IEC_TS_62396-5-2008.pdf

IEC/TS 62396-5Edition 1.0 2008-08TECHNICAL SPECIFICATION Process management for avionics Atmospheric radiation effects Part 5:Guidelines for assessing thermal neutron fluxes and effects in avionics systems IEC/TS 62396-5:2008(E)LICENSED TO MECON Limited.-RANCHI/BANGALOREFOR INTERNAL USE AT THIS LOCATION ONLY,SUPPLIED BY BOOK SUPPLY BUREAU.THIS PUBLICATION IS COPYRIGHT PROTECTED Copyright 2008 IEC,Geneva,Switzerland All rights reserved.Unless otherwise specified,no part of this publication may be reproduced or utilized in any form or by any means,electronic or mechanical,including photocopying and microfilm,without permission in writing from either IEC or IECs member National Committee in the country of the requester.If you have any questions about IEC copyright or have an enquiry about obtaining additional rights to this publication,please contact the address below or your local IEC member National Committee for further information.Droits de reproduction rservs.Sauf indication contraire,aucune partie de cette publication ne peut tre reproduite ni utilise sous quelque forme que ce soit et par aucun procd,lectronique ou mcanique,y compris la photocopie et les microfilms,sans laccord crit de la CEI ou du Comit national de la CEI du pays du demandeur.Si vous avez des questions sur le copyright de la CEI ou si vous dsirez obtenir des droits supplmentaires sur cette publication,utilisez les coordonnes ci-aprs ou contactez le Comit national de la CEI de votre pays de rsidence.IEC Central Office 3,rue de Varemb CH-1211 Geneva 20 Switzerland Email:inmailiec.ch Web:www.iec.ch About IEC publications The technical content of IEC publications is kept under constant review by the IEC.Please make sure that you have the latest edition,a corrigenda or an amendment might have been published.?Catalogue of IEC publications:www.iec.ch/searchpub The IEC on-line Catalogue enables you to search by a variety of criteria(reference number,text,technical committee,).It also gives information on projects,withdrawn and replaced publications.?IEC Just Published:www.iec.ch/online_news/justpub Stay up to date on all new IEC publications.Just Published details twice a month all new publications released.Available on-line and also by email.?Electropedia:www.electropedia.org The worlds leading online dictionary of electronic and electrical terms containing more than 20 000 terms and definitions in English and French,with equivalent terms in additional languages.Also known as the International Electrotechnical Vocabulary online.?Customer Service Centre:www.iec.ch/webstore/custserv If you wish to give us your feedback on this publication or need further assistance,please visit the Customer Service Centre FAQ or contact us:Email:csciec.ch Tel.:+41 22 919 02 11 Fax:+41 22 919 03 00 LICENSED TO MECON Limited.-RANCHI/BANGALOREFOR INTERNAL USE AT THIS LOCATION ONLY,SUPPLIED BY BOOK SUPPLY BUREAU.IEC/TS 62396-5Edition 1.0 2008-08TECHNICAL SPECIFICATION Process management for avionics Atmospheric radiation effects Part 5:Guidelines for assessing thermal neutron fluxes and effects in avionics systems INTERNATIONAL ELECTROTECHNICAL COMMISSION RICS 03.100.50;31.020;49.060 PRICE CODEISBN 2-8318-9959-1 Registered trademark of the International Electrotechnical Commission LICENSED TO MECON Limited.-RANCHI/BANGALOREFOR INTERNAL USE AT THIS LOCATION ONLY,SUPPLIED BY BOOK SUPPLY BUREAU.2 TS 62396-5 IEC:2008(E)CONTENTS FOREWORD.3 1 Scope.5 2 Normative references.5 3 Terms and definitions.5 4 Overview of thermal neutron single event rate calculation.5 5 Thermal neutron flux inside an airliner.6 5.1 Definition of thermal neutron.6 5.2 Overview.7 5.3 Background on aircraft measurements.7 5.4 Calculational approach.8 5.5 Processing of in-flight neutron flux data.9 6 Thermal neutron SEU cross sections.12 6.1 Overview of the issue.12 6.2 Mechanism involved.13 6.3 Thermal neutron SEU cross sections and Ratio-2.14 7 Recommendation for devices in avionics at present time.16 Bibliography.17 Figure 1 Atmospheric neutron spectra measured in four aircraft.9 Table 1 Tabulation of the various atmospheric neutron measurements used.9 Table 2 Comparison of thermal and high energy neutron fluxes and their ratios.11 Table 3 Calculated neutron fluxes in the Boeing 747 structure.12 Table 4 SRAM SEU cross sections induced by thermal and high energy neutrons.15 LICENSED TO MECON Limited.-RANCHI/BANGALOREFOR INTERNAL USE AT THIS LOCATION ONLY,SUPPLIED BY BOOK SUPPLY BUREAU.TS 62396-5 IEC:2008(E)3 INTERNATIONAL ELECTROTECHNICAL COMMISSION _ PROCESS MANAGEMENT FOR AVIONICS ATMOSPHERIC RADIATION EFFECTS Part 5:Guidelines for assessing thermal neutron fluxes and effects in avionics systems FOREWORD 1)The International Electrotechnical Commission(IEC)is a worldwide organization for standardization comprising all national electrotechnical committees(IEC National Committees).The object of IEC is to promote international co-operation on all questions concerning standardization in the electric