Single Event Upset 4 New Space : SEU 4 NS

INTRODUCTION

On any orbit, we will get Single Event Upset (SEU) on digital parts, induced by both Galactic Cosmic Rays and/or Trapped protons. Then, at board level, it is necesssary to implement corrective action early in the design process : Hamming code, majority vote, Error Detection/correction circuitry, ... At this level, it is important to have an "Order of Magnitude"  of the SEU rate for each part, to check the compatibility with "tolerant design" implemented.

PART CHARACTERIZATION TO SEU ( N₀ elementary memory cells )

Response to Heavy Ions is modeled by a Weibull Fit:                                        |  Response High Energy Proton is modeled by a Bendel Fit:

LET_threshold in MeV.cm²/mg  |  XS_sat  (Ion saturated XS in cm².device)              |  E_thresold in MeV   |  XS_sat  (Proton Saturated XS in cm²/device )

W in MeV.cm²/mg  and  S: Shape   

SEU RATE ESTIMATION: Method # 1

(a) You need only a rough estimation, but a reliable, SEU Rate for your part.

(b) You don't know the part characterization data and you want to avoid high radiation testing cost and long delay, and radiation engineering activity

Solution : A dummy part is considered ( 72 Mbit SRAM from CYPRESS [1] ) and SEU Rates are given for any orbit, in SEU/Mbit.day

This part is highly integrated and sensitive, then you can consider this SEU Rate as a worst-case for your mission

SEU RATE ESTIMATION: Method # 2

(a) You need only a rough estimation, but a reliable, SEU Rate for your part.

(b) From existing database, you  know the part characterization data and you want to avoid radiation engineering activity over-cost

Solution : Ask for the SEU4NS code  ( SEU 4 New Space ) and run in as follow :

• INPUT     : Altitude km, Inclination in °, N₀        Heavy Ion: LET_threshold, XS, W, S           High Energy Proton : E_Threshold & XS
• OUTPUT : SEU Rate in SEU/device.day for your part

In case of High Energy Proton data are not available, PROFIT prediction is automatically taken into account

For any other case, you need to go back to "Classic Space" way to work .....

ENVIRONMENT

Trapped Protons: AP8 Solar Minimum, Galactic Cosmic Rays (GCR): GCR ISO MODEL, Atomic Number Z: [1 - 92]  / Solar Minimum

DUMMY PART CHARACTERIZATION:    72 Mbit SRAM CYC2652XV18 CYPRESS

   N₀ =72Mbit , LET_th=0.233 MeV.cm²/mg, XS_sat=  2.06 cm².device, W= 24.1 MeV.cm²/mg and S=1.38 | E_th= 10 MeV & XS=3.95 .10^-6 cm².device

 4 mm Aluminum Thickness  - LEO-MEO-GEO

4 mm Aluminum Thickness  - LEO

 7 mm Aluminum Thickness  - LEO-MEO-GEO

7 mm Aluminum Thickness  - LEO