1、STDaBSI BS EN 12543-3-ENGL 1997 W Lb2LibbS 0839975 480 M BRITISH STANDARD Non-destructive testing - Characteristics of focal spots in industrial X-ray systems for use in non-destructive testing - Part 3: Slit camera radiographic method The European Standard EN 1254331999 has the status of a British
2、Standard ICs 19. loo BS EN 12 543-3: 1999 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW STD=BSI BS EN 12543-3-ENGL 1997 I 1b24bbS 081977b 317 BS EN 12543-3:1999 diredion of the Engineering Amd.No. Date Sector Committee, was published under the authority of the Standards Comm
3、ittee and comes into effect on 15 December 1999 National foreword Comments This British Standard is the English language version of EN 1254331999. The UK participation in its preparation was entrusted to Technical Committee WEW46, Nondestructive testing, which has the responsibility to: - aid enquir
4、em to understand the text; - present to the responsible European committee any enquiries on the - monitor related intemational and European developments and promulgate interpretation, or prop the other parts are the following: EN 12543-1 , Non-destructive testing - Characteristics of focal spots in
5、industrial X-ray systems for use in non- destructive testing - Part 1: Scanning method. EN 12543-2, Non-destructive testing - Characteristics of focal spots in industrial X-ray systems for use in non- destructive testing - Part 2: Pinhole camera radiographic method EN 12543-4, Non-destructive testin
6、g - Charactenstics of focal spots in industrial X-ray systems for use in non- destructive testing - Part 4: Edge method. EN 12543-5, Non-destructive testing - Characteristics of focal spots in industrial X-ray systems for use in non- destructive testing - Part 5: Measurement of the effective focal s
7、pot size of mini and micro focus X-ray tubes. QBSI 12-1999 Page 4 EN 12543-311 999 In trod u ct i o n In order to cover the different requirements for focal spot size measurement, five different methods are described in EN 12543-1 to EN 12543-5. The scanning method (EN 12543-1) is dedicated to those
8、 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 traditional techniques and are dedicated for certification purposes and for field applic
9、ations up to 200 kV. 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. In order to cover also the micro focus systems, a specific method is presented in EN 12543-5. 1 Scope This European
10、 Standard specifies a method for the measurement of focal spot dimensions above 0,l mm of X- ray systems up to and including 500 kV tube voltage by means of the slit camera radiographic method. The voltage applied for this measurement is restricted to 200 kV. The image quality and the resolution of
11、X-ray images depend highly on the characteristics of the focal spot, in particular the size and the twodimensional intensity distribution in the object plane. For the characterization of commercial X-ray tube types (.e. for advertising or trade) the specific maximum values of annex A should be prefe
12、rred. 2 Normative references This European Standard incorporates by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or
13、revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies. EN 584-1, Non-destructive testing - Industrial radiographic film - Part 7; Classification of
14、 film systems for industrial radiography. EN 12543-1, Non-destructive testing - Characteristics of focal spots in industrial X-ray systems for use in non- destnrctive - testing - Part ?: Scanning method. 3 Terms and definitions For the purposes of this standard, the following definition applies: Foc
15、al spot: the X-ray emitting area on the anode of the X-ray tube as seen from the measuring device EN 12543-11. 4 Test equipment 4.1 The Slit Camera The slit camera shall consist of a block with a slit with the dimensions given in figure I. It shall be made from tungsten or a similiar absorbant mater
16、ial. 8BSI 12-1999 STD.BS1 BS EN 12543-3-ENGL 1777 81 Lb24bb7 08L7981 784 Page 5 EN 12543-3: 1999 Dimensions in millimetre Key 1 symmetry axis Figure 1 - Essential dimensions of the black and slit 4.2 The angle between the beam direction and the axis of the slit symmetry (see figure 2) shall be small
17、er than 3. When deviating from figure 2, the direction of the beam shall be indicated. Alignment and position of the slit camera O BSI 12-1999 Page 6 EN 12543-3: 1999 1 focal spot 2 beam direction 3 maximum deviation of the slit symmetry axis Figure 2 -Alignment of the slit camera The incident face
18、of the slit shall be placed at a distance m from the focal spot so that the variation of the magnification over the length of the actual focal spot does not exceed i 5 % in the beam direction, see figure 3, according to following formulae: n/m=E n/(m+k)20,95 n/(m-p)S 1,05E where E is the magnificati
19、on. n, m, k and p are given in figure 3. O BSI 12-1999 STD-BSI BS EN 12543-3-ENGL 1777 R Lb24bb7 0817783 557 m Page 7 EN 12543-3: I999 1 plane of anode 2 reference plane 3 radiographic film 4 length of the focal spot 5 beam direction 6 incident face of the slit block 7 length of the actual focal spo
20、t Figure 3 - Beam direction, dimensions and planes For the production of a pair of focal spot slit radiographs the slit block shall be orientated so that the length of the slit is normal within f 5“ to each of two directions of evaluation. For measurements over the length of the focal spot, the dire
21、ction of evaluation shall be parallel to the longitudinal axis of the X-ray tube assembly. For measurements over the width of the focal spot, the direction of evaluation shall be normal to the direction of the length evaluation. O BSI 12-1999 STD-BSI BS EN 12543-3-ENGL 1999 I 1b24bb9 0417784 473 Foc
22、al spot size d (mm) 0,l to 2,o 2,o Page 8 EN 12543-3: 1999 Minimum magnification n/m 3: 1 2:l 4.3 The radiographic film shall be placed normal to the beam direction at a distance n from the incident face of the slit diaphragm determined from the appropriate magnification, according to table 1 : Posi
23、tion of the radiographic film Table 1 - Magnification for focal spot slit radiographs 4.4 Film type and density The film 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 radiograph shall be exposed to a diffuse density be
24、tween 1,5 and 23. 4.5 Loading factors The X-ray systems shall be 75 % of the nominal tube voltage, but not more than 200 kV. The X-ray tube current shall be the maximum applicable tube current at the selected systems. 5 Measurement and determination of the focal spot size 5.1 Measurement The radiogr
25、aph shall be evaluated on an illuminator having a uniform luminance level of 2000 dim2 to 3000 cd/m2. It shall be examined visually using a magnifying lens with a built-in graticule with divisions of 0,l mm and a magnification between 5 and 1 O. The focal spot size is determined separately for the l
26、ength and width directions by evaluation of the visible dimensions of the blackened area divided by the selected magnification factor. 5.2 Determination of the focal spot sire Each focal spot size is described by its size I (length) in the direction of the tube axis and its size w (width) across the
27、 tube. The operating parameters of the X-ray tube shall be recorded. NOTE If the tube axis is not defined, then the direction of the electron trajectory is used instead. The larger of these sizes shall be used as the “focal spot sized “ A specification of the focal spot sized on the X-ray tube shall
28、 refer to this standard. If the focal spot size will be certified, the measurement result has to meet the values of EN 12543-1 within an uncertainty off 10 %. Q BSI 12-1999 Page 9 EN 12543-3:1999 Annex A (informative) Preferred values of d for the characterization of X-ray tubes Table A.l - Preferre
29、d values of d in millimetres Additionally to d, the dimensions of I and w can be indicated in the same steps. O BSI 12-1999 BS EN 12543-3:1999 BSI 389 Chiswick High Road London w4 4AL BSI - British Standards Institution BSI is the independent national body responsible for preparing British Standards
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