1、Characteristics of focal spots in industrial X-ray systems for use in non-destructive testing Part 5: Measurement of the effective focal spot size of mini and micro focus X-ray tubes English version of DIN EN 12543-5 ICs 19.100 DIN - EN 12543-5 Zerstrungsfreie Prfung - Charakterisierung von Brennfle
2、cken in Industrie-Rntgenanlagen fr die zerstrungsfreie Prfung - Teil 5: Messung der effektiven Brennfleckgre von Mini- und Mikrofokus- Rntgenrhren European Standard EN 12543-5 : 1999 has the status of a DIN Standard. A comma is used as the decimal marker. National foreword This standard has been pre
3、pared by CEN/TC 138. The responsible German body involved in its preparation was the Normenausschu Materialprfung (Mate- rials Testing Standards Committee), Technical Committee Durchstrahlungsprfung und Strahlenschutz. EN comprises 6 pages. No pari of this standard may be reproduced without the prio
4、r permission of Y Deutsches Institut fr Normung e. V., Berlin. wth Verlag GmbH, D-10772 Berlin, has the exclusive right of sale for German Standards (DIN-Normen). Ref. No. DIN EN 12543-5 : 1999-1 English price group 06 Sales No. 1106 05.00 EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 12543-5
5、 September 1999 ICs 19.1 O0 English version 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 spot size of mini and micro focus X-ray tubes Essais non destructifs - Caractris- tiques des fo
6、yers missifs des tubes radiognes industriels utiliss dans les essais non destructifs - Partie 5: Mesure de la dimension du foyer missif de tubes radiognes mini et micro foyer Rntgenrhren Zerstrungsfreie Prfung - Charakterisierung von Brennflecken in Industrie-Rntgenanlagen fr die zerstrungsfreie Prf
7、ung - Teil 5: Messung der effektiven Brennfleck- gre von Mini- und Mikrofokus- This European Standard was approved by CEN on 1999-08-1 6. CEN members are bound to comply with the CENKENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national
8、 standard without any alteration. Up-to-date lists and bibliographical references concerning such national stand- ards may be obtained on application to the Central Secretariat or to any CEN member. The European Standards exist in three official versions (English, French, German). A version in any o
9、ther language made by translation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, the Czech Republic, Denmark, Finland, France, Germ
10、any, Greece, Iceland, Ireland, Italy, Luxembourg, the Netherlands, Norway, Portugal, Spain, Sweden, Switzerland, and the United Kingdom. CEN European Committee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels O
11、 1999. CEN - All rights of exploitation in any form and by any means reserved worldwide for CEN national members. Ref. No. EN 12543-5 : 1999 E Page 2 EN 12543-5 : 1999 Contents Page Foreword 2 Introduction . 3 1 Scope . 3 2 Normative references , . 3 3Termsanddefinitions 3 4Testmethod 3 5 Measuremen
12、t and determination of the focal spot size 5 Foreword This European Standard 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 by publication of an
13、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 CENKENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Sta
14、ndard: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netheriands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom. In the framework of its scope, Technical Committee CENTTC 138 entrusted CENITC 138NVG 1 “ionizing
15、 Radiation“ with preparing the following standard: 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 spot size of mini and micro focus X-ray tubes. EN 12543-5 is a part of
16、series of European Standards with the same number: the other parts are the following: EN 12543-1, Non-destructive testing - Characteristics of focal spots in industrial X-ray systems for use in non- destructive testing - Part I: Scanning method EN 12543-2, Non-destructive testing - Characteristics o
17、f focal spots in industrial X-ray systems for use in non- destructive testing - Part 2: Pinhole camera radiographic method EN 12543-3, Non-destructive testing - Characteristics of focal spots in industrial X-ray systems for use in non- destructive testing - Part 3: Slit camera radiographic method EN
18、 12543-4, Non-destructive testing - Characteristics of focal spots in industrial X-ray systems for use in non- destructive testing - Part 4: Edge method Page 3 EN 12543-5 : 1999 Introduction In order to cover the different requirements for focal spot size measurement, five different methods are desc
19、ribed 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 sizes are needed, i. e. calibration and image processing purposes. The radiographic methods (EN 12543-2 and EN 12543-3) describe th
20、e traditional techniques and are dedicated for certification purposes and for field application 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 repre- sents a very simple method for field application. In order to cover also t
21、he micro focus systems, a specific method is presented in EN 12543-5. 1 Scope This European standard specifies a method for the measurement of focal spot dimensions within the range of 5 pm to 300 pm of X-ray systems up to and including 225 kV tube voltage, by means of radiographs of sharp edges. Th
22、e image quality and the resolution of X-ray images highly depend on the characteristics of the focal spot. The imaging qualities of the focal spot are based on the two dimensional intensity distribution in the object plane. For certification purposes the radiographic technique is used. NOTE ment may
23、 be poorer. The same procedure can be used at higher kilovoltages by agreement but the accuracy of the measure- 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
24、 in the text and the publications are listed hereafter. For dated references, subsequent amendments to or 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 referre
25、d to applies. EN 584- 1, Non-destructive testing - Industriai radiographic fim - Part 1: Classification of film systems for industrial radiography. 3 Terms and definitions For the purposes of this standard, the following definition applies: Focal spot: the X-ray emitting area on the anode of the X-r
26、ay 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 size by measuring the geometric unsharpness. For this purpose sharp edges are imaged either on a film or by means of a radioscopic device u
27、sing a relatively high geometric magnification. The following equipment is required for the measurement if using a film: - a test object as described below, - films, min. 10 cm x 10 crn without screens, - film cassettes made of low absorbing material (e.g. polyehtylene), - a film holder, - a film pr
28、ocessing unit, - a microdensitometer capable of reading densities of D 2 3,O and having an input diaphragm d, of 10 prn or smaller. Page 4 EN 12543-5 : 1999 The following equipment is required for the measurement if using a radioscopic device: - a test object as described below, - a radioscopic devi
29、ce, e. g. any image intensifier with TV equipment, - an image processing device with the capability of producing linear intensity profiles within the radioscopic image in two directions perpendicular to each other, and with the capability to measure distances. The test object shall be either a cross
30、 wire or a ball consisting of highly absorbing material (e.g. tungsten, tungsten alloy or platinum) having a diameter between 0,9 mm and 1,l mm which has an accuracy of i 0,Ol mm. In case of using wires they shall cross each other of an angle of 90“ f 3“. The wires shall be mounted across a circular
31、 aperture in a stable frame, in such a manner that the crossing point is located in the center of the aperture. In case of using the ball it shall be mounted on a thin polyethylene support or placed into a thin polyethylene envelope. The mounting frame shall be of a size that enables the test object
32、 to be positioned very close to the window of the X-ray tube. Scattering shall be avoided as far as possible. Any use of additional X-ray prefiltering shall be avoided. In case of using a film system the following shall be ensured: The film system shall meet the requirements of film system class C2
33、according to EN 584-1 and shall be packed in low absorption polyethylene cassettes using no screens. 4.2 Selections of distances and exposure time The distance between test object and detector shall enable projective magnification between X 20 and X 100 (see figure l), where smaller focal spots requ
34、ire larger magnifications in the given range. The minimum distance between the test object and the focal spot shall be at least five times the wire or ball diameter. In case of using a cross wire, its plane shall be parallel within I 3“ to both the tube axis and the detector plane. In case of using
35、a film, the exposure time shall result in a background density of the radiograph film of D = 2,5 0,3. If no shutter is used the exposure time shall exceed 30 s. 2 I Projection magnification M = (a + b)/a Key 1 X-ray tube anode 2 test object 3 film plane Figure 1 - Positioning of test object Page 5 E
36、N 12543-5 : 1999 5 5.1 Measurement Line scans shall be produced of the image in length and width direction. If using radiography, this shall be done with a suitable microdensitometer with an aperture of about 10 pm. If using radioscopy, the measurement shall be done using an image processor. From th
37、ese scans the diameters 4 and 0, of the test object in width and length direction shall be measured at 50 Oh of the total image contrast (points B and C), see figure 2. The geometrical magnification is Measurement and determination of the focal spot size 4,w = 4,w f Gal (1 ) where O, is the real dia
38、meter In case of the cross wire both wires have to be measured because of their different magnifications. Then, according to figure 2, the points A and D are obtained at 90 YO of the contrast. From the projection the focal spot sizes I and w are calculated using equation (2) and equation (3): w = (F
39、 i- GH) 1 M, (3) Page 6 EN 12543-5 : 1999 300 I I 3,O III I- IIIIII 1- l t 150 2oo I t - O t- ._ A _. _. E u -50 O 20 40 60 Length X - D Figure 2 - Profile of test object image (Test object: Pt wire 1 mm) 5.2 Deter mi nat ion Each focal spot size is defined by its size / (length) in the direction of
40、 the tube axis and its size w (width) in the perpendicular direction. If the tube axis is not defined, then the direction of the electron trajectory shall be used instead. The larger of these sizes shall be used as the “focal spot size do It is only valid in connection with the used and recorded operating parameters during the measurement.
