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Appendix B Selected Radioactive Isotopes

Decay modes are   α , β-, β+, electron capture (EC) and isomeric transition (IT). EC results in the same daughter nucleus as would β+ decay. IT is a transition from a metastable excited state. Energies for \beta ^{\pm} decays are the maxima; average energies are roughly one-half the maxima.

Isotope t 1/2 DecayMode(s) Energy(MeV) Percent \gamma-Ray Energy(MeV) Percent
3H 12.33 y β- 0.0186 100%
14C 5730 y β- 0.156 100%
13N 9.96 min β+ 1.20 100%
22Na 2.602 y β+ 0.55 90% γ 1.27 100%
32P 14.28 d β- 1.71 100%
^{35} \textbf{S} 87.4 d β- 0.167 100%
^{36} \textbf{Cl} 3.00 \times 10^5 \text{y} β- 0.710 100%
^{40} \textbf{K} 1.28 \times 10^9 \text{y} β- 1.31 89%
^{43} \textbf{K} 22.3 h \beta ^{-} 0.827 87% \gamma \;\text{s} 0.373 87%
0.618 87%
^{45} \textbf{Ca} 165 d \beta ^{-}­ 0.257 100%
^{51} \textbf{Cr} 27.70 d EC \gamma 0.320 10%
^{52} \textbf{Mn} 5.59d \beta ^{+} 3.69 28% \gamma \;\text{s} 1.33 28%
1.43 28%
^{52} \textbf{Fe} 8.27 h \beta ^{+} 1.80 43% 0.169 43%
0.378 43%
^{59} \textbf{Fe} 44.6 d \beta ^{-} 0.273 45% \gamma \;\text{s} 1.10 57%
0.466 55% 1.29 43%
^{60} \textbf{Co} 5.271 y \beta ^{-}­ 0.318 100% \gamma \;\text{s} 1.17 100%
1.33 100%
^{65} \textbf{Zn} 244.1 d EC \gamma 1.12 51%
^{67} \textbf{Ga} 78.3 h EC \gamma \;\text{s} 0.0933 70%
0.185 35%
0.300 19%
others
^{75} \textbf{Se} 118.5 d EC \gamma \;\text{s} 0.121 20%
0.136 65%
0.265 68%
0.280 20%
others
^{86} \textbf{Rb} 18.8 d \beta ^{-} 0.69 9% \gamma 1.08 9%
1.77 91%
^{85} \textbf{Sr} 64.8 d EC \gamma 0.514 100%
^{90} \textbf{Sr} 28.8 y \beta ^{-}­ 0.546 100%
^{90} \textbf{Y} 64.1 h \beta ^{-}­ 2.28 100%
^{99m} \textbf{Tc} 6.02 h IT \gamma 0.142 100%
^{113m} \textbf{In} 99.5 min IT \gamma 0.392 100%
^{123} \textbf{I} 13.0 h EC \gamma 0.159 \approx 100 \%
^{131} \textbf{I} 8.040 d \beta ^{-} 0.248 7% \gamma \;\text{s} 0.364 85%
0.607 93% others
others
^{129} \textbf{Cs} 32.3 h EC \gamma \;\text{s} 0.0400 35%
0.372 32%
0.411 25%
others
^{137} \textbf{Cs} 30.17 y \beta ^{-} \;\text{s}­ 0.511 95% γ 0.662 95%
1.17 5%
^{140} \textbf{Ba} 12.79 d β- 1.035 ≈100 \gamma \;\text{s} 0.030 25%
0.044 65%
0.537 24%
others
^{198} \textbf{Au} 2.696 d \beta ^{-}­ 1.161 ≈100% γ 0.412 \approx 100 \%
^{197} \textbf{Hg} 64.1 h EC γ 0.0733 100%
^{210} \textbf{Po} 138.38 d \alpha 5.41 100%
^{226} \textbf{Ra} 1.60 \times 10^3 \text{y} \alpha \;\text{s} 4.68 5% γ 0.186 100%
4.87 95%
^{235} \textbf{U} 7.038 \times 10^8 \text{y} \alpha 4.68 \approx 100 \% \gamma \;\text{s} numerous <0.400%
^{238} \textbf{U} 4.468 \times 10^9 \text{y} \alpha \;\text{s} 4.22 23% γ 0.050 23%
4.27 77%
237Np 2.14 x 106 y α s numerous  γ s numerous <0.250%
4.96 (max.)
239Pu 2.41 x  104 y α s 5.19 11% γ s 7.5 x 10-5 73%
5.23 15% 0.013 15%
5.24 73% 0.052 10%
others
243Am 7.37×103 y α s Max. 5.44 γ s 0.075
5.37 88% others
5.32 11%
others
Table 2. Selected Radioactive Isotopes

 

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Douglas College Physics 1207 Copyright © August 22, 2016 by OpenStax is licensed under a Creative Commons Attribution 4.0 International License, except where otherwise noted.