1、BS EN12543-2:2008ICS 19.100NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDNon-destructive testing Characteristicsof focal spots inindustrial X-raysystems for use in non-destructive testingPart 2: Pinhole camera radiographicmethodThis British Standardwas publish
2、ed under theauthority of the StandardsPolicy and StrategyCommittee on 31 July 2008 BSI 2008ISBN 978 0 580 55872 6Amendments/corrigenda issued since publicationDate CommentsBS EN 12543-2:2008National forewordThis British Standard is the UK implementation of . It supersedes BSEN 12543-2:1999 which is
3、withdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee WEE/46, Non-destructive testing.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisionsof a contrac
4、t. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunityfrom legal obligations.BS EN 12543-2:2008EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN 12543-2July 2008ICS 19.100 Supersedes EN 12543-2:1999 English VersionNon-destructive testing - Char
5、acteristics of focal spots inindustrial X-ray systems for use in non-destructive testing - Part2: Pinhole camera radiographic methodEssais non destructifs - Caractristiques des foyersmissifs des tubes radiognes industriels utiliss dans lesessais non destructifs - Partie 2: Mthode radiographiquepar s
6、tnopZerstrungsfreie Prfung - Charakterisierung vonBrennflecken in Industrie-Rntgenanlagen fr diezerstrungsfreie Prfung - Teil 2: RadiographischesLochkamera-VerfahrenThis European Standard was approved by CEN on 7 June 2008.CEN members are bound to comply with the CEN/CENELEC Internal Regulations whi
7、ch stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the CEN Management Centre or to any CEN member.This European Stan
8、dard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as theofficial versions.CEN members are the national stand
9、ards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingd
10、om.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2008 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 12543-2:2008: EBS EN 125
11、43-2:2008EN 12543-2:2008 (E) 2 Contents Page Foreword3 Introduction .4 1 Scope 5 2 Normative references 5 3 Terms and definitions .5 4 Test equipment 5 5 Measurement and determination of the focal spot size.8 Annex A (informative) Preferred values of d for the characterization of X-ray tube types10
12、Bibliography 11 BS EN 12543-2:2008EN 12543-2:2008 (E) 3 Foreword This document (EN 12543-2:2008) has been prepared by Technical Committee CEN/TC 138 “Non-destructive testing”, the secretariat of which is held by AFNOR. This European Standard shall be given the status of a national standard, either b
13、y publication of an identical text or by endorsement, at the latest by January 2009, and conflicting national standards shall be withdrawn at the latest by January 2009. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or C
14、ENELEC shall not be held responsible for identifying any or all such patent rights. This document supersedes EN 12543-2:1999. EN 12543-2 is part of a series of European Standards under the general title Non-destructive testing Characteristics of focal spots in industrial X-ray systems for use in non
15、-destructive testing; the other Parts are the following: EN 12543-1: Part 1: Scanning method; EN 12543-3: Part 3: Slit camera radiographic method; EN 12543-4: Part 4: Edge method; EN 12543-5: Part 5: Measurement of the effective focal spot size of mini and micro focus X-ray tubes. According to the C
16、EN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
17、 Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. BS EN 12543-2:2008EN 12543-2:2008 (E) 4 Introduction In order to cover the different requirements for focal spot size measurement, five different methods are des
18、cribed in EN 12543-1 to EN 12543-5. The scanning method (EN 12543-1) is dedicated to those applications where quantitative values for the intensity distribution and spot size are needed, i.e. calibration and image processing purposes. The radiographic methods (EN 12543-2 and EN 12543-3) describe the
19、 traditional techniques and are dedicated for certification purposes and for field applications. A digital detector not only provides focal spot length and width, but also the user with quantitative values for intensity distribution. The digital method may be used as a reference method as in EN 1254
20、3-1 Where no pinhole or slit cameras are available in the field, the edge method (EN 12543-4) may be applied. It represents a very simple method for field application. For micro focus systems, see EN 12453-5. BS EN 12543-2:2008EN 12543-2:2008 (E) 5 1 Scope This European Standard specifies a method f
21、or the measurement of focal spot dimensions above 0,2 mm of X-ray systems up to and including 500 kV tube voltage by means of the pinhole camera radiographic method. The voltage applied for this measurement is restricted to 200 kV for visual film evaluation. The image quality and the resolution of X
22、-ray images depend highly on the characteristics of the focal spot, in particular the size and the two dimensional intensity distribution. For the characterisation of commercial X-ray tube types (i.e. for advertising or trade) the specific values of Table A.1 are used. 2 Normative references The fol
23、lowing referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 462-5, Non-destructive testing Image quality of radio
24、graphs Part 5: Image quality indicators (duplex wire type), determination of image unsharpness value EN 584-1, Non-destructive testing Industrial radiographic film Part 1: Classification of film systems for industrial radiography EN 12543-1:1999, Non-destructive testing Characteristics of focal spot
25、s in industrial X-ray systems for use in non-destructive testing Part 1: Scanning method 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 focal spot X-ray emitting area on the anode of the X-ray tube as seen from the measuring device EN 12543-
26、1:1999 4 Test equipment 4.1 Essential characteristics of the pinhole The pinhole camera shall consist of a diaphragm with a pinhole having the following dimensions according to Table 1 dependent from the actual focal spot size: Table 1 Dimensions of the pinhole Focal spot size mm Diameter P m Height
27、 H m 0,2 to 1,0 30 5 75 10 1,0 100 5 500 10 BS EN 12543-2:2008EN 12543-2:2008 (E) 6 The dimensions P and H are given in Figure 1. Dimensions in millimetres Key 1 focal spot Figure 1 Essential dimensions of a pinhole diaphragm The pinhole diaphragm shall be made of tungsten or of a similar absorbant
28、material. 4.2 Alignment and position of the pinhole camera The angle between the beam direction and the pinhole axis (see Figure 2) shall be smaller than 3. When deviating from Figure 2, the direction of the beam shall be indicated. Key 1 focal spot 2 beam direction 3 maximum deviation of the axis o
29、f the pinhole Figure 2 Alignment of the pinhole camera BS EN 12543-2:2008EN 12543-2:2008 (E) 7 The incident face of the pinhole diaphragm shall be placed at a distance m from the focal spot so that the variation of the magnification over the extension of the actual focal spot does not exceed 5 % in
30、the beam direction. In no case shall this distance be less than 100 mm. 4.3 Position of the radiographic image detector The radiographic image detector shall be placed normal to the beam direction at a distance n from the incident face of the pinhole diaphragm determined from the applicable magnific
31、ation according to Figure 3 and Table 2. Key 1 plane of anode 2 reference plane 3 radiographic image detector 4 magnified length of the effective focal spot 5 beam direction 6 incident face of the diaphragm 7 physical length of the actual focal spot Figure 3 Beam direction dimensions and planes BS E
32、N 12543-2:2008EN 12543-2:2008 (E) 8 Table 2 Magnification for focal spot pinhole radiographs Focal spot size d mm Minimum magnification n/m 0,2 to 2,0 3: 1 2,0 1: 1 4.4 Requirements on the radiographic image detector Radiographic films or digital radiographic detectors can be used, provided sensitiv
33、ity, dynamic range and detector unsharpness allow capturing of the full spatial size of the focal spot image without detector saturation. The maximum allowed detector unsharpness is given by the geometrical unsharpness uGof the pin hole and is calculated according to: ()mnPu /1G+= (1) The detector u
34、nsharpness shall be determined with the duplex wire IQI according to EN 462-5. For correct quantitative measurements the minimum projected length and width of the focal spot image should be covered always by at least 20 detector pixels. The signal-to-noise ratio of the focal spot image (ratio of the
35、 maximum intensity value inside the focal spot and the standard deviation of the background signal outside) should be at least 50. The maximum intensity inside the focal spot should be above 50 %, but lower than 100 % of the maximum linear detector output value to achieve an image with good contrast
36、. Imaging plates systems (Computed Radiography, CR) or digital detector arrays (e.g. based on CCD-, a-Si- or CMOS-detectors coupled to an X-ray fluorescent screen, direct converting detectors or image intensifiers with CCD cameras) may be used as digital image detectors. If radiographic film is used
37、 as image detector, it shall meet the requirements of the film system class C 6 or better according to EN 584-1 and shall be used without screens. The film shall be exposed to give a maximum optical density between 1,5 and 2,5. For reference measurements, the film can be digitised with a maximum pix
38、el size, which fulfils the requirements of the above unsharpness conditions, and evaluated according to 5.1. 4.5 Loading factors The X-ray tube voltage shall be 75 % of the nominal tube voltage, but not more than 200 kV for visual film evaluation. For digital evaluation the maximum voltage is limite
39、d by the need that the background intensity is lower than half of the maximum intensity inside the focal spot. The X-ray tube current shall be the maximum applicable tube current at the selected voltage. 5 Measurement and determination of the focal spot size 5.1 Measurement The grey scale image of t
40、he radiation detector shall be proportional to the X-ray dose. It shall be evaluated to measure the dimensions of the focal spot. The area of all pixels of the focal spot image with grey values higher than 10% of the maximum value (of a 3x3 pixel median filtered image to suppress outliers) above bac
41、kground intensity are used to represent the area of the focal spot (see Figure 4). An isodose contour plot at 10% of the maximum intensity (see Figure 6 in EN 12543-1:1999) may also be used to indicate the area of the focal spot. The focal spot size is determined by the extent of the focal spot area
42、 in x- and y-direction divided by the magnification factor (n/m) of the pinhole camera. If radiographic film is used as an image detector, it is evaluated visually using an illuminator with a uniform luminance of 2000 cd/m to 3000 cd/m. The visual evaluation shall be carried out using an X5 or X10 B
43、S EN 12543-2:2008EN 12543-2:2008 (E) 9 magnifying glass, with a built-in reticle, with divisions of 0,1 mm. The resulting focal spot is defined by the visible extent of the blackened area, divided by the selected magnification factor. Key a) grey scale image, which is proportional to the X-ray dose,
44、 from a radiographic image detector (e.g. CR) b) evaluation result (binary image) based on a 10 % threshold between background intensity and maximum intensity of the focal spot image Figure 4 Evaluation of focal spot images 5.2 Determination of focal spot size Each focal spot size is described by it
45、s size l (length) in the direction of the tube axis and its size w (width) across the X-ray tube. The operating parameters of the X-ray tube shall be recorded. If the tube axis is not defined, then the direction of the electron trajectory is used instead. The larger of these sizes (l or w) shall be
46、used as the “focal spot size d“. A specification of the focal spot sizes d on the X-ray tube shall refer to this European Standard. If the focal spot size will be certified, the measurement result has to meet the values of EN 12543-1 within an uncertainty of 10 %. This is fulfilled if the focal spot
47、 image is acquired digitally considering the requirements of 4.4, 4.5 and 5.1. NOTE ASTM E 1165 describes a different test method for determination of focal spot sizes of X-ray tubes by the pin hole method. The user of this CEN standard should note that the ASTM standard provides smaller values due
48、to a different measurement procedure. BS EN 12543-2:2008EN 12543-2:2008 (E) 10 Annex A (informative) Preferred values of d for the characterization of X-ray tube types Table A.1 Preferred values of d in millimetres 0,1 0,15 0,2 0,3 0,4 0,5 0,6 0,8 1,0 1,4 1,8 2,2 2,6 3,0 3,5 4,0 4,5 5,0 5,5 6,0 7,0
49、8,0 9,0 10,0 Additionally to d, the dimensions of l and w can be indicated in the same steps. BS EN 12543-2:2008EN 12543-2:2008 (E) 11 Bibliography 1 ASTM E 1165, Standard Test Method for Measurement of Focal Spots of Industrial X-Ray Tubes by Pinhole Imaging BS EN12543-2:2008BSI GroupHeadquarters 389Chiswick High Road,London, W4 4AL, UKTel +44 (0)20 8996 9001Fax +44 (0)20 8996 - British Standards InstitutionBSI is the independent national body responsible for preparing BritishStandar
