1、Designation: E1079 10Standard Practice forCalibration of Transmission Densitometers1This standard is issued under the fixed designation E1079; 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 p
2、arentheses indicates the year of last reapproval. Asuperscript epsilon () 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 st
3、andard 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 informat
4、ion on the design and use of densitom-eters, the following literature is suggested as additional backgroundinformation: ISO 51:2009, ISO 52:2009, and ISO 14807:2001.2. Referenced Documents2.1 ASTM Standards:3E1316 Terminology for Nondestructive Examinations2.2 ISO Standards:4ISO 51:2009 Photography
5、and graphic technology - Den-sity measurements - Part 1: Geometry and functionalnotationISO 52:2009 Photography and graphic technology - Den-sity measurements - Part 2: Geometric conditions fortransmittance densityISO 14807:2001 Photography - Transmission and reflectiondensitometers - Method for det
6、ermining performance3. Terminology3.1 DefinitionsFor definitions of terms used in this prac-tice, see Terminology E1316.4. Significance and Use4.1 This practice provides a means for calibrating transmis-sion densitometers used for the measurement of radiographicfilm density. A transmission densitome
7、ter calibrated in accor-dance with this practice provides the 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 (X-Ray Film Step Tabl
8、etTransmission Density Standard 38100C)5or alternately a steptablet from another supplier, which is traceable to the NISTstep tablet. The step tablet shall have at least five step densities,which cover the density range that is used for productionradiographs. A calibration certificate shall be provi
9、ded with thestep tablet indicating the tablet ID and recorded values for eachstep density. For suppliers of step tablets other than NIST, thecertificate shall indicate conformance of traceability to NISTinstrumentation used in the calibration process, applicableANSI standards used, verification of m
10、easurement on a NISTstep tablet, the ID number of the step tablet, and calibrationdate of the step tablet. Precautions should be taken in thestorage, handling, and use of the step tablet. In the event itbecomes scratched, blemished, or exhibits other signs ofdeleterious wear, it should be replaced i
11、mmediately. The NIST(or alternate, if used) step tablet shall be replaced four yearsfrom the date of first use.61This practice is under the jurisdiction of ASTM Committee E07 on Nonde-structive Testing and is the direct responsibility of Subcommittee E07.01 onRadiology (X and Gamma) Method.Current e
12、dition approved June 1, 2010. Published July 2010. Originally approvedin 1985. Last previous edition approved in 2005 as E1079 - 05. DOI: 10.1520/E1079-10.2For ASME Boiler and Pressure Vessel Code applications see related PracticeSE-1079 in Section II of that Code.3For referenced ASTM standards, vis
13、it 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. 43rd St.,4th Floor, New York
14、, NY 10036.5Available from National Institute of Standards and Technology (NIST), 100Bureau Dr., Stop 1070, Gaithersburg, MD 20899-1070, http:/www.nist.gov.6Expiration interval of the NIST or alternate step tablet may be different than therequirements of this practice. Unless otherwise specified, re
15、quirements of thispractice shall apply.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.1.2 Transmission Densitometers, with either direct-scalereadout or digital readout displays specifically manufacturedfor the purpose of measurin
16、g the range of film densitiesdescribed in 5.1.1 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
17、 warm-up timeto stabilize circuitry before starting the calibration procedure orthe periodic verification checks described in Section 7. Adjustthe “0” reading of the densitometer after the warm-up period.6.1.2 Select and measure three steps on the calibrated steptablet densities below, above, and ne
18、ar the midpoint of therange that is used for production radiographs.6.1.3 Compare the measured 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 recommendation
19、s, in order toachieve measured densities which are as close as possible tothe actual density values on the step tablet. If the densitometerhas been calibrated properly, the measured densities at thethree steps should not vary more than 60.05 density units fromthe actual step tablet density values. I
20、f any of the measureddensity values vary more than 60.05 density units from thedensity values on the step tablet, the linearity of the densito-meter is out of tolerance and should be taken out of serviceuntil corrected and recalibrated.6.2 Any densitometer that is dropped, repaired, or has hadcritic
21、al parts replaced should be recalibrated prior to use.7. Periodic Verification7.1 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 first.7
22、.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. If thedensity values are not within the tolerance, recalibration isrequired and it shall be performed in accordance with
23、 Section6.7.1.2 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 beenrecalibrated.7.2 Consult the Manufacturers Technical M
24、anual fortroubleshooting information.8. Records and Associated Documentation8.1 Note the densitometer calibration and periodic verifica-tion acceptance condition in an appropriate log. This log shallalso indicate the date the calibration/verification was per-formed and the identification of the indi
25、vidual who performedthe calibration/verification and shall be traceable to the appli-cable densitometer. The retention period for calibration/verification documentation should be agreed upon by thepurchaser and supplier.8.2 An alternative calibration/verification documentationsystem may be used prov
26、ided the calibration/verification trace-ability requirements identified in 8.1 can be satisfied anddocumented properly. A pressure sensitive label or tag thatindicates the date the calibration/verification was performed,and the identification of the individual performing thecalibration/verification,
27、 may be applied to the densitometer forverification of the calibration reference check recorded in thecalibration/verification log.8.3 Note and record the date of first use of the calibration/verification step tablet so that the requirements of 5.1.1 can besatisfied.9. Keywords9.1 calibration; densi
28、tometer; density; periodic verification;radiographic filmASTM International takes no position respecting the validity 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 paten
29、t 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 committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited eithe
30、r 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 he
31、aring 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, 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/).E1079 102
