Characterizing 

Radiation-Induced Faults 

in Microprocessors

KURT LYNN
History

Microprocessors have been affected by radiation for years. The problem is 

most research has been directed towards space, and the cosmic radiation 

bombarding satellites.

 Why haven’t we just invented a radiation-proof microchip?

 Radiation Hardened

 Is there a way to keep the microprocessors from having glitches?

 Redundant chips for backup that all vote an a result for each calculation.

2+2

=4

=4 = 2

4
What does that mean to us?

 There are three ways to limit exposure:

 Distance

 Time

 Shielding

 At what point does shielding have an effect?

 Is there a proportional effect with the amount of errors rising with exposure?

 Or is there a range of radiation where the microprocessor can still function? 

 When do the processors have such a low error percentage that they can be 

called “functional”?

0

1

2

3

4

5

0 0.25 0.5 0.75

Error Rate

Shielding

0

1

2

3

4

5

0 0.25 0.5 0.75

Error Rate

Shielding
Setting up the Experiment

 3 Flow Transmitters hooked up to a static water 

source.

 Water Max and Min flow values shouldn’t change

 Readings should remain constant without dips or 

spikes.

 The only reading changes are from the transmitters 

microprocessor itself.
Types of Failures Encountered

 Soft Shutdowns
Type 1 Failure

0

0.0005

0.001

0.0015

0.002

0.0025

0.003

0.0035

0.004

0.0045

1873 millirems 2667 millirems 3800 millirems

Avg. % of Day Failure Rate

Series 1 -2

0

2

4

6

8

10 22 Seconds

Total Failures: 50 80 81
Type 2 Failure

0.00096

0.00098

0.001

0.00102

0.00104

0.00106

0.00108

0.0011

1873 millirems 2667 millirems 3800 millirems

Avg. % of Day Failure Rate

-2

0

2

4

6

8

10 24 Seconds

Total Failures: 22 22 21
Outlier Failures

-5

0

5

10

15

20

25

30

35

40

45

-2

-1

0

1

2

3

4

5

6

09:42.009:46.009:50.009:54.009:58.010:02.010:06.010:10.010:14.010:18.010:22.010:26.010:30.010:34.010:38.010:42.010:46.0
Design of Experiment

 Equipment

 Power 

 Fluctuation

 Loss of power

 Built differently

 Able to withstand higher amounts of 

radiation

 Different margins of error with each 

transmitter

 Damage from previous experiments

 Radiation

 Types of possible exposure

 Gamma 

 Neutron

 Radiation levels

 Multiple radiation Sources

 Direction of radiation

 Fluctuation

 Direction

 Intensity
Design of Experiment

 Equipment

 Power 

 Fluctuation

 Loss of power

 Built differently

 Able to withstand higher amounts of 

radiation

 Different margins of error with each 

transmitter

 Damage from previous experiments

 Radiation

 Types of possible exposure

 Gamma 

 Neutron

 Radiation levels

 Multiple radiation Sources

 Direction of radiation

 Fluctuation

 Direction

 Intensity

.

Where to now?

 Radiation levels

 Multiple radiation Sources

 Direction of radiation

 Fluctuation

 Direction

 Intensity

2000

3000 500

1500

1000

1500
A special thanks to: 

CHRNS

NSF

Julie Borchers, 

Mike Middleton, 

Susan Deeb,

Dan Keyser,

NCNR and SURF staff.
If you try to fail and succeed, which have you done?

-George Carlin

Questions?