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 β± decays are the maxima; average energies are roughly one-half the maxima.

Table B1 Selected Radioactive Isotopes
Isotope t 1/2 DecayMode(s)Energy(MeV)Percentγ-Ray Energy(MeV)Percent
3 H 12.33 yβ− ­0.0186100%
14 C 5730 y β − 0.156100%
13 N 9.96 min β + 1.20100%
22 Na 2.602 y β + 0.5590% γ 1.27100%
32 P 14.28 d β − 1.71100%
35 S 87.4 dβ− ­0.167100%
36 Cl 3 . 00 × 10 5 y β − 0.710100%
40 K 1 . 28 × 10 9 y β − 1.3189%
43 K 22.3 h β − 0.82787% γ s 0.37387%
0.61887%
45 Ca 165 dβ− ­0.257100%
51 Cr 27.70 dEC γ 0.32010%
52 Mn 5.59d β + 3.6928% γ s 1.3328%
1.4328%
52 Fe 8.27 h β + 1.8043%0.16943%
0.37843%
59 Fe 44.6 d β − s 0.27345% γ s 1.1057%
0.46655%1.2943%
60 Co 5.271 yβ− ­0.318100% γ s 1.17100%
1.33100%
65 Zn 244.1 dEC γ 1.1251%
67 Ga 78.3 hEC γ s 0.093370%
0.18535%
0.30019%
others
75 Se 118.5 dEC γ s 0.12120%
0.13665%
0.26568%
0.28020%
others
86 Rb 18.8 d β − s 0.699% γ 1.089%
1.7791%
85 Sr 64.8 dEC γ 0.514100%
90 Sr 28.8 yβ− ­0.546100%
90 Y 64.1 hβ− ­2.28100%
99m Tc 6.02 hIT γ 0.142100%
113m In 99.5 minIT γ 0.392100%
123 I 13.0 hEC γ 0.159 ≈100%
131 I 8.040 d β − s 0.2487% γ s 0.36485%
0.60793%others
others
129 Cs 32.3 hEC γ s 0.040035%
0.37232%
0.41125%
others
137 Cs 30.17 yβ−s ­0.51195% γ 0.66295%
1.175%
140 Ba 12.79 d β − 1.035 ≈100% γ s 0.03025%
0.04465%
0.53724%
others
198 Au 2.696 dβ− ­1.161 ≈100% γ 0.412 ≈100%
197 Hg 64.1 hEC γ 0.0733100%
210 Po 138.38 d α 5.41100%
226 Ra 1 . 60 × 10 3 y α s 4.685% γ 0.186100%
4.8795%
235 U 7 . 038 × 10 8 y α 4.68 ≈100% γ s numerous<0.400%
238 U 4 . 468 × 10 9 y α s 4.2223% γ 0.05023%
4.2777%
237 Np 2 . 14 × 10 6 y α s numerous γ s numerous<0.250%
4.96 (max.)
239 Pu 2 . 41 × 10 4 y α s 5.1911% γ s 7 . 5 × 10 − 5 73%
5.2315%0.01315%
5.2473%0.05210%
others
243 Am 7 . 37 × 10 3 y α s Max. 5.44 γ s 0.075
5.3788%others
5.3211%
others