1、| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BRITISH STANDARD BS EN 12679:2000 The Euro
2、pean Standard EN 12679:1999 has the status of a British Standard ICS 19.100 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Non-destructive testing Determination of the size of industrial radiographic sources Radiographic methodThis British Standard, having been prepared under
3、 the direction of the Engineering Sector Committee, was published under the authority of the Standards Committee and comes into effect on 15 January 2000 BSI 01-2000 ISBN 0 580 35225 0 BS EN 12679:2000 Amendments issued since publication Amd. No. Date Comments National foreword This British Standard
4、 is the English language version of EN 12679:1999. The UK participation in its preparation was entrusted to Technical Committee WEE/46, Non-destructive testing, which has the responsibility to: aid enquirers to understand the text; present to the responsible European committee any enquiries on the i
5、nterpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards
6、 which implement international or European publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. A British Standard do
7、es 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 obligations. Summary of pages This document comprises a front cover, an ins
8、ide front cover, the EN title page, pages 2 to 4, an inside back cover and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued.CEN European Committee for Standardization Comite Europe en de Normalisation Europa isches Komitee fu r Normung Cen
9、tral Secretariat: rue de Stassart 36, B-1050 Brussels 1999 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 12679:1999 E EUROPEAN STANDARD EN 12679 NORME EUROPE ENNE EUROPA ISCHE NORM October 1999 ICS 19.100 English version Non-dest
10、ructive testing Determination of the size of industrial radiographic sources Radiographic method Essais non destructifs De termination des dimensions des sources de radiographie industrielle Me thode par radiographie Zersto rungsfreie Pru fung Bestimmung der Strahlergro en von industriell genutzten
11、Radio-Nukliden Durchstrahlungsverfahren This European Standard was approved by CEN on 3 September 1999. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
12、 Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
13、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, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy,
14、Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.Page 2 EN 12679:1999 BSI 01-2000 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 sh
15、all be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by April 2000, and conflicting national standards shall be withdrawn at the latest by April 2000. According to the CEN/CENELEC Internal Regulations, the national standards orga
16、nizations 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 framework of
17、its scope, Technical Committee CEN/TC 138 entrusted CEN/TC 138/WG 1, Ionizing radiations, with preparing the following standard: EN 12679, Non-destructive testing Determination of the size of industrial radiographic sources Radiographic method. Contents Page Foreword 2 1 Scope 3 2 Definitions 3 3 Te
18、st equipment (film technique) 3 4 Test equipment (real time technique) 3 5 Measurement and determination of source size d 3 6 Test report 4Page 3 EN 12679:1999 BSI 01-2000 1 Scope This standard specifies the determination of the size of gamma radiographic sources of 0,5 mm or greater, made from the
19、radionuclides Iridium 192, Ytterbium 169, Selenium 75, or Cobalt 60, by a method of radiography with X-rays. The source size of a gamma radiography source is an important factor which affects the image quality of gamma ray images. The source size is determined with an accuracy of 10 % or 0,1 mm max.
20、 This standard can be used for other radionuclides after validation. Warning. Exposure of any part of the human body to X-rays or gamma-rays can be highly injurious to health. Wherever X-ray equipment or radioactive sources are in use, it is essential to apply the appropriate legal requirements. 2 D
21、efinitions For the purposes of this standard, the following definition applies. 2.1 source size d size of the source of radiation 3 Test equipment (film technique) 3.1 Test alignment The X-ray equipment has to be placed at a minimum filmfocus-distance of 700 mm. The film shall be placed perpendicula
22、r to the axis of the X-ray beam; the gamma source shall be placed on the axis between the X-ray source and the film; the gamma source to film distance b shall be 10 % to 20 % of the X-ray source to film distance a + b; see Figure 1. magnifying factor m= d 9 d a + b a Key 1 X-ray tube 2 gamma source:
23、 size d 3 image of gamma source: projected size d9 4 film Figure 1 Test alignment 3.2 Test parameters An image of radiation source that has sufficient contrast to be easily measured shall be obtained. 3.3 Test application The X-rays should be switched on immediately after the arrival of the gamma so
24、urce in the exposure position and switched off again simultaneously with the gamma source leaving the exposure position. The source movement time should be minimized to reduce fogging of the film. 4 Test equipment (real time technique) The test should be performed with a real time radioscopic equipm
25、ent including X-ray source, image detector and an image processing computer which is at least able to perform image integration and analysis of source dimensions. 4.1 Test alignment The image detector shall be placed perpendicular to the axis of the X-ray beam. For the test the gamma source shall be
26、 placed at a position where it is in the centre of the beam during the exposure. The geometric magnification factor given by the alignment of X-ray source, gamma source and detector shall be high enough to ensure that a spatial resolution of 0,1 mm is obtained. The X-ray source shall have a focus wh
27、ich is small enough to fulfil these conditions. 4.2 Test parameters The gamma source is brought into the test position and shall not be moved during the measurement. Image integration for noise reduction is recommended. The scale of the inspection system shall be so adjusted that 1 mm of the object
28、is represented by at least 20 pixels. A control object with well defined dimensions (e.g. a tungsten cylinder) shall be depicted in the vicinity of the gamma source for calibration purposes. Calibration and analysis of source dimensions shall be performed using the corresponding functions of the ima
29、ge processing computer. 5 Measurement and determination of source size d 5.1 Measurement The radiograph (see clause 3) shall be examined visually on a film illuminator using a magnifying lens with a built-in graticule with divisions of 0,1 mm and a magnification between 5 and 10. The magnifying fact
30、or m according to Figure 1 has to be taken into account for calculation of the actual dimension from the measured values. The video print (see clause 4) shows the source size of the radiographic source with a certain magnifying factor. The visual examination shall consider a reference dimension as t
31、he diameter of the control object (e.g. a tungsten cylinder) to determine the overall magnifying factor and the real dimensions of the source.Page 4 EN 12679:1999 BSI 01-2000 5.2 Determination Each source size is described by its dimension (length) in the direction of the axis of the source holder a
32、nd the dimension w (width) in the perpendicular direction. The larger of these size values/or w shall be used as the “source size d”. 6 Test report A test report shall contain at least the following information: a) reference to this standard; b) identification of source and holder, activity; c) foca
33、l spot size of the X-ray equipment, in millimetres; d) magnification factor used (see Figure 1); e) technique used; f) parameters of X-ray equipment; g) film-screen-system or radioscopic system, respectively; h) distances a, b and exposure time t; i) source size d, in millimetres; j) date of the mea
34、surement; k) name of test organization; l) signature of tester.blankBS EN 12679:2000 BSI 389 Chiswick High Road London W4 4AL | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
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