Standard No.:	GB/T 34956-2017
English Name:	Atmospheric radiation effects―Accommodation of atmospheric radiation effects via single event effects within avionics electronic equipment
Chinese Name:	大气辐射影响 航空电子设备单粒子效应防护设计指南
Chinese Classification:	V04    Basic standards and general methods
Professional Classification:	GB    National Standard
Source Content Issued by:	AQSIQ; SAC
Issued on:	2017-11-01
Implemented on:	2018-5-1
Status:	valid
Target Language:	English
File Format:	PDF
Word Count:	37000 words
Translation Price(USD):	1110.0
Delivery:	via email in 1 business day

This part is drafted in accordance with the rules given in the GB/T 1.1-2009. This standard is identical with International Standard IEC 62396-1:2016 Process Management for Avionics — Atmospheric Radiation Effects — Part 1: Accommodation of Atmospheric Radiation Effects Via Single Event Effects within Avionics Electronic Equipment. For the purposes of this standard, the following editorial changes have also been made with respect to the IEC 62396-1:2016: — the name of this standard is changed to Atmospheric Radiation Effects — Accommodation of Atmospheric Radiation Effects Via Single Event Effects within Avionics Electronic Equipment. — addition of Annex NA (informative) and Annex NB (informative); This standard was proposed by Aviation Industry Corporation of China, Ltd. This standard is under the jurisdiction of SAC/TC 427 (National Technical Committee 427 on Process Management for Avionics of Standardization Administration of China).   Introduction The same atmospheric radiation (neutrons and protons) that is responsible for the radiation exposure that crew and passengers acquire while flying is also responsible for causing the single event effects (SEE) in the avionics electronic equipment. There has been much work carried out over the last few years related to the radiation exposure of aircraft passengers and crew. A standardised industry approach on the effect of the atmospheric neutrons on electronics should be viewed as consistent with, and an extension of, the on-going activities related to the radiation exposure of aircraft passengers and crew. Atmospheric radiation effects are one factor that could contribute to equipment hard and soft fault rates. From a system safety perspective, using derived fault rate values, the existing methodology described in ARP4754A (accommodation of hard and soft fault rates in general) will also accommodate atmospheric radiation effect rates. In addition, this standard refers to the JEDEC Standard JESD 89A, which relates to soft errors in electronics by atmospheric radiation at ground level (at altitudes less than 3 040 m). This standard informs avionics systems designers, electronic equipment manufacturers, component manufacturers and their customers of the kind of ionising radiation environment that their devices will be subjected to in aircraft, the potential effects this radiation environment can have on those devices, and some general approaches for dealing with these effects. Atmospheric Radiation Effects — Accommodation of Atmospheric Radiation Effects Via Single Event Effects within Avionics Electronic Equipment 1 Scope This standard is intended to provide guidance on atmospheric radiation effects on avionics electronics used in aircraft operating at altitudes up to 18.3 km. It defines the radiation environment, the effects of that environment on electronics and provides design considerations for the accommodation of those effects within avionics systems. This standard defines the radiation environment and its radiation environmental effects in avionics, and proposes the design requirements for the prevention and control of these effects in avionics systems. This standard is intended to help avionics equipment manufacturers and designers to standardise their approach to single event effects in avionics by providing guidance, leading to a standard methodology. Details of the radiation environment are provided together with identification of potential problems caused as a result of the atmospheric radiation received. Appropriate methods are given for quantifying single event effect (SEE) rates in electronic components. The overall system safety methodology should be expanded to accommodate the single event effects rates and to demonstrate the suitability of the electronics for the application at the component and system level. 2 Normative References The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. GB/T 34955-2017 Atmospheric Radiation Effects — Guidelines for Single Event Effects Testing for Avionics Systems (IEC 62396-2:2012, IDT) IEC 62239-1:2015 Process Management for Avionics — Management Plan — Part 1: Preparation and Maintenance of an Electronic Components Management Plan IEC 62396-3 Process Management for Avionics — Atmospheric Radiation Effects — Part 3: Optimising System Design to Accommodate the Single Event Effects (SEE) of Atmospheric Radiation IEC 62396-4 Process Management for Avionics — Atmospheric Radiation Effects — Part 4: Guidelines for Designing with High Voltage Aircraft Electronics and Potential Single Event Effects IEC 62396-5 Process Management for Avionics — Atmospheric Radiation Effects — Part 5: Guidelines for Assessing Tthermal Neutron Fluxes and Effects in Avionics Systems 3 Terms and Definitions For the purposes of this document, the following terms and definitions apply. Note: Users of this international standard can use alternative definitions consistent with convention within their companies. 3.1 aerospace recommended practice documents relating to avionics which are published by the Society of Automotive Engineers (SAE) 3.2 analogue single event transient ASET spurious signal or voltage produced at the output of an analogue component by the deposition of charge by a single particle 3.3 availability probability that a system is working at instant t, regardless of the number of times it may have previously failed and been repaired Note: For equipment, availability is the fraction of time the equipment is functional divided by the total time the equipment is expected to be operational, i.e. the time the equipment is functional plus any repair time. 3.4 avionics equipment environment applicable environmental conditions (as described per the equipment specification) that the equipment is able to withstand without loss or degradation in equipment performance during all of its manufacturing cycle and maintenance life Note: The length of the maintenance life is defined by the equipment manufacturer in conjunction with customers.   3.5 capable ability of a component to be used successfully in the intended application 3.6 certified assessed and compliant to an applicable standard, with maintenance of a certificate and registration 3.7 characterisation process of testing a sample of components to determine the key electrical parameter values that can be expected of all produced components of the type tested 3.8 component application process that assures that the component meets the design requirements of the equipment in which it is used 3.9 component manufacturer organisation responsible for the component specification and its production 3.10 could not duplicate (CND) reported outcome of diagnostic testing on a piece of equipment 3.11 critical charge smallest charge that will cause an SEE if injected or deposited in the sensitive volume Note: For many electronic components, the unit applied is the pico coulomb (pC); however, for small geometry components, this parameter is measured in femto coulomb (fC). 3.12 cross-section σ combination of sensitive area and probability of an interaction depositing the critical charge for a SEE Note 1: The cross-section may be calculated using the following formula: σ = number of errors/particle fluence Note 2: The units for cross-section are cm2 per electronic component or per bit (cm2/dev or cm2/bit).   3.13 double error correction triple error detection (DECTED) system or equipment methodology to test a digital word of information to determine if it has been corrupted, and if corrupted, to conditionally apply a correction Note: This methodology can correct two-bit corruptions and can detect and report three-bit corruptions. 3.14 digital single event transient (DSET) spurious digital signal or voltage, induced by the deposition of charge by a single particle that can propagate through the circuit path during one clock cycle 3.15 electron elementary particle having a mass of approximately 1/1 840 atomic mass units, and a negative charge of 1.602 × 10–19 C 3.16 electronic components management plan (ECMP) equipment manufacturer's document that defines the processes and practices for applying electronic components to an equipment or range of equipment Note: Generally, it addresses all relevant aspects of the controlling components during system design, development, production, and post-production support. 3.17 electronic component electrical or electronic device that is not subject to disassembly without destruction or impairment of design use Note: An electronic component is sometimes called electronic device, electronic part, or piece part. Example: Resistors, capacitors, diodes, integrated circuits, hybrids, application specific integrated circuits, wound components and relays.

Foreword II Introduction III 1 Scope 2 Normative References 3 Terms and Definitions 4 Abbreviations 5 Radiation Environment of the Atmosphere 6 Effects of Atmospheric Radiation on Avionics 7 Guidance for System Designs 8 Determination of Avionics Single Event Effects Rates 9 Considerations for SEE Compliance Annex A (Informative) Thermal Neutron Assessment Annex B (Informative) Methods for Calculating SEE Rates in Avionics Electronics Annex C (Informative) Review of Test Facility Available Abroad Annex D (informative) Tabular Description of Variation of Atmospheric Neutron Flux with Altitude and Latitude Annex E (Informative) Consideration of Effects at Higher Altitudes Annex F (Informative) Prediction of SEE Rates for Ions Annex G (Informative) Late News as of 2014 on SEE Cross-sections Applicable to the Atmospheric Neutron Environment Annex NA (Informative) Examples of test organization of 14 MeV neutron source in China Annex NB (Informative) Calculating SEE Rates from Non-white (Non-atmospheric Like) Neutron Cross-sections for Small Geometry Electronic Components Bibliography