STD BSI BS EN 12544 2 ENGL 2ÖUU 81 L b 2 4 b b ï 085448b 8T8 BRITISH STANDARD Non destructive testing Measurement and evaluation of the X ray tube voltage Part 2 Constancy check by the thick filter me[.]
STD.BSI B S EN 12544-2-ENGL 2ÖUU 81 L b b b ï 4 b 8T8 BS EN 12544-2:ZOOO BRITISH STANDARD Non-destructive testing - Measurement and evaluation of the X-ray tube voltage Part 2: Constancy check by the thick filter method The European Standard EN 12544-2:2000 has the status of a British Standard ICs 19.100 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMïìTED BY COPYRIGHT LAW ```,,,-`-`,,`,,`,`,,` - Copyright European Committee for Standardization Provided by IHS under license with CEN No reproduction or networking permitted without license from IHS Not for Resale National foreword This British Standard is the official English language version of EN 1254422000 The UK participation in its preparation was entnisted to Technical Committee WEW46, Nondestructive testing, which has the responsibility to: - aid enquirers to understand the text; - present to the responsible European committee any enquiries on the interpretation,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 organizationsrepresented on this committee can be obtained on request to its secretary Cross-references The British Standards 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 does not purport to include ail 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 inside front cover, the EN title page, pages to and a back cover The BSI copyright notice displayed in this document indicates when the document was last issued direction of the Engineering Sector Committee, was published under the authority of the Standards Committee and comes into effect on 15 June 2000 AmdNo Date Comments O BSI 06-2000 ISBN O 580 34178 X ```,,,-`-`,,`,,`,`,,` - Copyright European Committee for Standardization Provided by IHS under license with CEN No reproduction or networking permitted without license from IHS Not for Resale ~ STD*BSI BS EN L25q4-2-ENGL 0 L b V b b OBS'i'idd b70 EN 125442 EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM February 2000 _ ICs 19.100 English version Non-destructive testing - Measurement and evaluation of the X-ray tube voltage - Part 2: Constancy check by the thick filter method ```,,,-`-`,,`,,`,`,,` - Zerstörungsfreie Prüfung - Messung und Auswertung der Röntgenröhrenspannung- Teil 2: Konstanzprüfungmit dem Dickfilter-Verfahren Essais non destructifs - Mesurage et évaluation de la tension des tubes radiogènes- Partie 2: Contrôle de la constance selon la méthode du filtre épais This European Standard was approved by CEN on 24 December 1999 CEN members are bound to comply with the CENKENELEC Internal Regulationswhich stipulate the conditions for giving this Europsan Standard the status of a national standard without any alteration Up-to-date lists and bibliographical references concerning ruch 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 traislation under the responsibilityof a CEN member into its own language and notified to the Central Secretariat has the same status as h e official versions CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom EUROPEAN COMMITTEE FOR STANDARDIZATION COMITÉ EUROPÉEN D E NORMALISATION E U R O P Ä I S C H E S KOMITEE F Ü R N O R M U N G Central Secretariat: rue de Stassart, 36 O 2000 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members Copyright European Committee for Standardization Provided by IHS under license with CEN No reproduction or networking permitted without license from IHS Not for Resale B-1050Brussels Ref No EN 12544-2:2000 E Page EN 12544-2:2000 Contents Foreword Introduction Scope Principle and equipment Measurement Test report Annex A (informative) Example for application O BSI 06-2000 ```,,,-`-`,,`,,`,`,,` - Copyright European Committee for Standardization Provided by IHS under license with CEN No reproduction or networking permitted without license from IHS Not for Resale ~ S T D - B S I B S EN 4 - - E N G L 2000 L b b b 085'1470 2 Page EN 12544-212000 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 identical text or by endorsement, at the latest by August 2000, and conflicting national standards shall be withdrawn at the latest by August 2000 According to the CENKENELEC 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, Sweden, Switzerland and the United Kingdom In the framework of its scope, Technical Committee CEN/TC 138 entrusted CENTTC 138MIG "Ionizing Radiation" with preparing the following standard: EN 12544-2, Non-destructive testing - Measuremenent and evaluation of the X-ray tube voltage - Part 2: Constancy check by the thick filter method EN 12544-2 is a pari of series of European Standards; the other parts are the following: EN 12544-1, Non-destructive testing - Measurement and evaluation of the X-ray tube voltage - Part 1: Voltage divider method EN 12544-3, Non-destructive testing - Measurement and evaluation of the X-ray tube voltage - Part 3: Spectrometric method O BSI 06-2000 Copyright European Committee for Standardization Provided by IHS under license with CEN No reproduction or networking permitted without license from IHS Not for Resale Page EN 12544-2:2000 Introduction In order to cover the different requirements for the measurement of the X-ray tube voltage, three different methods are described in EN 12544-1 to EN 12544-3 The voltage divider method (EN 12544-1) enables a direct and absolute measurement of the average high voltage of constant potential X-ray systems on the secondary side of the high voltage generator The thick filter method (EN 12544-2) describes a constancy check This method is recommended for the regular stability check of an X-ray system The spectrometric method (EN 12544-3) is a procedure for non-invasivemeasurement of the X-ray tube voltage using the energy spectrum of the X-rays This method can be applied for all X-ray systems and shall be applied whenever the voltage divider method is not applicable, e.g in case of tank units where it is not possible to connect the voltage divider device O BSI 06-2000 ```,,,-`-`,,`,,`,`,,` - Copyright European Committee for Standardization Provided by IHS under license with CEN No reproduction or networking permitted without license from IHS Not for Resale ~ ~ SÏD-BSI BS EN L25qq-Z-ENGL 0 Lb2'ibbS 0854472 O T L ```,,,-`-`,,`,,`,`,,` - Page EN 12544-2:2000 Scope This standard specifies a constancy check of a X-ray system where mainly the X-ray voltage is checked and also the tube current and the constitution of the target which can be changing due to ageing of the tube The thick filter method is based on a measurement of the dose rate behind a defined thick filter using defined distances between the X-ray tube, the filter and the measuring device This method is very sensitive to changes of the voltage, but it does not provide an absolute value for the X-ray tube voltage Therefore, a reference value is needed and, it is recommended to find this reference, for example, within the acceptance test of the system The thick filter method is a rather simple technique and may be applied by the operator of an X-ray system to perform regularly a constancy check of the system The method can also be applied for consistency checks after changing components which may affect the X-ray tube voltage This method can be applied for all types of X-ray systems, ¡.e for constant potential, half wave and impulse wave generators with a tube current larger than mA Principle and equipment The equipment to be used includes the following components, see Figure 1: - the X-ray system; - a specified collimator; - a specified filter; - suitable dose meter or dose rate meter; - a film for the prove of good collimation and dose meter or dose rate meter adjustment X-raytube collimator thickfilter lead shield film dosemeter Figure - Setup of the thick filter method O BSI 06-2000 Copyright European Committee for Standardization Provided by IHS under license with CEN No reproduction or networking permitted without license from IHS Not for Resale STD.BS1 B S E N L254q-Z-ENGL 2000 E L b b b 4 T38 Page EN 12544-2:2000 It is possible to apply any type of filter and distances Two aspects are important: - To obtain reproducible values, the collimator, the filter and the dose rate meter shall be identical and, the focus to filter distance il2and the focus to dose rate meter distance D, shall be fixed for the reference and all subsequent measurements The filter material and thickness shall be selected according to Figure - The long term stability shall be times better than the tolerance of the measured values A regular stability check of the dose rate meter, using a radioactive source, is necessary - The device shall have adequate measuring ranges - The exposure time shall be selected to obtain values between 50 % and 100 % of the scale Three or more measurements shall be taken and the results shall be averaged The diameter of the selected collimator shall be as small as possible The area of homogeneous radiation intensity at the dose meter or dose rate meter shall be equal or less then times of the size of the detection chamber of the dose meter This shall be proven with a film exposure due to the requirement of exact adjustment This radiograph marked with the date of measurement may be used for documentation Figure shows a typical radiograph of a dose meter which is well adjusted corresponding to Figure NOTE The results of the measurement arrangement are reliable if it provides the same value in horizontal and vertical adjustment Using the thick filter method, the measured values will change approximately to 10 times faster (leverage factor) than the X-ray voltage changes That means for example that % of the X-ray tube voltage change corresponds to 25 % to 50 % of the measured dose rate n E €’ U a, IA v) cn c Y o c -I E E’ t- -S Tube Voltage [kV] Figure - Minimum filter thickness values O BSI 06-2000 Copyright European Committee for Standardization Provided by IHS under license with CEN No reproduction or networking permitted without license from IHS Not for Resale ```,,,-`-`,,`,,`,`,,` - The requirements concerning the dose meter or dose rate meter are: S T D - B S I BS EN 4 - - E N G L 0 H L b b b 0854474 774 H Page EN 12544-2:2000 Figure 3 - Radiograph of the well-adjusted dose meter corresponding to Figure Measurement In order to carry out the constancy check of an X-ray system or the consistency check of an X-ray system to compare different components the dose rate is measured using a filter as given in Figure or thicker 3.1 Leverage factor For the first application of the thick filter method the leverage factor i , shall be determined corresponding to the selected setup The dose value shall be measured at 100 % (boo) and at 95 % (Dgs)of the test voltage NOTE The leverage factor should be adjusted between and This is a compromise which considers limitations in exposure time A high leverage factor is recommended for high accuracy of the method The leverage factor is calculated by equation (1) 3.2 Constancy check The constancy test of the tube shall be repeated regularly at the given voltage The arrangement corresponding to Figure shall be used with the same collimator, thick filter (thickness and material) and the same calibrated dose meter for the constancy check The constancy of the tube voltage is confirmed if the measured dose value or dose rate value has been reproduced within the required tolerance T (in %)which is calcualted by equation (2) Within the reference measurement all essential parameters (distances D1 and D2, filter material and thickness, type of dose meter or dose rate meter) shall be documented The arrangement shall be identical for all subsequent measurements An example is given in Annex A ```,,,-`-`,,`,,`,`,,` - O BSI 06-2000 Copyright European Committee for Standardization Provided by IHS under license with CEN No reproduction or networking permitted without license from IHS Not for Resale S T D - B S I BS EN 12544-2-ENGL 2000 l b b b ỵ 0854495 800 I Page EN 12544-2:2000 Test report The test report of the measurements shall contain at least the following information: reference to this standard; X-ray system, type and fabrication number; the X-ray parameters: voltage (kv), current (mA) and the selected focus size, preferably the nomimal voltage and the maximum current; type and size of collimator; filter type and thickness, preferably with identification number; dose rate meter, or dose meter, also with identificationnumber; focus to filter distance; focus to dose rate meter distance; drawing of the setup if it deviates from Figure 1; the measured value and the measured leverage factor; the date of the measurement; the deviation from the reference value; name and signature of operator O BSI 06-2000 ```,,,-`-`,,`,,`,`,,` - Copyright European Committee for Standardization Provided by IHS under license with CEN No reproduction or networking permitted without license from IHS Not for Resale Page EN 12544-2:2000 Annex A (informative) Example for application The usage of this standard needs exact adjustment and shielding It is designed for the application of inexpensive equipment Some reference values are given for orientation of users in Table A.l Due to deviations in the adjustment as well as the equipment, considerable differences to the given data are possible The applied X-ray tube was of the constant potentialtype An usual pen-type dose meter was used for the measurements of the dose values The absolute accuracy of the dose meter read out is expected to be not better than 20 % Nevertheless, the final accuracy amounts to about % if a leverage factor of 6,6 is presupposed Table A.l Tube voltage mm mm - Parameter for thick filter method Collimator diameter Thick filter D95 mSv mSv Exposure mAmin L, EXAMPLE For a constancy check at 200 kV and the conditions described above (Table A.l) the Poovalue should be always obtained between l,l mSv and 2,l mSv to prove a deviation within the tolerance of TI % ```,,,-`-`,,`,,`,`,,` - O BSI 06-2000 Copyright European Committee for Standardization Provided by IHS under license with CEN No reproduction or networking permitted without license from IHS Not for Resale ~~ S T D - B S I BS EN 12594-2-ENGL 0 Il b b b 0854977 b I BS EN 12544-2:2000 BSI - British Standards Institution BSI is the independent national body responsible for preparing British Standards It presents the UK view on standards in Europe and at the international level It is incorporated by Royal Charter Revisions British Standards are updated by amendment or revision Users of British Standards should make sure that they possess the latest amendments or editions It is the constant aim of BSI to improve the quality of our products and services We would be grateful if anyone finding an inaccuracy or ambiguity while using this British Standard would inform the Secretary of the technical committee responsible, the identity of which can be found on the inside front cover Tel 020 8996 9OOO Fax: 020 8996 7400 BSI offers members an individual updating service called PLUS which ensures that subscribers automaticallyreceive the latest editions of sỵandasds Buying standards Orders for all BSI, international and foreign standards publications should be addressed to Customer Services Tel 020 8996 9001 Fax: 020 8996 7001 in response to orders for international standards, it is BSI policy to supply the BSI implementation of those that have been published as British Standads, unless otherwise requested information on standards BSI provides a wide range of infonnation on national, European and international standards through its Library and its Technical Help to Exporters Service Various BSI eledronic infonnation services are also available which give details on all its products and services Contact the Information Centre Tel 020 8996 7111 Fax: 020 8996 7048 Subscribing members of BSI are kept up to date with standards developments and receive substantial discounts on the purchase price of stan&ds For details of these and other benefits contact Membership Administration Tel 020 8996 7002 Fax 020 8996 7001 Copyright Copyright subsists in all BSI publications BSI also holds the copyright, in the UK, of the publications of the international standardization bodies Except as permitted under the Copyright, Designs and Patents Act 1988no extract may be reproduced, stored in a retrieval system or transmitted in any form or by any means - 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