1、DEUTSCHE NORM December 1999 Characteristics of focal spots in industrial X-ray systems for use in non-destructive testing Part 1 : Scanning method English version of DIN EN 12543-1 DIN - EN 12543-1 ICs 19.100 Zerstrungsfreie Prfung - Charakterisierung von Brennflecken in Industrie-Rntgenanlagen fr d
2、ie zerstrungsfreie Prfung - Teil 1 : Scan-Verfahren European Standard EN 12543-1 : 1999 has the status of a DIN Standard. A comma is used as the decimal marker. National foreword This standard has been prepared by CEN/TC 138. The responsible German body involved in its preparation was the Normenauss
3、chu Materialprfung (Mate- rials Testing Standards Committee), Technical Committee Durchstrahlungsprfung und Strahlenschutz. EN comprises 8 pages. No pari of this standard may be reproduced without the prior permission of Y Deutsches Institut fr Normung e. V., Berlin. wth Verlag GmbH, D-10772 Berlin,
4、 has the exclusive right of sale for German Standards (DIN-Normen). Ref. No. DIN EN 12543-1 : 1999-1 English price group O7 Sales No. 1107 05.00 EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 12543-1 September 1999 ICs 19.1 O0 English version Non-destructive testing Characteristics of focal sp
5、ots in industrial X-ray systems for use in non-destructive testing Part 1 : Scanning method Essais non destructifs - Caractris- tiques des foyers missifs des tubes radiognes industriels utiliss dans les essais non destructifs - Partie 1 : Mthode par balayage Scan-Verfahren Zerstrungsfreie Prfung - C
6、harakterisierung von Brennflecken in Industrie-Rntgenanlagen fr die zerstrungsfreie Prfung - Teil 1 : 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 t
7、he status of a national 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, Germ
8、an). A version in any other 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
9、, Finland, France, Germany, 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 Stassar
10、t 36, B-1050 Brussels O 1999. CEN - All rights of exploitation in any form and by any means reserved worldwide for CEN national members. Ref. No. EN 12543-1 : 1999 E Page 2 EN 12543-1 : 1999 Contents Page Foreword 2 Introduction 3 1 Scope 3 2 Terms and definitions . 3 3Testmethod 3 4 Measurement and
11、 determination of the focal spot size 4 Annex A (informative) Preferred values of dfor the characterization of X-ray tube types . 8 Foreword This European Standard has been prepared by Technical Committee CENKC 138 “Non-destructive testing“, the secretariat of which is held by AFNOR. This European S
12、tandard 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 CENLENELEC Internal Regulations, the national stand
13、ards 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, Sweden, Switzerland and the United Kingdom. In the fram
14、ework of its scope, Technical Committee CENITC 138 entrusted CENRC 138MIG 1 “Ionizing Radiation“ with preparing the following standard: 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 12
15、543-1 is a part of series of European Standards with the same number; the other parts are the following: 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 12543-3, Non-d
16、estructive testing - Characteristics of focal spots in industrial X-ray systems for use in non- destructive testing - Part 3: Slit camera radiographic method EN 12543-4, Non-destructive testing - Characteristics of focal spots in industrial X-ray systems for use in non-destructive testing - fart 4:
17、Edge method EN 12543-5, Non-destructive testing - Characteristics of focal spots in industrial X-ray systems for use in non-destructive testing - fart 5: Measurement of the effective focal spot size of mini and micro focus X-ray tubes. Page 3 EN 12543-1 : 1999 d mm 0.1 to 0,2 0,2 to 0,3 0,3 to 1,O l
18、,o 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 a
19、re 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
20、edge method (EN 12543-4) may be applied. It repre- sents 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 measurement of focal spot dimensions of industrial X-ray s
21、ystems up to and including 500 kV tube voltage. It describes a method of direct mechanical scanning of focal spots above 0,l mm with a highly collimated receiver. The image quality and the resolution of X-ray images depend highly on the characteristics of the focal spot, in particular the size and t
22、he two-dimensional intensity distribution. For the characterization of commercial X-ray tube types (.e. for advertising or trade) the specific maximum values given in annex A should be preferred. h Il0 pm 2 15 pm I 20 pm 2 0,025 x d 2 Terms and definitions For the purposes of this standard, the foll
23、owing definition applies: Focal spot: the X-ray emitting area on the anode of the X-ray tube as seen from the measuring device. 3 Test method 3.1 Principle and equipment This clause deals with the production of focal spot scans to be used for the determination of the focal spot intensity distributio
24、n and dimensions. The coarsely precollimated central beam of the X-ray tube is measured by a scintillation counter through a double slit collimator. The collimator forms a hole with the dimensions hx h. The width hdepends on the spot size dand shall be selected corresponding to table 1: Table - 1 Co
25、llimator hole dimension h in relation to the focal spot size d The precollimator, double slit collimator and radiation detector shall be mounted as one unit on a x-y scanning table. The output signal of the detector shall be registered by a data acquisition facility (figures 1, 2). The data acquisit
26、ion shall be well synchronized with the x-y scanning table. The data acquisition is done in the way that at certain step widths a line scan is registered (figure 3). The step width depends on the required resolution, but it shall not exceed 0,l mm. The precollimator shall be made of lead containing
27、a hole of approximately 5 mm diameter. The thickness depends on the maximum X-ray voltage. It shall correspond to a hundredth value layer at least. Page 4 EN 12543-1 : 1999 The measuring collimator is made of two perpendicular slits, see figure 4. Each slit is formed by two metal blocks with the thi
28、ckness L facing each other and kept at a distance h by spacers at the edges. The thickness L shall be L 20 x (da) x h (1) where a is the distance between the focal spot and the collimator surface (source side) and dis the focal spot size to be measured. The minimum thickness i of the collimators sha
29、ll be defined such that the measured signal intensity through the hole shall be at least 100 times larger than the background noise due to the penetration of the collimator material. The roughness Ra of the slit surfaces shall be better than 2 pm, and the flatness and the parallelism better than M5.
30、 The material of the metal blocks shall be tungsten or another similar absorbant material. The radiation detector shall work in the X-ray voltage range between 10 kV and the nominal voltage of the tube to be measured. At the brightest parts of the intensity distribution of the spot the output signal
31、 shall have a signal-to- noise ratio of at least 40 dB, and the output signal shall follow the radiation intensity linearly. Data acquisition and data processing shall be.stable to at least 1 I-% over the measuring time.-.The x-y scanning table shall be capable of resolving and reproducing at least
32、hi2. 3.2 Alignments One of the axes of the x-y scanning table shall be to +. 3“ parallel to the axis of the tube assembly. The x-y scanning table plane shall be to 2 3“ perpendicular to the main beam of the tube assembly. The distance between the focal spot and the collimators shall be as small as p
33、racticable. When deviating from figure 1 the direction of the main beam shall be indicated. NOTE 3.3 Graphic software The graphic software shall offer the possibility of an isodose contour plot (figure 6). Plots according to figures 3 and 5 can give additional information about the radiation intensi
34、ty distribution, which may be useful for computer tomography and image processing. If the tube axis is not defined, then the direction of the electron trajectory is used instead. 4 4.1 Measurement The dimensions of the focal spot shall be determined from the isodose contour plot (see figure 6) at 10
35、 % of the maximum intensity. 4.2 Each focal spot size is described by its size /(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 The larger of these sizes (/ or w) shall be used as the “focal spot siz
36、e d“. A specification of the focal spot size don the X-ray tube shall refer to this standard. Measurement and determination of the focal spot size Determination of the focal spot size Page 5 EN 12543-1 : 1999 5 I Key I - 1 personal computer and data acquisition unit 2 scintilation counter 3 double s
37、lit collimator (h x h x 2 ) 4 precollimator 5 X-ray tube 6 scattered radiation protection Figure 1 - Measuring facility for radiometric determination of the focal spot size (scheme) Key 1 X-ray tube 2 scan directions 2 Lead rZa Tungsten Figure 2 - Measuring facility for radiometric determination of
38、the focal spot size (example) Page 6 EN 12543-1 : 1999 l,4 1 t O Key 1 slit 2 foil (steel) 3 hidden slit Dose rate - 02 03 mm 0,4 DistanceX - Figure 3 - Line scans of a focal spot 2 h c Figure 4 - Double slit collimator (from above) Page 7 EN 12543-1 : 1999 Figure 5 - Graphical interpretation of the
39、 intensity distribution of focal spot scans X- Figure 6 - Isodose contour plot Page 8 EN 12543-1 : 1999 Annex A (informative) Preferred values of d for the characterization of X-ray tubes Table A.l - Preferred values of din millimetres Additionally to a! the dimensions of fand wcan be indicated in the same steps.
