ASTM F2547-2018 Standard Test Method for Determining the Attenuation Properties in a Primary X-ray Beam of Materials Used to Protect Against Radiation Generated During the Use of X.pdf

1、Designation: F2547 06 (Reapproved 2013)F2547 18Standard Test Method forDetermining the Attenuation Properties in a Primary X-rayBeam of Materials Used to Protect Against RadiationGenerated During the Use of X-ray Equipment1This standard is issued under the fixed designation F2547; the number immedia

2、tely following the designation indicates the year oforiginal adoption or, in the case of revision, the year of 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 te

3、st method establishes procedures for measuring the attenuation of X-rays by protective materials at acceleratingpotentials from 60 to 130 kVp.1.2 This test method provides attenuation values of primary beam X-radiation.1.3 This test method applies to both leaded and non-leaded radiation protective c

4、lothing materials.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine theapplicability of regula

5、tory limitations prior to use.1.5 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organiz

6、ation Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2F1494 Terminology Relating to Protective Clothing3. Terminology3.1 Definitions:3.1.1 attenuation, nForfor radiological protective material, the reduction in the intensity of the X-ray beam resulting from the

7、interactions between the X-ray beam and the protective material that occur when the X-ray beam passes through the protectivematerial.3.1.1.1 DiscussionIn this test method, the attenuation is calculated as 1 minus the ratio of the measured exposure with a protective material in thebeam to the measure

8、d exposure without the protective material in the beam at a specific accelerating potential. Multiplying theresulting value by 100 gives percent attenuation.Attenuation percent!5S12 exposure with sampleexposure without sampleD3100 (1)3.1.2 lead equivalency, coeffcient of variation, nFor radiological

9、 protective material, the thickness in millimetres of lead(commonly designated mmPb) of greater than 99.9 percent purity that provides the same attenuation as a given protectivematerial.the ratio of the standard deviation of a sample to the sample mean.1 This test method is under the jurisdiction of

10、 ASTM Committee F23 on Personal Protective Clothing and Equipment and is the direct responsibility of SubcommitteeF23.70 on Radiological Hazards.Current edition approved July 1, 2013Jan. 1, 2018. Published July 2013January 2018. Originally approved in 2006. Last previous edition approved in 20062013

11、 as F2547- 06. DOI: 10.1520/F2547-06R13. 06 (2013). DOI: 10.1520/F2547-18.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the

12、ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users cons

13、ult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.1.2.1 DiscussionThis test method

14、provides the attenuation of the material and not the lead equivalency. Determining lead equivalency would requiretesting lead of known thickness and purity, and comparing the attenuation of the protective material with the attenuation of the lead.Although lead equivalency has been the standard for r

15、eporting protective material capability, the drafters of this test method believeit is not feasible to obtain adequate standard lead samples for reporting lead equivalency values.3.1.3 secondary radiation, exposure, nradiation outside the primary X-ray beam.for radiological purposes, the amount ofio

16、nization in air at standard conditions caused by interaction with X-rays, expressed in units of Roentgen (R) or milliroentgen(mR). The SI units are Coulomb per kilogram (C/kg). 1 Roentgen = 2.58 104 C/kg.3.1.4 scatter radiation, na form of secondary radiation resulting from the interaction of the pr

17、imary X-ray beam and the target(for example, protective material being tested or a patient undergoing a medical procedure).3.1.4 half-value layer (HVL), nthe thickness of aluminum, in millimetres (commonly designated mmAl), that reduces theintensity of the X-ray beam by one half.3.1.4.1 DiscussionTh

18、e HVL is dependent on the energy of the X-ray beam and, therefore, is different for X-rays produced at different acceleratingpotentials.3.1.6 kilovolts, peak (kVp), nthe maximum electrical potential across an X-ray tube during an exposure, expressed in kilovolts.3.1.7 exposure, nfor radiological pur

19、poses, the amount of ionization in air at standard conditions caused by interaction withX-rays, expressed in units of Roentgen (R) or milliroentgen (mR).3.1.8 wave form ripple, nfor radiological purposes, the peak-to-peak variation in the output voltage of the X-ray generator.3.1.5 ionization chambe

20、r, na device that measures the electrical charge liberated during the ionization of air molecules byelectromagnetic radiation (X-rays for the purposes of this test method), expressed in units of coulombs per kilogram of air.3.1.6 kilovolts, peak (kVp), nthe maximum electrical potential across an X-r

21、ay tube during an exposure, expressed in kilovolts.3.1.7 lead equivalency, nfor radiological protective material, the thickness in millimetres of lead (commonly designatedmmPb) of greater than 99.9 % purity that provides the same attenuation as a given protective material.3.1.7.1 DiscussionThis test

22、 method provides the attenuation of the material and not the lead equivalency. Determining lead equivalency would requiretesting lead of known thickness and purity, and comparing the attenuation of the protective material with the attenuation of the lead.The lead equivalency may be determined based

23、on published half or tenth thickness values. When lead equivalency is stated, thesource of published values shall be stated as the basis of calculation.X 5lnSIIoD2en (2)where:X = Pb equivalency,I/Io = attenuation (fraction) = incident intensity/transmitted intensity, anden = Pb energy absorption coe

24、fficient at test energy, cm1.3.1.8 scatter radiation, na form of secondary radiation resulting from the interaction of the primary X-ray beam and the target(for example, protective material being tested or a patient undergoing a medical procedure).3.1.9 secondary radiation, nradiation outside the pr

25、imary X-ray beam.3.1.10 shielding, nfor radiological purposes, any material or obstruction that attenuates radiation to protect personnel orequipment from the effects of ionizing radiation.3.1.11 coeffcient of variation,wave form ripple, nthe ratio of the standard deviation of a sample to the sample

26、 mean.forradiological purposes, the peak-to-peak variation in the output voltage of the X-ray generator.3.1.12 For definitions of other terms related to protective clothing used in this test method, refer to Terminology F1494.3.2 For definitions of other terms related to protective clothing used in

27、this test method, refer to Terminology F1494.4. Summary of Test Method4.1 A primary X-ray beam with a standardized energy spectrum and constant intensity is configured to pass through the testset-up. An ionization chamber, calibrated for the energy range of X-rays produced at accelerating potentials

28、 between 60 to 130F2547 182kVp, is used to measure the exposure in the primary beam with and without the material specimen positioned between the X-raysource and the ionization chamber. The exposure is directly proportional to the intensity of the X-ray beam. The attenuationprovided by the material

29、specimen is defined as the percentage of the original beam intensity that is removed by the materialspecimen.4.2 The attenuation of the sample is determined at an X-ray energy in the range produced by an accelerating potential from 60to 130 kVp.5. Significance and Use5.1 This test method is intended

30、 to provide a standardized test procedure of protective materials to ensure comparable resultsamong manufacturers and users.5.2 This test method involves measurement of the attenuation of X-rays by protective clothing material at an acceleratingpotential (kVp) between 60 and 130 kVp. These energies

31、are considered to be representative of those commonly used duringmedical diagnosis and treatment.diagnosis.5.3 The reporting of the attenuation at a specific X-ray energy is intended to allow the end user organization to assess theattenuating properties of the protective clothing material at that en

32、ergy level.6. Apparatus6.1 Primary X-ray Beam SourceA variable power high frequency power, high-frequency X-ray generator coupled with X-raytube equipped with Tungsten anode with the following characteristics:6.1.1 The wave form ripple does not exceed three percent.3 %.6.1.2 The coefficient of varia

33、tion for the exposure does not exceed 0.05 as determined using four consecutive exposures.6.1.3 The coefficient of variation for kVp does not exceed 0.05 determined using four consecutive test measurements at the kVpsetting used in testing.6.2 An invasive or non-invasive kVp measuring device capable

34、 of measuring the kVp accuracy within 0.5 kVp.6.3 An ionization chamber and electrometer capable of measuring from 1 mR to 5 R.6.4 Shielding material may be used around apparatus to improve precision.7. Hazards7.1 All individuals performing tests using this test method shall wear X-ray protective cl

35、othing or be positioned behindstationary shielding when the X-ray beam is activated.7.2 All individuals performing tests using this test method shall be monitored for radiation exposure by wearing personaldosimetry commensurate with the testing facilities radiation safety programs.8. Sampling and Te

36、st Specimens8.1 Test specimens may come from protective material sheets or from protective material obtained from garments.8.1.1 Specimens may be single sheets or multiple sheets tested as a stack, as appropriate for the application. When multiplesheets are tested as a stack, the stack should be as

37、flat as possible and air voids between single sheets should be minimized to theextent practical.8.2 Randomly select a total of five specimens from the material or protective clothing sample for evaluation.8.3 Test specimens shall have a circular or square shape with an area sufficient for testing.su

38、fficient area for testing, that is, belarge enough to fully intercept the area of the X-ray field at the location of placement of the test specimens.9. Preparation of Apparatus9.1 Measure and document the kVp accuracy for each kVp setting used in the testing prior to every testing session.9.1.1 If t

39、he length of the testing session exceeds 1 h, measure and document kVp accuracy at least once each hour.9.2 Measure and document the exposure reproducibility of the combination of tube current and exposure time used in the testingprior to every testing session.9.2.1 If the length of the testing sess

40、ion exceeds one hour measure and document kVp accuracy at least once each hour.9.3 Measure and document HVL for the kVp setting used in the testing at the beginning of the testing session.9.4 Measure and document the kVp accuracy for the kVp setting used in the testing at the end of the testing sess

41、ion.10. Calibration and Standardization10.1 The kVp meter and ionization chamber shall be calibrated not less than annually to NIST-traceable standards.F2547 18310.2 At the desired kVp setting determine the half-value layer in millimetres of type 1100 aluminum (mm Al). (mmAl). Thehalf-value layer sh

42、all fall within 0.1 mm Al mmAl of the value specified in Table 1.10.3 The focal spot size shall be as small as practicable.11. Conditioning11.1 There are no special conditioning requirements for the test.12. Procedure12.1 Set the X-ray accelerating potential to the desired kVp for the X-ray beam sou

43、rce.12.2 Set the distance between the focal spot to the specimen at 400 mm 1534 in. and the distance between the ionizationchamber and the specimen at 1000 mm 3938 in.12.3 Ensure that the closest source of back-scatter (such as a table top or the floor) is not less than 450 mm 1734 in. from theioniz

44、ation chamber.12.4 Set the X-ray field dimensions to match the dimensions of the ionization chamber.12.4.1 Ensure that the X-ray field does not exceed the size of the specimen.12.5 Conduct one exposure measurement without a specimen in the X-ray beam and record the exposure reading from theexposure

45、meter.12.6 Place a specimen in the field.12.7 Perform two exposure measurements with the specimen in the X-ray beam and record the exposure readings from theexposure meter.12.7.1 The exposure measurements acquired with the specimen in the beam shall not vary by more than three percent.3 %.12.8 Condu

46、ct a post-specimen exposure measurement with no specimen in the X-ray beam.12.8.1 The second no-specimen exposure measurement shall not vary from pre-specimen exposure by more than three percent.3%.12.9 Repeat measurements for remaining specimens.13. Calculations13.1 Calculate the arithmetic mean (s

47、imple average) exposure with no specimen in the X-ray beam for all no-specimenmeasurements. This value becomes the mean exposure (no specimen).13.2 Calculate the mean of the exposures with a specimen in the X-ray beam for all measurements involving a specimen. Thisvalue is the mean exposure (with sp

48、ecimen).13.3 Calculate the attenuation for the protective clothing material.14. Report14.1 State that the test was conducted as directed in Test Method F2547 - 06.F2547 18.14.2 Provide the following information with each test set:14.2.1 Test InformationDate of testing, place of testing, name of indi

49、vidual(s) performing the testing, equipment(manufacturer and model of X-ray generator and X-ray tube) used in testing, test parameters (kVp, HVLAl mm,mmAl , current,exposure time)time).14.2.2 Sample IdentificationDescription of the material tested (indicate, as applicable and available: manufacturer, type ofmaterial, presence of coatings, number of sheets, other identifying data).14.2.3 The attenuation for each of the five samples and the mean attenuation.15. Precision and Bias15.1 PrecisionThe precision of the procedure in this test