0.001 in.).5.3 X-ray Generator, capable of
17、 producing a radiationintensity (roentgen per hour at one metre) at least ten timesgreater than that produced by the subject source. Examples oftypical X-ray generator output requirements that satisfy thiscriterion are presented in Table 1.5.4 Film systemsOnly film systems having cognizantengineerin
18、g organization approval or meeting the system classrequirements of Test Method E 1815, for system classes I, II orSpecial, shall be used. Selection of film systems should bedetermined by such factors as the required radiographic qualitylevel, equipment capability, materials and so forth. The filmsys
19、tem selected shall be capable of demonstrating the requiredimage quality. No intensifying screens shall be used. Radio-graphic films shall be processed in accordance with GuideE 999.5.5 Image Measurement ApparatusThis apparatus is usedto measure the size of the image of the spot. The apparatusshall
20、be an optical comparator with built-in graticule with 0.1mm divisions or 0.001 in. divisions and magnification of 53 to103.5.6 Digital DetectorsDigital detectors, which are eitherimaging plates or digital detector arrays, may be used as filmreplacement. The digital detector shall possess a pixel pit
21、chwhich is at least 40 times smaller than the nominal source sizeto measure and a basic spatial resolution smaller than120 of thenominal source size. The basic spatial resolution shall bemeasured in accordance with the procedure of Practice E 2597for DDAs or Practice E 2445 for the imaging plate sca
22、nnersystem or taken from manufacturer statements. In the area offree beam a detector SNRD 100 shall be achieved. TheFIG. 1 Reference Sample in Standard Source EncapsulationFIG. 2 Alternate Reference Sample ArrangementFIG. 3 Alternate Reference Sample ArrangementTABLE 1 Examples of Typical X-ray Gene
23、rator OutputRequirements for Related Iridium192Source ActivitiesSubject Iridium192SourceRadiationTypical X-ray GeneratorOutput RequirementsActivity(Curie)Output(R/h at 1 m)Potential Current30 14.4 160 kV 5 mAor 200 kV 3 mA100 48.0 160 kV 10 mAor 250 kV 4 mA200 96.0 160 kV 20 mAor 250 kV 8 mAor 300 k
24、V 6 mAE1114092measurement procedure of the SNR shall be in accordance withthe procedure of Practice E 2597 for DDAs or Practice E 2445for the imaging plate scanner system.5.7 Evaluation of Digital ImagesDigital images shall beevaluated by an image processing software with contrast,brightness, profil
25、e and zoom function. The digital images shallbe magnified at the monitor to a degree that allows the imageviewing with at least one pixel of the image at one pixel of themonitor.6. Procedure6.1 Set up the exposure arrangement as shown in Figs. 4-7.Position the X-ray tube directly over the center of
26、the film ordigital detector. The film or detector plane must be normal tothe central ray of the X-ray beam. The X-ray spot should be0.90 m (36 in.) from the film or detector. Position the referencesample and apparatus used to locate the subject source (sourcestop) as close together as possible and d
27、irectly over the centerof the film or detector. The plane of the source stop andreference sample must be parallel to the film or detector andnormal to the central ray of the X-ray beam. The source stopand reference sample should be 0.15 m (6 in.) from the film ordetector. The source stop should be c
28、onnected to the radio-graphic exposure device by the shortest source guide tubepracticable in order to minimize fogging of the film or detectorduring source transit.6.2 Place identification markers to be imaged on the film ordetector to identify, as a minimum, the identification (serialnumber) of th
29、e subject source, the size of the reference sample,the identification of the organization performing the determi-nation, and the date of the determination. Care should be takento ensure that the images of the subject source and referencesample will not be superimposed on the image of the identifi-ca
30、tion markers.6.3 ExposureSelect the X-ray tube potential (kV), X-raytube current (mA) and exposure time such that the density inthe image of the envelope surrounding the reference sampledoes not exceed 3.0 and that the density difference between theimage of the reference sample and the image of the
31、envelopesurrounding the reference sample is at least 0.10. In digitalimages the linear grey value difference between the image ofthe reference sample and the image of the envelope surround-ing the reference sample shall be five times larger than theimage noise s(s = standard deviation of the grey va
32、luefluctuations in an area of homogeneous exposure, measured ina window of at least 20 by 55 pixels) in a homogeneousneighbor area.NOTE 2The actual parameters that will produce acceptable resultsmay vary between X-ray units, and trial exposures may be necessary.6.3.1 Energize the X-ray generator and
33、, at the same time,manipulate the subject source into the exposure position in thesource stop. It is important that this be performed as quickly aspossible to minimize fogging of the film or detector.6.3.2 At the conclusion of the exposure time, deenergize theX-ray generator and, at the same time, r
34、eturn the subject sourceto the proper shielded storage position.6.3.3 Process the film or read out the digital detector arrayor scan the imaging plate.7. Measurement of Source Dimensions7.1 View the film radiograph with sufficient light intensityfor adequate viewing. Using an optical comparator with
35、built-in graticule as described in 5.5, measure the lineardimensions of the image of the spot size of the subject sourceFIG. 4 Typical Exposure ArrangementFIG. 5 Typical Arrangement Using a Specially Designed GuideTubeFIG. 6 Typical Arrangement Using a Standard Guide Tube andSpecial Positioning Fixt
36、ureE1114093and the reference sample. Take measurements from the per-ceptible edges of the image. When performing the physicalmeasurements with the optical comparator, the actual measuredvalues shall be to the nearest graduation on the graticule scalebeing used.7.2 Read the digital image in a darkene
37、d room and use abright monitor with at least 250 cd/m2. Use the profile functionof the image processing software for size measurement indigital images after proper brightness and contrast adjustment.7.3 The source size for a given technique is the maximumprojected dimension of the source in the plan
38、e perpendicular toa line drawn from the source to the object being radiographed.Therefore, sufficient measurements of the image of the Iridiummust be made to determine the size of the source in anyorientation. Sections 7.4-7.7 serve as examples.7.4 Uniform Right Circular Cylinder (see Fig. 8)Determi
39、ne the source size of a uniform right circular cylindri-cal source by measuring the diameter, d, the height, h, and thediagonal, m, as illustrated in Fig. 8 and computing the actualdimensions as described in 8.1.7.5 Sphere (see Fig. 9)Determine the size of a sphericalsource by measuring the diameter
40、, d, as illustrated in Fig. 9 andcomputing the actual dimension as described in 8.1.7.6 Nonuniform Stack of Right Circular Cylinders (see Fig.10)Determine the size of a nonuniform stack of right circularcylindrical components of a source by measuring the intrinsicdiameter, d, the height, h, and the
41、effective maximum dimen-sion, m, as illustrated in Fig. 10 and computing the actualdimensions as described in 8.1.7.7 Separated Stack of Right Circular Cylinders (see Fig.11)Determine the size of a separated stack of right circularcylindrical components of a source by measuring the intrinsicdiameter
42、, d, the effective height, h, and the effective maximumdimension, m, as illustrated in Fig. 11 and computing the actualdimensions as described in 8.1.8. Calculation and Evaluation8.1 Measure the linear dimension of interest in the subjectsource image and measure the same linear dimension in therefer
43、ence sample image (that is, the diameter of each). Theactual dimension of the subject source is computed from thefollowing:FIG. 7 Typical Arrangement Using Reference Sample Positioning DeviceFIG. 8 Uniform Right Circular CylinderFIG. 9 SphereFIG. 10 Nonuniform Cylindrical StackFIG. 11 Separated Cyli
44、ndrical StackE1114094a 5 bc/dwhere:a = actual dimension of the subject source,b = actual dimension of the reference sample,c = measured dimension of the subject source image, andd = measured dimension of the reference sample image.9. Report9.1 A report of the size of an Iridium-192 source shouldindi
45、cate the model number and serial number of the source, thename of the organization making the determination, the datethe determination was made, a description of the shape of thesource (or an appropriate sketch), and the calculated actualdimensions. The actual radiograph should accompany thereport.1
46、0. Precision and Bias10.1 PrecisionIt is not possible to specify the precision ofthe procedure in this test method for measuring the size ofIridium-192 radiographic sources because round robin testinghas not yet been accomplished.10.2 BiasNo information can be presented on the bias ofthe procedure i
47、n this test method for measuring the size ofIridium-192 radiographic sources because round robin testinghas not yet been accomplished.11. Keywords11.1 cylinder(s); Iridium 192; radiographic source; refer-ence sample; source size; sphereASTM International takes no position respecting the validity of
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49、evision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address sho
