1、Designation: E 1079 05Standard Practice forCalibration of Transmission Densitometers1This standard is issued under the fixed designation E 1079; 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
2、 parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice2covers the calibration of transmissiondensitometers used to perform radiographic film density mea-surements (see Note 1).1.2 This
3、 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.NOTE 1For further infor
4、mation on the design and use of densitom-eters, the following literature is suggested as additional backgroundinformation: ISO 52:2001, ISO 51:2001, and ISO 14807:2001.2. Referenced Documents2.1 ASTM Standards:3E 1316 Terminology for Nondestructive Examinations2.2 ISO Standards:4ISO 52:2001 Photogra
5、phy-Density MeasurementsPart2: Geometric Conditions for Transmission DensityISO 51:2001 Photography-Density MeasurementsPart1: Terms, Symbols, and NotationsISO 14807:2001 Photography-Transmission and ReflectionDensitometersMethod for Determining Performance3. Terminology3.1 DefinitionsFor definition
6、s of terms used in this prac-tice, see Terminology E 1316.4. Significance and Use4.1 This practice provides a means for calibrating transmis-sion densitometers used for the measurement of radiographicfilm density. A transmission densitometer calibrated in accor-dance with this practice provides the
7、assurance that accuratedensity values of radiographs are obtained.5. Apparatus5.1 Apparatus should consist of the following:5.1.1 A calibrated step tablet shall be used. The step tabletmay be a NIST X-ray Step Tablet (Standard Reference MaterialSRM 1001)5or alternately a step tablet from another sup
8、plierwhich is traceable to the NIST SRM 1001 X-ray Step Tablet.The step tablet shall have at least five step densities rangingfrom 0.9 through 4.1. The step tablet may have additional stepdensities less than 0.9 and greater than 4.1. A calibrationcertificate shall be provided with the step tablet in
9、dicating thetablet ID and recorded values for each step density. Forsuppliers of step tablets other than NIST, the certificate shallindicate conformance of traceability to NIST instrumentationused in the calibration process, applicable ANSI standardsused, verification of measurement on a NIST SRM 10
10、01 steptablet, the ID number of the SRM 1001 step tablet, andcalibration date of the step tablet. Precautions should be takenin the storage, handling, and use of the step tablet. In the eventit becomes scratched, blemished, or exhibits other signs ofdeleterious wear, it should be replaced immediatel
11、y. The SRM1001 (or alternate, if used) step tablet shall be replaced fouryears from the date of first use.65.1.2 Transmission Densitometers, with either direct-scalereadout or digital readout displays specifically manufacturedfor the purpose of measuring the range of film densitiesdescribed in 5.1.1
12、 may be used.5.1.3 Manufacturers Operating Instructions for Appropri-ate Transmission Densitometer.6. Calibration6.1 Full-scale linearity calibration should be performed atleast every 90 days during use as follows:6.1.1 Use the manufacturers recommended warm-up timeto stabilize circuitry before star
13、ting the calibration procedure orthe periodic verification checks described in Section 8. Adjustthe “0” reading of the densitometer after the warm-up period.1This practice is under the jurisdiction of ASTM Committee E07 on Nonde-structive Testing and is the direct responsibility of Subcommittee E07.
14、01 onRadioglogy (X and Gamma) Method.Current edition approved January 1, 2005. Published January 2005. Originallyapproved in 1985. Last previous edition approved in 2000 as E 1079 - 00.2For ASME Boiler and Pressure Vessel Code applications see related PracticeSE-1079 in Section II of that Code.3For
15、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.4Available from American National Standards Institute (ANSI), 25 W
16、. 43rd St.,4th Floor, New York, NY 10036.5Standard Reference Material 1001 is available from the National Institute ofStandards and Technology, Gaithersburg, MD.6Expiration interval of the SRM 1001 or alternate step tablet may be differentthan the requirements of this practice. Unless otherwise spec
17、ified, requirements ofthis practice shall apply.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6.1.2 Select and position for measuring the stable densityclosest to 0.9, 3.0, and 4.1 on the calibrated step tablet.6.1.3 Compare the me
18、asured densities with the actual den-sity values on the calibrated step tablet or the density valueslisted on the calibration certificate. Calibrate the densitometer,in accordance with manufacturer recommendations, in order toachieve measured densities which are as close as possible tothe actual den
19、sity values on the step tablet. If the densitometerhas been calibrated properly, the measured densities at 0.9, 3.0and 4.1 steps should not vary more than 60.05 density unitsfrom the actual step tablet density values. If any of themeasured density values vary more than 60.05 density unitsfrom the de
20、nsity values on the step tablet, the linearity of thedensitometer is out of tolerance and should be taken out ofservice until corrected and recalibrated.6.2 Any densitometer that is dropped, repaired, or has hadcritical parts replaced should be recalibrated prior to use.7. Records and Associated Doc
21、umentation7.1 Note the densitometer calibration acceptance conditionin an appropriate log. This log shall also indicate the date thecalibration was performed and the identification of the indi-vidual who performed the calibration and shall be traceable tothe applicable densitometer. The retention pe
22、riod for calibra-tion documentation should be agreed upon by the purchaserand supplier.7.2 An alternative calibration documentation system may beused provided the calibration traceability requirements identi-fied in 7.1 can be satisfied and documented properly.Apressuresensitive label or tag that in
23、dicates the date the calibration wasperformed, and the identification of the individual performingthe calibration, may be applied to the densitometer for verifi-cation of the calibration reference check recorded in thecalibration log.7.3 Note and record the date of first use of the calibrationstep t
24、ablet so that the requirements of 5.1.1 can be satisfied.8. Periodic Verification8.1 Periodic calibration verification checks using the proce-dure described in Section 6 should be performed at thebeginning of each shift, after 8 h of continuous operation, orchange of apertures, whichever occurs firs
25、t.8.1.1 If the verification reading is within 60.05 of thedensity values listed on the calibration step tablet or calibrationcertificate, the densitometer is ready for continued use. It is notnecessary to record verification results. If the density values arenot within the tolerance, recalibration i
26、s required and it shall beperformed in accordance with Section 6.8.1.2 If the calibration verification check shows a variationgreater than 60.05, then all radiographs examined since thelast acceptable daily density check should be subject to areverification for density after the densitometer has bee
27、nrecalibrated.8.2 Consult the Manufacturers Technical Manual fortroubleshooting information.9. Keywords9.1 calibration; densitometer; density; periodic verification;radiographic filmASTM International takes no position respecting the validity of any patent rights asserted in connection with any item
28、 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 subject to revision at any time by the responsible technical commi
29、ttee 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 me
30、eting 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 standard is copyrighted by ASTM International, 100 Barr Harbor Drive,
31、 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).E1079052
