IEC TR 62396-8:2020

Process management for avionics - Atmospheric radiation effects - Part 8: Proton, electron, pion, muon, alpha-ray fluxes and single event effects in avionics electronic equipment - Awareness guidelines

IEC 62396-8:2020 is intended to provide awareness and guidance with regard to the effects of small particles (that is, protons, electrons, pions and muon fluxes) and single event effects on avionics electronics used in aircraft operating at altitudes up to 60 000 feet (18 300 m). This is an emerging topic and lacks substantive supporting data. This document is intended to help aerospace or ground level electronic equipment manufacturers and designers by providing awareness guidance for this new emerging topic.
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.

General Information

• Status: Published
• Publication Date: 27-Apr-2020
• ICS: 03.100.50 - Production. Production management
• ICS: 31.020 - Electronic components in general
• ICS: 49.060 - Aerospace electric equipment and systems
• Technical Committee: TC 107 - Process management for avionics
• Current Stage: PPUB - Publication issued
• Completion Date: 28-Apr-2020

Standards Content (Sample)

IEC TR 62396-8
Edition 1.0 2020-04
TECHNICAL
REPORT
colourcolour
insinsiidede
Process management for avionics – Atmospheric radiation effects –
Part 8: Proton, electron, pion, muon, alpha-ray fluxes and single event effects
in avionics electronic equipment – Awareness guidelines
IEC TR 62396-8:2020-04 (en)
---------------------- Page: 1 ----------------------
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IEC TR 62396-8
Edition 1.0 2020-04
TECHNICAL
REPORT
colourcolour
insinsiidede
Process management for avionics – Atmospheric radiation effects –
Part 8: Proton, electron, pion, muon, alpha-ray fluxes and single event effects
in avionics electronic equipment – Awareness guidelines
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 03.100.50; 31.020; 49.060 ISBN 978-2-8322-8010-2

Warning! Make sure that you obtained this publication from an authorized distributor.

® Registered trademark of the International Electrotechnical Commission
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– 2 – IEC TR 62396-8:2020 © IEC 2020
CONTENTS

FOREWORD ........................................................................................................................... 5

INTRODUCTION ..................................................................................................................... 7

1 Scope .............................................................................................................................. 8

2 Normative references ...................................................................................................... 8

3 Terms, definitions, abbreviated terms and acronyms ....................................................... 8

3.1 Terms and definitions .............................................................................................. 9

3.2 Abbreviated terms and acronyms .......................................................................... 10

4 Technical awareness ..................................................................................................... 12

4.1 Basic knowledge of atmospheric secondary particles ............................................ 12

4.2 Four typical hierarchies of faulty conditions in electronic equipment: Fault –

error – hazard – failure ......................................................................................... 15

4.3 General sources of radiation ................................................................................. 18

4.3.1 General sources of terrestrial radiation .......................................................... 18

4.3.2 Atmospheric radiation particles ...................................................................... 19

4.3.3 Spectra at the avionics altitude ...................................................................... 22

4.4 Particle considerations .......................................................................................... 25

4.4.1 General ......................................................................................................... 25

4.4.2 Alpha particles ............................................................................................... 25

4.4.3 Protons .......................................................................................................... 26

4.4.4 Muons and pions ........................................................................................... 30

4.4.5 Low-energy neutrons ..................................................................................... 32

4.4.6 High-energy neutrons .................................................................................... 33

4.5 Conclusion and guidelines .................................................................................... 43

Annex A (informative) CMOS semiconductor devices ......................................................... 45

Annex B (informative) General description of radiation effects ............................................ 48

B.1 Radiation effects in semiconductor materials by a charged particle – Charge

collection and bipolar action .................................................................................. 48

B.2 Radiation effects by protons .................................................................................. 49

B.3 Radiation effects by low-energy neutrons .............................................................. 51

B.4 Radiation effects by high-energy neutrons ............................................................ 52

B.5 Radiation effects by heavy ions ............................................................................. 53

Bibliography .......................................................................................................................... 54

Figure 1 – Cosmic rays as origin of single event effects ........................................................ 13

Figure 2 – Initial stage of secondary particle production ........................................................ 14

Figure 3 – Differential high-energy neutron spectrum at sea level in NYC ............................. 14

Figure 4 – Long-term cyclic variation in neutron flux measured at Moscow Neutron

Monitor Center ...................................................................................................................... 15

Figure 5 – Differential proton spectra originating from solar-minimum sun, from big

flares on the sun, and from the galactic core ......................................................................... 15

Figure 6 – Typical hierarchy of fault conditions: Fault-error-failure ........................................ 18

Figure 7 – Sources of atmospheric ionizing radiation: Nuclear reactions and radioactive

decay .................................................................................................................................... 19

Figure 8 – Differential flux of secondary cosmic rays at avionics altitude (10 000 m)

above NYC sea level ............................................................................................................ 22

Figure 9 – Differential flux of terrestrial radiation at NYC sea level ........................................ 23

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IEC TR 62396-8:2020 © IEC 2020 – 3 –

Figure 10 – Measured differential flux of high-energy neutrons at NYC sea level and at

avionics altitudes (5 000 m, 11 000 m and 20 000 m) ............................................................ 24

Figure 11 – Cumulative flux of terrestrial radiation at avionics altitude above NYC sea

level 25
Figure 12 – Comparison of measured cross section of memory devices irradiated by

high-energy protons and neutrons ......................................................................................... 27

Figure 13 – Simplified scheme of muon/pion irradiation system ............................................ 30

Figure 14 – Nuclear capture of cross section of cadmium isotopes ....................................... 32

Figure 15 – Neutron energy spectra of monoenergetic neutron beam facilities ...................... 35

Figure 16 – Neutron energy spectra from radioisotope neutron sources ................................ 35

Figure 17 – Simplified high-energy neutron beam source in a quasi-monoenergetic

neutron source ...................................................................................................................... 37

Figure 18 – Neutron energy spectra of quasi-monoenergetic neutron beam facilities ............ 38

Figure 19 – Conceptual illustration of cross section data obtained by (quasi-)

monoenergetic neutron sources and fitting curve by Weibull fit ............................................. 39

Figure 20 – Simplified high-energy neutron beam source in a spallation neutron source ....... 41

Figure 21 – Neutron energy spectra of spallation neutron sources and terrestrial field .......... 42

Figure A.1 – Basic substrate structure used for CMOSFET devices on the stripe

structure of p- and n-wells and cross sections of triple and dual wells ................................... 45

Figure A.2 – SRAM function and layout ................................................................................. 46

Figure A.3 – Example of logic circuit ..................................................................................... 46

Figure A.4 – Example of electronic system implementation ................................................... 47

Figure A.5 – Example of stack layers in an electronic system ............................................... 47

Figure B.1 – Charge collection in a semiconductor structure by funnelling ............................ 48

Figure B.2 – Bipolar action model in a triple well n-MOSFET structure .................................. 49

Figure B.3 – Charge deposition density of various particles in silicon as a function of

particle energy ...................................................................................................................... 50

Figure B.4 – Total nuclear reaction cross section of high-energy proton and neutron in

silicon ................................................................................................................................... 50

Figure B.5 – Microscopic fault mechanism due to spallation reaction of high-energy

neutron and proton in a SRAM cell ........................................................................................ 51

Figure B.6 – (n,α) reaction cross section of low-energy neutrons with B ............................ 52

Figure B.7 – Calculated energy spectra of Li and He produced by neutron capture
10 7

reaction with B(n,α) Li reaction ........................................................................................ 52

Figure B.8 – Ranges of typical isotopes produced by nuclear spallation reaction of

high-energy neutron in silicon ............................................................................................... 53

Figure B.9 – Calculated energy spectra of elements produced by nuclear spallation

reaction of high-energy neutrons in silicon at Tokyo sea level ............................................... 53

Table 1 – General modes of faults ........................................................................................ 17

Table 2 – Properties of atmospheric radiation particles ......................................................... 19

Table 3 – Selected data sources for spectra of atmospheric radiation particles ..................... 22

Table 4 – Non-exhaustive list of methods for alpha-particle SEE measurements ................... 26

Table 5 – Non-exhaustive list of facilities for proton irradiation .............................................. 27

Table 6 – Non-exhaustive list of facilities for muon irradiation ............................................... 31

Table 7 – Non-exhaustive list of facilities for thermal/epi-thermal neutron irradiation ............. 33

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– 4 – IEC TR 62396-8:2020 © IEC 2020

Table 8 – Non-exhaustive list of facilities for low-energy neutron irradiation .......................... 36

Table 9 – Non-exhaustive list of facilities for quasi-monoenergetic neutron irradiation .......... 40

Table 10 – Non-exhaustive list of facilities for nuclear spallation neutron irradiation ............. 42

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IEC TR 62396-8:2020 © IEC 2020 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
PROCESS MANAGEMENT FOR AVIONICS –
ATMOSPHERIC RADIATION EFFECTS –
Part 8: Proton, electron, pion, muon, alpha-ray fluxes and single event
effects in avionics electronic equipment – Awareness guidelines
FOREWORD

1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising

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9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent

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The main task of IEC technical committees is to prepare International Standards. However, a

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data of a different kind from that which is normally published as an International Standard, for

example "state of the art".

IEC TR 62396-8, which is a Technical Report, has been prepared by IEC technical committee

107: Process management for avionics.
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– 6 – IEC TR 62396-8:2020 © IEC 2020
The text of this Technical Report is based on the following documents:
Draft TR Report on voting
107/355/DTR 107/365/RVDTR

Full information on the voting for the approval of this Technical Report can be found in the

report on voting indicated in the above table.

This document has been drafted in accordance with the ISO/IEC Directives, Part 2.

A list of all the parts in the IEC 62396 series, published under the general title Process

management for avionics – Atmospheric radiation effects, can be found on the IEC website.

The committee has decided that the contents of this document will remain unchanged until the

stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to

the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.

IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates

that it contains colours which are considered to be useful for the correct understanding

of its contents. Users should therefore print this document using a colour printer.

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IEC TR 62396-8:2020 © IEC 2020 – 7 –
INTRODUCTION

Atmospheric radiation can be responsible for causing single event effects (SEEs) in electronic

equipment. Beside neutrons and protons, there are other atmospheric radiation sources (for

example electrons, pions and muons), which are currently regarded as minor sources, which

can also affect electronics in avionics and terrestrial applications. This is currently a new

emerging topic with a limited amount of test data and supporting information.

This document, as part of the IEC 62396 series, provides awareness on this new emerging topic

in order to inform avionics systems designers, electronic equipment manufacturers and

component manufacturers and their customers of the kind of ionising radiation environment that

their electronic devices can be subjected to in aircraft and the potential effects this radiation

environment can have on those electronic devices.

This awareness is unavoidable due to the aggressive scaling of electronic semiconductor

devices to smaller and smaller transistor feature sizes where the impact of these radiation

sources can become visible or even significant in the future. For example, some evidence of

muon effects has appeared in the literature, in which the impact of muons seems to be negligible

at present. This document gives a comprehensive survey on the nature of these particles,

atmospheric spectra, induced phenomena and possible testing facilities with their radiation

sources; it also provides orientation in order to prepare avionics in the future.

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– 8 – IEC TR 62396-8:2020 © IEC 2020
PROCESS MANAGEMENT FOR AVIONICS –
ATMOSPHERIC RADIATION EFFECTS –
Part 8: Proton, electron, pion, muon, alpha-ray fluxes and single event
effects in avionics electronic equipment – Awareness guidelines
1 Scope

This part of IEC 62396 is intended to provide awareness and guidance with regard to the effects

of small particles (that is, protons, electrons, pions and muon fluxes) and single event effects

on avionics electronics used in aircraft operating at altitudes up to 60 000 feet (18 300 m). This

is an emerging topic and lacks substantive supporting data. This document is intended to help

aerospace or ground level electronic equipment manufacturers and designers by providing

awareness guidance for this new emerging topic.

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.

NOTE 1 The overall system safety methodology is usually expanded to accommodate the single event effects rates

and to demonstrate the suitability of the electronics for application at the electronic component, electronic equipment

and system level.

NOTE 2 For the purposes of this document the terms "electronic device" and "electronic component" are used

interchangeably.

Although developed for the avionics industry, this document can be used by other industrial

sectors at their discretion.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements 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.

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
3 Terms, definitions, abbreviated terms and acronyms

For the purposes of this document, the terms, definitions, abbreviated terms and acronyms

given in IEC 62396-1 and the following apply.

ISO and IEC maintain terminological databases for use in standardization at the following

addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
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IEC TR 62396-8:2020 © IEC 2020 – 9 –
3.1 Terms and definitions
3.1.1
AND

logic gate which produces, in digital electronics, an output that is true (1) if both inputs are true

(1) and an output false (0) if neither or only one input is true (1)
3.1.2
bipolar action

phenomenon whereby some electrons or holes stay in the bulk of the semiconductor and switch

on the parasitic transistor to change the data states in memory elements
3.1.3
charge collection
part of electrons or holes pairs collected into storage nodes

Note 1 to entry: Electrons or holes are generated along with the trajectory of high-energy charged particles. This

phenomenon is called charge deposition.
3.1.4
linear energy transfer
LET

rate of decrease with distance of the kinetic energy of an ionizing particle, due to the ionization

caused by that particle

Note 1 to entry: LET describes the action of radiation into matter. It is related to stopping power which in nuclear

physics is defined as the retarding force acting on charged particles, typically alpha and beta particles, due to

interaction with matter, resulting in loss of particle energy.
2 −1

Note 2 to entry: LET is typically quantified in units of MeV·cm ·mg , to account for the density of the material

through which the particle travels.
3.1.5
multi-node transient
MNT

multiple transients (SETs) produced along with a high-energy charged particle or in an area

affected by bipolar action
3.1.6
negative-AND
NAND

logic gate which produces, in digital electronics, an output that is false (0) only if all its inputs

are true (1) and an output true (1) if one or both inputs are false (0)
[SOURCE: IEC 62239-1:2018, 3.1.22]
3.1.7
negative-OR
NOR

logic gate which produces, in digital electronics, an output that is true (1) if both the inputs are

false (0) and an output false (0) if one or both inputs are true (1)
[SOURCE: IEC 62239-1:2018, 3.1.23]
3.1.8

logic gate which produces, in digital electronics, an output that is true (1) if one of both inputs

is true (1) and an output false (0) if neither input is true (1)
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3.1.9
soft error rate
SER

rate at which a device or system encounters or is predicted to encounter soft errors

Note 1 to entry: Usually, this is expressed as either the number of failures-in-time (FIT) or mean time between

failures (MTBF). The unit adopted for quantifying failures in time is called FIT, which is equivalent to one error per

billion hours of device operation. MTBF is usually given in years of device operation; to put it into perspective, one

FIT equals approximately 1 000 000 000 / (24 × 365,25) = 114 077 times more than one-year MTBF.

3.1.10
radiation induced leakage current
RILC
cumulative effect of ion-induced defects in capacitors with ultra-thin oxides

Note 1 to entry: This phenomenon can be noted in floating gate memory with thin oxide layers; data is stored

depending on the number of electrons in the floating gate. When a high-energy charged particle passes through the

tunnel oxide between the floating gate and source-drain channel underneath, a conduction path is created along the

path and stored electrons flow away, resulting in V shift or SEU.
3.1.11
(quasi-) monoenergetic neutron

neutron from a well-defined distribution of energies obtained by bombarding high-energy

charged particles at a thin metallic target

Note 1 to entry: Monoenergetic neutron beams have a single narrow flux peak at a particular neutron energy. All

the neutrons in the beam have energies at or close to the nominal energy.

Note 2 to entry: Quasi-monoenergetic neutron beams have a narrow flux peak at a nominal neutron energy and a

tail covering a broad range of energies below the nominal energy. Typically, about half the neutrons have energy

close to the nominal energy and about half are in the low-energy tail.
3.2 Abbreviated terms and acronyms
ANITA Atmospheric-like Neutrons from thick Target
BNCT boron neutron capture therapy
BNL Brookhaven National Laboratory (USA)
BOX buried oxide
BPSG boron phosphorus silicate glass (also named borophosphosilicate glass)
CAM content addressable memory
CEA / CVA Atomic Energy Commission / Centre of Valduc (France)

CEA / DIF Atomic Energy Commission / “Direction” of military applications Ile de France

(France)
CMOS complementary metal oxide semiconductor
CMOSFET complementary metal oxide semiconductor field effect transistor
CMP chemical mechanical polishing
CNL Crocker Nuclear Laboratory (USA)
CNRF Cold Neutron Research Facility
CPU central processing unit
CYRIC CYclotron and RadioIsotope Center (Tohoku University, Japan)
DD displacement damage
DICE dual interlocked storage cell
DMR double modular redundancy
DRAM dynamic random access memory
DUT device under test
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IEC TR 62396-8:2020 © IEC 2020 – 11 –
ECC error correction code / error checking and correction
ECU electronic control unit
EEPROM electrically erasable programmable read-only memory
EMI electro-magnetic interference
FD fully depleted
FET field effect transistor
FF flip-flop
FIT failure in time
FNL Fast Neutron Laboratory (Tohoku University, Japan)
FPGA field-programmable gate array
GPU graphic processing unit
HKMG high-k metal gate
HLA hyper low alpha
IGBT insulated gate bipolar transistor
INC intra nuclear cascade
IUCF Indiana University Cyclotron Facility (USA)
J-PARC Japan Proton Accelerator Research Complex (Japan)

L1 / L2 level 1 / level 2 (related to microprocessor cache memories, "level 1" cache

memory being usually built onto the microprocessor device itself, “level 2” cache

memory being usually on a separate device or expansion card) [SOURCE:
IEC TR 62396-7:2017, 3.2]
L3 level 3 (related to, “level 3” cache memory being usually built onto the CPU
module or motherboard and working together with L1 and L2 cache memories
for improving processing performance
LANSCE Los Alamos National Science Center (USA)
LAMPF Los Alamos Meson Physics Facility (USA)
LBNL Lawrence Berkeley National Laboratory (USA)
LENS low-energy neutron source (university-based pulsed neutron source at IUCF)
LET linear energy transfer
MBU multipl
...