1、Designation: E2003 10Standard Practice forFabrication of the Neutron Radiographic Beam PurityIndicators1This standard is issued under the fixed designation E2003; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last rev
2、ision. 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 material and fabrication of aBeam Purity Indicator (BPI), which can be used to determinethe relative
3、quality of radiographic images produced by direct,thermal neutron radiographic examination.1.2 The values stated in SI units are regarded to be standard.1.3 This standard does not purport to address the safetyconcerns, if any, associated with its use. It is the responsibilityof the user of this stan
4、dard to establish appropriate safety andhealth practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E543 Specification for Agencies Performing Nondestruc-tive TestingE545 Test Method for Determining Image Quality in DirectThermal
5、Neutron Radiographic ExaminationE748 Practices for Thermal Neutron Radiography of Mate-rialsE1316 Terminology for Nondestructive Examinations3. Terminology3.1 Definitions For definitions of terms used in thispractice, see Terminology E1316, Section H.4. Summary of Practice4.1 The BPI is used for qua
6、ntitative determination ofthermal neutron radiographic quality. It consists of a polytet-rafluoroethylene block containing two boron nitride disks, twolead disks and two cadmium wires. A key feature of the deviceis the ability to make visual analysis of its image for subjectivequality information. D
7、ensitometric measurements of the imageof the device permit quantitative determination of radiographiccontrast, low-energy photon contribution, pair production con-tribution, image unsharpness, and information regarding filmand processing quality.4.2 Neutron radiography practices are discussed in Pra
8、cticeE748.5. Significance and Use5.1 The BPI is designed to yield quantitative informationconcerning neutron beam and image system parameters thatcontribute to film exposure and, thereby, affect overall imagequality. For proper measurements of film exposure due to theneutron beam constituents, the B
9、PI must be fabricated inaccordance with this practice.5.2 This practice shall be followed for the fabrication of allBeam Purity Indicators to be used with Method E545 todetermine image quality in direct thermal neutron radiography.6. Basis of Application6.1 Qualification of Nondestructive AgenciesIf
10、 specifiedin the contractual agreement, NDT agencies shall be qualifiedand evaluated as described in Practice E543. The applicablerevision of Practice E543 shall be specified in the contractualagreement.6.2 Procedures and TechniquesThe procedures and tech-niques to be utilized shall be as described
11、in this practice unlessotherwise specified. Specific techniques may be specified in thecontractual agreement.6.3 Reporting Criteria/Acceptance CriteriaReporting cri-teria for the examination results shall be in accordance withSections 9 and 10 unless otherwise specified. Acceptancecriteria, for exam
12、ple, for reference radiographs, shall bespecified in the contractual agreement.6.4 Reexamination of Repaired/Reworked ItemsReexamination of repaired/reworked items is not addressed inthis practice and, if required, shall be specified in the contrac-tual agreement.7. Beam Purity Indicator (BPI)7.1 Th
13、e BPI shall be constructed of polytetrafluoroethylene,cadmium, lead, and boron nitride.1This practice is under the jurisdiction of ASTM Committee E07 on Nonde-structive Testing and is the direct responsibility of Subcommittee E07.05 onRadiology (Neutron) Method.Current edition approved Jan. 1, 2010.
14、 Published February 2010. Originallyapproved in 1998. Last previous edition approved in 2004 as E2003 - 98(2004).DOI: 10.1520/E2003-10.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume inf
15、ormation, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.7.2 The construction and dimensions shall be as shown inFig. 1.7.3 The BPI may be encased in a frame for easy m
16、ounting,but shall not be enclosed in a dust cover nor shall any materialcover either side of the BPI face.7.4 Cadmium and lead shall be at least 99.9 % pure elemen-tal material.7.5 Boron nitride shall be hot-pressed, minimum 40 %elemental boron.7.6 The polytetrafluoroethylene block tolerances shall
17、be610 %.7.7 The tolerances for the holes and the grooves shall besuch that the disks and the wires do not fall out during use.8. Fabrication8.1 Individual Components:8.1.1 Form the polytetrafluoroethylene base by milling an8-mm thick sheet of the material into a 25-mm square.8.1.2 Drill a 16 6 1-mm
18、hole in the center of the unit.8.1.3 Mill two 4-mm diameter by 2-mm deep holes centered4-mm from adjacent corners on one face of the unit.8.1.4 Cut two lengths of 0.7 6 0.1-mm diameter cadmiumwire, each 12-mm long.8.1.5 Mill a groove in the base between the holes milled in8.1.3. The groove should be
19、 0.04 mm deeper and 0.04 mmnarrower than the diameter of the wire cut in 8.1.4, so the wirewill be flush and tight. The groove may extend to the outsideedge of the unit (see Fig. 1).8.1.6 Repeat the process on the opposite face, makingcertain that the holes are not stacked upon each other.8.1.7 Prep
20、are a 4-mm diameter rod of boron nitride (a lathemay be used).8.1.8 Cut off two 2-mm thick disks from the rod machinedin 8.1.7.8.1.9 Prepare a 4-mm diameter rod of lead (a lathe may beused).8.1.10 Cut off two 2-mm thick disks from the rod machinedin 8.1.9.8.2 Assembly:8.2.1 Place the polytetrafluoro
21、ethylene block with the twoholes and groove on the left side.8.2.2 Insert a lead disk (as prepared in 8.1.9 and 8.1.10)inthe upper hole.8.2.3 Insert a boron nitride disk (as prepared in 8.1.7 and8.1.8) in the lower hole.8.2.4 Insert a cadmium wire piece (as prepared in 8.1.4) intothe groove between
22、the two disks, making certain the wire isflush, tight, and centered.8.2.5 Turn the block over and orient it so that the groove andholes are on the left side. Repeat the steps specified in 8.2.1through 8.2.4.8.2.6 The final assembly shall conform to Fig. 1.9. Certification9.1 Upon request of the purc
23、haser by contract or purchaseorder, any fabricator of the BPI described in this practice shallprovide materials certification. To verify correct assembly andfunctionality, a comparison thermal neutron radiograph of theassembled BPI and a reference BPI shall be provided.PolytetrafluoroethyleneCadmium
24、 99.9 % pureLead 99.9 % pureBN-Boron nitrideHot-pressed, 40 % min elemental boronNOTE 1Pb and BN disks are 4-mm in diameter and 2-mm thick (minimum thickness).FIG. 1 Beam Purity IndicatorE2003 1029.2 The comparison thermal neutron radiograph of theassembled BPI along with a reference BPI shall show
25、thefollowing:9.2.1 The disks and wires are properly placed and intact.9.2.2 Using Method E545 (latest revision), calculate thevalues for thermal neutron, scattered neutron, gamma, and pairproduction content.9.2.3 The values should be comparable to those of thereference BPI.9.2.4 Assign a unique iden
26、tification number to the accept-able unit and mark the BPI. The identification number shall besuch that it shall not interfere with any density readings used tocalculate any exposure contributors (see Method E545, latestrevision).9.3 The comparison thermal neutron radiograph of theassembled BPI with
27、 the reference BPI shall meet quality levelCategory I specified in Method E545, latest revision.9.4 Any BPI fabricated in accordance with Method E545from 1981 through 1991 is acceptable as a reference BPI(unless there is known to be a disqualifying deficiency).10. Records10.1 Complete records of the
28、 fabrication details shall bemaintained by the manufacturing facility for three years or asspecified in the basis of purchase.11. Keywords11.1 beam purity indicator; direct method; image qualityindicator; neutron radiography; sensitivity indicatorASTM International takes no position respecting the v
29、alidity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is s
30、ubject to revision 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 Headq
31、uarters. 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 shown below.This stan
32、dard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).E2003 103
