1、BRITISH STANDARD Nomdestructive testing - Characteristics of focal spots in industrial X-ray systems for use in non-destructive testing - Part 4: Edge method The European StandardEN 1264341999hasthe status of a Britjsh SM ICs 19.100 BS EN 1254341999 f %. 7- i NO COPYING WTOm BSI PERMiSSION EXCEPT AS
2、 PERMTTED BY COPYRIGHT LAW National foreword This British Standard is the English language version of EN 12543-4: 1999. The UK participation in its preparation was entrusted to Technical Committee WEW46, Nondestructive testing, which has the responsibility to: - aid enquirers to understand the text;
3、 - present to the responsible European committee any enquiries on the - monitor related international and European developments and promulgate interpretation, or proposals for change, and keep the UK interests informed; them in the UK. A list of organizations represented on this committee can be obt
4、ained on request to its secretary. Cross-references The British Standards which implement intemational or European publications referred to in this document may be found in the BSI standards Catalogue under the section entitled “Inkmational Standards Correspondence Index”, or by using the “Find” fac
5、ility of the BSI Standards Electronic Catalogue. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal oblig
6、ations. Summary of pages This document comprises a front cover, an inside front cover, the EN title page, pages 2 to 9 and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued. This British Standard, having been prepared under the direction of
7、 the Engineering Sector Committee, was published under the authority of the Standards Committee and comes into effect on 15 December 1999 Amendments issued since publication -No.- comments 0 BSI 12-1999 ISBN O 580 35170 X EUROPEAN STANDARD EN 12543-4 NORME EUROPENNE EUROPISCHE NORM September 1999 IC
8、s 19.100 English version Non-destructive testing - Characteristics of focal spots in industrial X-ray systems for use in non-destructive testing - Part 4: Edge method Essais non destructifs - Caractristiques des foyers 6missifs des tubes radiognes industriels utiliss dans les essais non destructifs
9、- Partie 4: Mbthode par effet de bord Zersiningsfreie Prfung - Charakterisierung von Brennflecken in Industrie-Rntgenanlagen fr die zerstningsfreie Prfung - Teil 4: Kantenverahren This European Standard was approved by CEN on 16 August 1999. CEN members are bound to comply with the CENICENELEC inter
10、nal Regulations which stipulate !he conditions for giving this Europeen Standard the status of a national standard Without any alteration. Uptodate llsts and bibliographicai references concerning ah national standards may be obtained on application to the Central Secretariat or to any CW member. Thi
11、s European Standard exists in three official versions (English, French, German). A version in any other language made by trmslation under the responsibility of a CEN member into its orni language and notified to the Central Secretariat has the same status as he official versions. CEN members are the
12、 naibnal standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Noway, Portugal, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMIITEE FOR STANDARDIZATION EUROPAISCHES KOMITEE FOR NORMUNG COMITB E
13、UROPEEN DE NORMALISATION Central Seereariit: rue da Sassart, 36 81050 Brussels O 1999 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 125434:1999 E Page 2 EN 1 2543-4: 1999 Contents Page Foreword . Introduction . 1 Scope . 2 Normat
14、ive references 3 Terms and definitions 4 Test method . 5 Measurement and determination of the focal spot size . Annex A (informative) Data analysis . O BSI 12-1999 Page 3 EN 125434 1999 Foreword This European Standard has been prepared by Technical Committee CEWC 138, Nondestructive testing, the Sec
15、retariat of which is held by AFNOR. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by March 2000, and conflicting national standards shall be withdrawn at the latest by March 2000. According to the
16、CEWENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Swede
17、n, Switzerland and the United Kingdom. In the framework of its scope, Technical Committee CEWC 138 entrusted CENTTC 13WG I “Ionizing Radiation“ with preparing the following standard: EN 125434, NondesWve testing - Characteristics of focal spots in indushial X-ray systems for us8 in non- destructive
18、testing - Part 4: Edge method EN 12543-4 is a part of series of European Standards with the same number; the other Parts are the following: EN 12543-1, Nondestructive testing - Characterisks of focal spots in industrial X-ray systems for use in non- esttuctive testing - Patt I: Scanning metW. EN 125
19、43-2, Non-destnrdive testing - Chamcteriscs of focal spots in indushial X-ray systems for use in non- destructive testing - Patt 2: Pinhole camera radiographic method. EN 12543-3, Non-tiestructive testing - Characteristics of Ibcal spots in industrial X-ray systems for use in non- destructive testin
20、g - Part 3: Slit camera radiographic method EN 12543-5, Nondeshtive testing - Characteristics of focal spots in indusial X-ray systems for use in non- destructive testing - Part 5: Measurement of the effectne focal spot size of mini and micro focus X-ray tubes. Q BSI 12-1999 Page 4 EN I 2543-4: I999
21、 Introduction 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 applications where quantitative values for the intensity distribution and spot size are
22、 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 applications up to 200 kV. Where no pinhole or slit cameras are available in the field, the ed
23、ge method (EN 125434) 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 Standard specifies the checking of focal spot dimensions above 0,5 mrn of X-ray systems
24、up to and including 500 kV tube voltage, by means of radiographs of sharp edges. The image quality and the resolution of X-ray images depend highly on the characteristics of the focal spot. The imaging qualities of a focal spot are based on the two dimensional intensity distribution in the object pl
25、ane. The edge method is especially useful for the checking of focal spots under field conditions in order to find changes of the focal spot. It cannot be used for an absolute measurement of the focal spot. For absolute measurements the method according to annex A is applied. 2 Normative References T
26、his 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 revisions of any of these publ
27、ications 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 12543-1, Non-destructive testing - Characteristics of focal spots in industrial X-ray systems for use in non- destructi
28、ve testing - Part 7: Scanning method. EN 584-1, Non-desttuctive testing - Industrial radiographic film - Part 1: Classification of film systems for industrial radiography. EN 25580, Non-destructive testing - Industrial radiographic illuminators - Minimum reguirements (IS0 5580: 1 985). 3 Terms and d
29、efinitions For the purposes of this standard, the following definition applies: focal 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 method 4.1 Principle and equipment This method is based on indirect measurement of the focal spot s
30、ize by measuring the geometric unsharpness. For this purpose a sharp edge is imaged on a film using a relatively high geometric magnification. O BSI 12-1 999 Page 5 EN 12543-4: 1999 The fdlowing equipment is required for the measurement: - - - - - - - - a film processsing unit, fitms with a minimum
31、length of 24 cm without screens, film cassettes made of thin plastic material or aluminium, lead letters L and W, a collimating diaphragm in front of the tube window compatible with the size of the film, a steel cylinder or a thick walled pipe of 50 mm to 100 mm diameter and about 100 mm length, a s
32、upport (tripod) to carry the steel cylinder, a sheet of lead approximately 200 mm x 100 mm, 1 mm thick or thicker, - - an illuminator with a uniform and constant brightness according to EN 25580, an optical densitometer capable of reading densities of D 2 3,O. The densitometer shall permit contrast
33、measurements of A D = 0,Ol. Its input diaphragm 4 shall be 2 mm or smaller. A cylindrical surface is placed as an edge in the beam direction (figure 1). An ordinary steel cylinder or a thick waled pipe with a diameter of 50 mm to 100 mm and with a length of about 1 O0 mm is used for this purpose. A
34、sheet of lead with a thickness of 1 mm or larger is to be wrapped around the cylinder. Scattering shall be avoided as far as possible. A collimating diaphragm with an opening compatible to the size of the film shal be placed in front of the tube window. Any use of additional X-ray prefiltering shall
35、 be avoided. For the characterization of the focal spot its size shall be measured in two perpendicular directions. The two measurements shall be made so that: I) the tube axis and cylinder edge shall be perpendicular for one measurement, lead letter L on film, and 2) the tube axis and cylinder edge
36、 shall be parallel to each other for the other measurement, lead letter W on film. The image of the lead letters shall be in the dark part of the film. The film shall be positioned aiways with its longer dimension perpendicular to the cylinder axis. As a result the unsharp image of the edge shall be
37、 crosswise on the film in either case. 4.2 Referring to figure 1, the distances fand s represent respectively the source to edge and the edge to film distances and dc is aie diameter of the steel cylinder including the lead covering. An estimate for the relation between fand s may be derived from a
38、given nominal value of the focal spot size. The relation SB shall be larger than or equal to ten times the diameter of the density meter input diaphragm 4 divided by the focal spot size d, provided by the manufacturer (see equationl). Selection of distances and exposure time NOTE be decreased to 1 m
39、m or below. If the distance s gets impractically long, the diameter of the densitometer input diaphragm di should The ratio f/d, shall be larger than 5. As an example a film to focus distance (f + s) of about 2 meters is appropriate for a 300 kV5 mA X-ray tube. Q BSI 12-1999 STD-BSI BS EN L2543-4-EN
40、GL 1977 E Lb24Lb7 0820Ub8 895 M 1 2 3 f 5 T Page 6 EN 125434 I 999 1 O hl AI .u I Dimensions in millimetres 1 source/focal spot 2 edge 3 Imm lead sheet 4 film Figure 1 -Setup for measuring the focal spot size If the nominal focal spot size is not known, the relation between s and f has to be found e
41、xperimentally by a preliminary determination of the focal spot size using the present edge method. The part of the film completely exposed shall have a density ofD = 2,5 f 0,3. The exposure time shall exceed 30 s. 5 Measurement and determination of the focal spot size 5.1 Measurement Subsequently, t
42、he density profile on the processed film (figure 2) is evaluated in order to measureu,. If one considers the film to be divided into three zones of differing density, namely the light zone, the transition zone and the dark zone, then the density profiles in the light and the dark zones shall be as u
43、niform as possible, .e. no sharp fluctuations. If the density variation over the length of either zone (.e. along the length of the film) is more than 2 YO of the total contrast, then it is necessary to check the protection against scattered radiation and to repeat the exposure. The geometric unshar
44、pness ug will be determined in terms of the contrast which is the difference in density (O) measured at the darkest and the brightest region on the film. If a hand held density meter is used, the density shall be measured at a fixed point on the illuminator, where the zero adjustment of the densitom
45、eter was made. In this case, it is necessary to slide the film instead of moving the densitometer. The zero adjustment of the densitometer shall be checked before and after the measurement. In case of deviations the measurement has to be repeated. First the total contrast between dark and bright zon
46、e is measured. Then the two points of 5 % and 95 % of the contrast are marked on the film. The distance between these points is the geometric unsharpnessu,. In order to illustrate the procedure for the measurement of the geometric unsharpness, a density profile is shown in figure 2, and the points w
47、ith 5 YO and 95 YO of the total contrast are projected on the abscissa. The OBSI 12-1999 Page 7 EN 12543-4: 1999 length of this projection is udor u, dependent on the orientation of the tube axis. The focal spot size shall be determined according to the following equations: I = ug#s (2) w = ugwfls (
48、3) where I focal spot length w focal spot width f distance between focal spot and edge (fgure 1), s edge to film distance. T .- cn c Q) cl o o .- U a O Figure 2 - Example for a density profile on the film and its evaluation 5.2 betermination Each focal spot size is defined by its size I (length) in
49、the direction of the tube axis and its size w (width) in the perpendicular direction. The larga of these sizes shal be used as the “focal spot size d “. If the larger of the values I or w exceeds the value dn given within the specification of aie tube, a more precise method for the measurement of the focal spot size shall be applied before further use of the tube (see for example Annex A). 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 STD-BSI BS EN 12543-4-ENGL 1777
