The X-ray yields of stopping protons in an iron-nickel-cobalt alloy are calculated for use in predicting radiation damage in encased electronic devices

Fogarty, N. T.

Khandelwal, G. S.

Wilson, J. W.

English

NASA Technical Reports Server

NASA Technical Memorandum 100619 
* 
X-Ray Production in Low Energy Proton Stopping 
Jm W. Wilson 
G. S. Khandelwd 
Nm T. Fogarty 
N 88- 2 35 82 
April 1988 
National Aeronautics and 
Space Administration 
Langley Research Center 
Hampton, Virginia 23665-5225 
https://ntrs.nasa.gov/search.jsp?R=19880014198 2020-03-20T06:18:02+00:00Z
X-RAY PRODUCTION I N  LOW ENERGY PROTON STOPPING 
J. W. Wilson, G. S .  Khandelwal and T. N. F o g a r t y  
A b s t r a c t  
The X-ray y i e l d s  o f  s t o p p i n g  p ro tons  i n  an i r o n - n i c k e l - c o b a l t  a l l o y  a r e  
c a l c u l a t e d  f o r  use i n  p r e d i c t i n g  r a d i a t i o n  damage i n  encased e l e c t r o n i c  
dev ices.  
2 
INTRODUCTION 
It i s  observed i n  some e l e c t r o n i c  dev i ces  t h a t  r a d i a t i o n  e f f e c t s  r e s u l t  
f rom low energy p r o t o n s  s t o p p i n g  i n  t h e  e x t e r n a l  c a s i n g  m a t e r i a l s  w i t h o u t  
c r o s s i n g  t h e  d e v i c e  s e n s i t i v e  r e g i o n  ( r e f s .  1 and 2). I n  o r d e r  t o  e x p l a i n  
t h i s  phenomenon, secondary r a d i a t i o n s  produced i n  t h e  c a s i n g  m a t e r i a l  a r e  
suspect. The most l i k e l y  r a d i a t i o n s  t o  p e n e t r a t e  t h e  c a s i n g  m a t e r i a l  a r e  t h e  
X-rays produced by p r o t o n  impact. I n  t h e  p resen t  no te ,  t h e  X-ray y i e l d s  from 
s t o p p i n g  p r o t o n s  i n  an i r o n - n i c k e l  -cobal  t a1 1 oy a r e  c a l  c u l  ated. 
a r e  e a s i l y  extended t o  o t h e r  m a t e r i a l s .  
The methods 
3 
X-RAY PRODUCTION CROSS SECTIONS 
h 
The K-she l l  and L - s h e l l  i o n i z a t i o n  c ross  s e c t i o n s  f o r  i r o n ,  c o b a l t ,  and 
n i c k e l  have been eva lua ted  w i t h  t h e  r e s u l t s  g i ven  i n  Tables 1 and 2, u s i n g  t h e  
work of Khandelwal , Choi , and Merzbacher ( re f .  3). The X-ray f luorescence 
y i e l d  i s  i n  c o m p e t i t i o n  w i t h  Auger and Coster -Kron ig  t r a n s i t i o n s ,  and t h e  
f r a c t i o n a l  f l uo rescence  y i e l d  i s  g i ven  i n  r e f s .  4, 5, and 6. The K-she l l  and 
L - s h e l l  f r a c t i o n a l  y i e l d s  a re  shown i n  Table 3. 
LOW ENERGY PROTON TRANSPORT 
I f  n u c l e a r  processes and s t r a g g l i n g  a r e  neg lec ted ,  t h e  p r o t o n  t r a n s p o r t  
e q u a t i o n  i s  g i v e n  as 
where $(x,E) i s  p r o t o n  f l u x  a t  x of energy E. The s o l u t i o n  i s  g i ven  as 
E where r ( E )  = l o  d E ' / S ( E ' )  and E ( X )  i s  i n v e r s e  of R(E). The r e s u l t  
( e q u a t i o n  2) can now be use'd t o  c a l c u l a t e  t h e  X-ray y i e l d s  YX(x)as 
( 3 )  
where a X ( E )  i s  t h e  macroscopic  i o n i z a t i o n  c ross  s e c t i o n  and wx i s  t h e  s h i e l d ' s  
4 
f r a c t i o n a l  f l uo rescence  y i e l d .  
i s  
The y i e l d  f o r  a monoenergetic beam o f  p ro tons  
where ro = R(EO) and r = R(E). The r e s u l t  i s  
- 
a s  one would presume. The t o t a l  y i e l d  Yx i n  s t o p p i n g  i s  t hen  
The r e q u i r e d  f u n c t i o n s  w i l l  now be approx imated t o  e v a l u a t e  t h e  i n t e g r a l  
( e q u a t i o n  6). 
STOPPING POWER AND CROSS SECTION PARAMETERS 
The low energy p o r t i o n  o f  t h e  s topp ing  power cu rve  was shown by Fermi t o  
be 
S ( E )  = a P'T 
The s t o p p i n g  power t o  seve ra l  MeV i s  adequate ly  approx imated by 
n 
(7) 
5 
h 
and i s  known t o  have a maximum a t  app rox ima te l y  Em a 100 keV so t h a t  
and 
a r e  s u f f i c i e n t  t o  de termine t h e  c o e f f i c i e n t s  a and b t o  f i n d  
E 
- 
S ( E )  = Z Sm /(I + 
E m  m 
The range i s  t hen  found t o  be 
E 
(1 +-) 
4- 
Em 
R ( E )  = 
m S 
Assuming t h e  d e n s i t y  t o  be 8.4 g/cm3 and t a k i n g  
i o n i z a t i o n  c ross  s e c t i o n s  can be reasonab ly  approx imated by 
Sm 246 keV/p, we f i n d  t h e  
which h o l d s  below 1 MeV. Th is  g i v e s  a t o t a l  y i e l d  o f  
6 
We have taken t h e  compos i t i on  of t h e  a l l o y  t o  be 54 percent  Fey 29 pe rcen t  N i ,  
and 17 pe rcen t  Co t o  f i n d  t h e  K s h e l l  f l uo rescence  y i e l d  f o r  1 MeV p ro tons  t o  
be 
- 
y K  = 9 x X-rays /pro ton  
To assess t h e  e f f e c t s  o f  t hese  X-rays on d e v i c e  performance r e q u i r e s  
a d d i t i o n a l  t r a n s p o r t  c a l c u l a t i o n s  of t h e  X-rays th rough  t h e  d e v i c e  i t s e l f .  
CONCLUDING REMARKS 
The p resen t  fo rma l i sm p rov ides  a means o f  e s t i m a t i n g  t h e  X-ray p r o d u c t i o n  
i n  p r o t o n  exposures. The f l uo rescence  y i e l d  may be used as source terms i n  a 
p h o t o n / e l e c t r o n  t r a n s p o r t  code t o  f u r t h e r  eva lua te  t h e i r  e f f e c t s  on dev i ce  
performance. 
7 
REFERENCES 
1. K. K. Diogu, T. N. Fogar ty ,  A. Kumar, F. C. Wang, and C. F. Herman; 
Charge An omaly a t  MOS I n t e r f a c e s  Submit ted t o  One MeV Pro ton  
Rad ia t i on .  
N a t u r a l  Space R a d i a t i o n  and VLSI Technology, t o  be pub l ished.  
Proceedings o f  NASA/Pra i r ie  View A & M Conference on 
2. T. N. Fogar ty ,  C. Herman, K. Diogu, and F. Wang; S i m u l a t i o n  o f  Na tu ra l  
Space Radi a t  i on E f f e c t s  on VLSI Techno1 ogy ; E l  e c t  rochemi c a l  Soc ie ty  , 
vo l .  87, no. 2, pp. 880-1, 1987. 
3. G. S. Khandelwal , B. H. Choi , and E. Merzbacher, Atomic Data and Nuclear  
Data, Tables 1, 103 (1969). 
4. W. Bambynek e t  a1 . , X-Ray F1 uorescence Y ie lds  , Auger, and Coster -Kron i  g 
T r a n s i t i o n  P r o b a b i l i t i e s .  Rev. Mod. Phys. - 44, p. 716, 1972. 
5. M. 0. Krause, Atomic R a d i a t i v e  and R a d i a t i o n l e s s  Y i e l d s  o f  K-  and L- 
S h e l l s ,  J. Phys. Chem. Ref. Data, vo l .  8, no. 2, p. 307, 1979. 
6. E. J. McGuire, Atomic L -She l l  Coster-Kronig,  Auger, and R a d i a t i v e  Rates 
and F luorescence Y i e l d s  f o r  Na - Tl . ,  Phys. Rev. vo l .  A3, no. 2, 
p .  587, 1971. 
Table 1 - K-shell I o n i z a t i o n  Cross Sect ions  ( b )  as a Func t ion  
o f  Pro ton  Energy (MeV) 
E Fe co N i  
0.1 0.054 .035 .021 
0.5 11.0 8.49 5.86 
1.0 70.8 50.3 35.5 
c 
9 
Table 2 - L - s h e l l  I o n i z a t i o n  Cross Sec t ions  ( b )  
as  a F u n c t i o n  o f  Proton Energy (MeV) 
E Fe co N i  
0.1 4.27E4 2.71E4 1.62E4 
0.5 3.68E5 2.80E5 2,0665 
1.0 5.28E5 4.14E5 3.25E5 
10 
Tab le  3 - F r a c t i o n a l  F luorescence Y i e l d  
Element 
- 
K w 
c 
Fe 
co 
N i  
0.34 
-0.37 
0.41 
6.4E - 3 
7.7E - 3 
9.1E - 3 
Report Documentation Page 
1. Report No. 
NASA TM-100619 
2. Government Accession No. 
7. Authorls) 
17. Key Words (Suggested by Author(s)l 
X-ray production 
Protons 
radiation damage 
J. W. Wilson 
G. S. Khandelwal 
N. T. Fogarty 
NASA Langley Research Center 
Hampton, VA 23665-5225 
9. Performing Organization Name and Address 
18. Distribution Statement 
Unclassified - Unlimited 
Subject Category 54 
12. Sponsoring Agency Name and Address 
National Aeronautics and Space Administration 
Washington, DC 20546-0001 
19. Security Classif. (of this report) 20. Security Classif. (of this page) 21. No. of pages 
Unclassified Unclassified 11 
15. Supplementary Notes 
J. W. Wilson, Langley Research Center, Hampton, VA 
G. S. Khandelwal , Old Dominion University, Norfolk, VA 
N. T. Fogarty, Hampton University, Hampton, VA 
22. Price 
A0 2 
3. Recipient's Catalog No. 
5. Report Date 
April 1988 
6. Performing Organization Code 
8. Performing Organization Report No. 
10. Work Unit No. 
199-22-76-01 
~ 
11. Contract or Grant No. 
13. Type of Report and Period Covered 
Technical Memorandum 
14. Sponsoring bgency Code 
16. Abstract 
The X-ray yields of stopping protons in an iron-nickel-cobalt alloy are 
calculated for use in predicting radiation damage in encased electronic 
devices . 


X-ray production in low energy proton stopping

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server