Table to evaluate potential radioactive nuclei production occurring in accelerator laborator

Janda, R. J.

English

NASA Technical Reports Server

L -  55577 
RADIOACTIVE NUCLEI PRODUCTION 
FROM RELATIVELY ABUNDANT 
NATURAL ELEMENTS 
, 
GPO PRICE $ I 
I 
t CFSTI PRICE(S) $ 
I 
Hard copy (HC) II 00 
Microfiche (M F) \ s@ I 
I 
W 863 July 86 I 
JULY 1966 
GODDARD SPACE FLIGHT CENTER 
I GREENBELT, MARYLAND -x 
5 I e / q  (CODE1 
4 - sq-5 7 1 
bT 
[ -  
N67 11359 ITHRUI 
( A c Z c E ~ s l O N  NUMBER) 
, E  IPAdESl 
I i 
- ’ dRrOR TMX OR AD NUMBER) 
I 
https://ntrs.nasa.gov/search.jsp?R=19670002030 2020-03-24T02:40:49+00:00Z
RADIOACTIVE NUCLEI PRODUCTION FROM 
RELATNELY ABUNDANT NATURAL ELEMENTS 
by 
Robert J .  Janda 
July 1966 
GODDARD SPACE FLIGHT CENTER 
Greenbelt, Maryland 
RADIOACTIVE NUCLEI PRODUCTION FROM 
RELATIVELY ABUNDANT NATURAL ELEMENTS 
INTRODUCTION 
I 
The function of this data is to furnish a'guideline in evaluating potential radi- 
oactive nuclei production that could affect experiments or personnel in the God- 
dard Space Flight Center accelerator laboratory. The elements given in the 
table have been selected based upon the following criteria: 
a. Theoretical reaction threshold energies less than 17.0 MeV. 
b. Half-life time greater than 0 . 2  second. 
c. Natural element abundance greater than 1%. 
The use of the table is intended to serve accelerator personnel by estimating 
decay half-life for materials placed within the accelerator beam. The beam en- 
ergy and particle type are taken into account for each material in determining if 
the reaction goes to completion. Since activation cross-section data is not pro- 
vided, the table cannot provide reaction yields, it being a monumental task to 
obtain cross-section data for each threshold energy and particle type. 
Since the cross-section data is not readily obtainable, it does not necessar- 
ily mean the particular reactions shown in Table TI do or do not constitute a ra- 
diological hazard. The table shows that the potential reaction exists. 
DEFINITION 
The following list of definitions are headings as listed left to right in TableII. 
Target Nuclide: The element bombarded by the accelerated beam. The su- 
perscript refers to the atomic weight. Most elements exist in the form of sev- 
eral isotopes - some radioactive, some stable. 
Natural  Abundance: The percentage of the particular isotope which is found 
in any sample of the element. 
Radioactive Nuclei: The radioactive product formed when the accelerated 
beam interacts with the target nuclide. 
Production Scheme: The method of interaction to form the radioactive pro- 
duct. The first symbol in parentheses names the accelerated beam particle 
1 
which interacts with the target nuclide to yield the radioactive nuclei. The sec- 
ond symbol names the subatomic particle which is produced by the interaction in 
addition to  the radioactive nuclei. 
Decay Scheme: Defines the type of radiation produced by the radioactive 
nuclei during its decay. In some cases, there are multiple modes by which the 
radioactive nuclei may decay, and these are listed by their symbols. 
Half-Life: The time required for one half of all the nuclei in a given sample 
to decay exponentially. The activity never reaches zero, but becomes very 
small after several half lives. For example, after ten half lives the activity has 
reduced to - 0.1% of the original amount. 
Threshold Energy: The theoretical minimum energy in the center of mass, 
in million electron volts, an accelerated particle must have to interact with the 
target nucleus to produce a radioactive nucleus. In practice, the numbers 
quoted must be increased by 10% to 15% to give the corresponding laboratory en- 
ergies. For example, light nuclei with heavy bombarding particles will have a 
large center of mass correction. Conversely heavy nuclei with light bombarding 
particles will have a small correction. 
SYMBOLS 
The following symbols are used in Table 11: 
a : alpha particle 
p-- : electron emission 
/ j k  : positron emission 
y : Gamma ray or x-ray 
d : deuteron (heavy hydrogen nucleus) 
d : days (under half-life heading only) 
e : electron 
ex : exothermic (the accelerated particle does not need any energy to 
trigger the reaction) 
2 
*. 
h :hours 
IT : isometric transition (y-ray emission) 
K : K shell electron capture (y-ray emission) 
L : L shell electron capture (y-ray emission) 
m : minutes 
Mev : million electron volts 
n :neutron 
p : proton 
s : seconds 
t : triton (double heavy hydrogen nucleus) 
y :years  
TABLE UTILIZATION 
A typical example of using the tables would be in evaluating the activation 
hazard of a proton beam on an aluminum target. The relative hazard can be ob- 
tained as follows: 
1. Find A1 in Table I ,  note it is the seventh element listed in Table 11. 
2. Find A1 as the seventh element in Table 11. 
3. Choose the correct atomic weight of the element. (Typically, the highest 
percent of the natural abundance.) 
4. Seek the correct production scheme, in this case protons or  the (p, n) 
reaction. Note that neutrons should be anticipated if the threshold volt- 
age is reached. 
5.  Find the corresponding threshold energy and add 10% to be conservative. 
In our case, the final value would be about 6 . 1  MeV. 
3 
6. If the planned accelerated proton beam is to exceed 6.1 MeV, the result- 
ing decay half-life is 4.4 seconds. This element should not constitute a 
hazard since in an accelerator run the element will decay typically before 
the accelerator voltage is reduced to ground potential. 
Table I 
ORDER OF TABLE II ELEMENT LISTING 
1. Li 10. A r  19. Ge 
2. N 11. K 20. Z r  
3. 0 12. Ca 21. Sn 
I 4. Ne 13. Ti 22. Sb 
5. N a  14. C r  23. Ta 
i 6. Mg 15. Fe 24. Au 
7. AI 16. Ni 25. Pb 
8. Si 17. Cu 26. Th 
i 9. P 18. Zn 27. U 
4 
4 
Table II 
I I TARGET I NATURAL 1 RADIOACTIVE I PRODUCTION I DECAY I I THRESHOLD . NUCLIDE ABUNDANCE NUCLEI SCHEME SCHEME ENERGY 
5 
Table I1 (Continued) 
Table II (Continued) 
RADIOACTNE I PRODUCTION DECAY I HALF THRESHOLD 
ENERGY NUCLEI I SCHEME I SCUEME , LIFE 
I Ca44 
Ti46 
I Ti46 
Ti4’ 
Ti4’ 
Ti4’ 
Ti4’ 
Ti4’ 
Ti4’ 
Tis0 
Tis0 
~ r 5 O  
~ 1 - 5 0  
cr50 
~ 1 - 5 0  
cr50 
cr50 
crS0 
~r~~ 
~r~~ 
I C r 5 4  
8.0% 
74.0% 
5.5% 
5.3% 
4.4% 
84.0% 
9.5% 
2.4% 
20ca45 ( % Y )  13- 160.0d ex 
I 1 IT, K ; P 3 - , y  I 20.0s ; 8 5 . 0 d  I ex 
R-. Y 3.4d ex 
B+ 0.4s 8.17 
I I 
2 1 ~ 4 6  ( n , p )  IT. K B - . y  2 0 . 0 s  ; 85.0d  1.56 
2 2 ~ i 4 5  ( Y ? n )  p+; K 3 . l h  13.4 
16.2d 4.83 
21 sc4’ ( % P )  P - ,  Y 57.0m 1.19 I _. 
21sC4’ (Y.P)  8- ,Y 44.0h 11.4 
~r~~ 25mS ( a,,-) B-,  Y 2.6h ex 
~r~~ 2sMns7 ( t ,Y)  P->  Y 1.7m ex 
Fe54 6.0% P+ 0.18 s 9.70 
7 
Table I1 (Continued) 
a 
Table I1 (Continued) 
9 
Table I1 (Continued) 
~~ 
Ge7' 
Ge'O 
Ge" 
Ge7' 
Ge7' 
Ge7' 27.0% 
DECAY 1 zi: 1 THRESHOLD 
NUCLEI SCHEME ENERGY SCHEME I NATURAL RADIOACTIVE PRODUCTION I I I TARGET NUCLIDE ABUNDANCE 
~~ 
31 Ga7' ( e 9 Y )  P-. Y 21.0m 1.1 
33As7' ( P , Y )  P+, Y 62.0h  ex 
3 2 ~ e ~ '  ( n . y )  K 12.0d ex 
33As7' ( a , Y )  P', Y %.Oh ex 
33As73 ( t , Y )  K 76.0d ex 
.i.iAs72 ( p , n )  B + ,  Y 26.0h 5.20 
__ 
10 
4 
*119 
&119 
*120 
sn"' 
*120 
*122 
Table I1 (Continued) 
ex K 5.8d 8.5% 51 ( P.Y)  P+,K 17.0m 
IT 3.5m 
51Sb"' ( L Y )  B', K 2.8d 
P ,  Y 25.0~ 
( n , y )  P- 27.0h 
IT 3.5m 
51 ( 3 . Y )  K , P' 2.8d 
K 5.8d 
51Sb'20 ( p , n  1 p', K 17.0m 
4.8 50 ( n , r )  p-3 Y 40.0m 
&120 
ex 
ex 32.5% wSn'21 
.&"2 ex 
3.50 
ex 0-. Y 130.0d *123 
11 
Table 11 (Continued) 
0.9 0: Y 130.0d ( e , r )  p-3 Y 40.0m 
IT 21.0m 
~ 1 2 3  43.0% 
S 1 2 3  51Sb’24 ( n . 7 )  p-. Y 1.3m ex o-. Y 60.0d 
p-! Y 130.0 d 0.6  
- 
5 0 ~ n 1 2 3  ( n , p )  p-s Y 40.0m ~ 1 2 3  
___. 
Tal8’ 99.99% 7 2 ~ f ” ’  ( n . p )  p-, 2 46.0 d 0.20 
8.0h 7.7 
73Tdeo ( r , n )  % Ta la’ 
0.00 IT ; p-.. 2.8h; 82.0m 
78 ( n , p )  P: Y 19.0h 
pt197 AuI9’ 100.0% 
0.30 IT ; p-. Y 2.8h ; 82 .0m 
78 ( e , r )  P-, Y 19.0h 
pt197 Au 19’ 
12 
Table II (Continued) 
ThZ3‘ 
Th232 
$38 
. 
100.0% 9 1 ~ a 2 3 2  (p .n  ) p-. Y 1 .3d  1.16 
goThZ3’ (,,,n) R-.Y 26.0h 6.4 
99.3% g3Nb238 (p ,n  1 p-. Y 2 . l d  0.90 
TARGET 
I I I (Y,P) F . 7  39.0m $38 
~ 
NATURAL 
ABUNDANCE 
21.0% 
7.5 
, 52.096 
RADIOAC T N E  
NUCLEI 
83Bi207 
8 1 ~ 1 2 0 7  
81T1206 
81~1207 
PRODUCTION DECAY HALF 
SCHEME SCHEME LIFE 
(Psn ) K 30.03’ 
( n . P )  P - , Y  4.8m 
(Y,P)  P- 4.2m 
(Y,P)  P-.Y 4.8m 
ENERGY 
8.0 
ADDITIONAL REFERENCES TO OBTAIN NUCLEAR DATA: 
1. National Bureau of Standards 
Circular #499 - Nuclear Data 
September 1, 1950 
2. Table of Isotopes 
Seaborg, G. T.  & Perlman, I. 
Rev. of Modern Physics 
Vol. 20, No. 4, October 1948 
ACKNOWLEDGEMENTS 
The author wishes to acknowledge and thank Messrs. Eric Katz and Jesse 
Sabo for the assistance in compilation of the data. 
13 


Radioactive nuclei production from relatively abundant natural elements

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server