Actinide
Isotopes
Table:
Nuclear properties of isotopes of the most important transplutonium isotopes[57][58][59]

Isotope

Half-life

Probability of
spontaneous
fission in %

Emission energy
(MeV) (yield in %)

Specific activity (Bq/kg)[60] of

α

γ

α, β-particles

fission

241Am
432.2(7) y
4.3(18)×10−10
5.485 (84.8)
5.442 (13.1)
5.388 (1.66)
0.059 (35.9)
0.026 (2.27)
1.27×1014
546.1

243Am
7.37(4)×103 y
3.7(2)×10−9
5.275 (87.1)
5.233 (11.2)
5.181 (1.36)
0.074 (67.2)
0.043 (5.9)
7.39×1012
273.3

242Cm
162.8(2) d
6.2(3)×10−6
6.069 (25.92)
6.112 (74.08)
0.044 (0.04)
0.102 (4×10−3)
1.23×1017
7.6×109

244Cm
18.10(2) y
1.37(3)×10−4
5.762 (23.6)
5.804 (76.4)
0.043 (0.02)
0.100 (1.5×10−3)
2.96×1015
4.1×109

245Cm
8.5(1)×103 y
6.1(9)×10−7
5.529 (0.58)
5.488 (0.83)
5.361 (93.2)
0.175 (9.88)
0.133 (2.83)
6.35×1012
3.9×104

246Cm
4.76(4)×103 y
0.02615(7)
5.343 (17.8)
5.386 (82.2)
0.045 (19)
1.13×1013
2.95×109

247Cm
1.56(5)×107 y
—
5.267 (13.8)
5.212 (5.7)
5.147 (1.2)
0.402 (72)
0.278 (3.4)
3.43×109
—

248Cm
3.48(6)×105 y
8.39(16)
5.034 (16.52)
5.078 (75)
—
1.40×1011
1.29×1010

249Bk
330(4) d
4.7(2)×10−8
5.406 (1×10−3)
5.378 (2.6×10−4)
0.32 (5.8×10−5)
5.88×1016
2.76×107

249Cf
351(2) y
5.0(4)×10−7
6.193 (2.46)
6.139 (1.33)
5.946 (3.33)
0.388 (66)
0.333 (14.6)
1.51×1014
7.57×105

250Cf
13.08(9) y
0.077(3)
5.988 (14.99)
6.030 (84.6)
0.043
4.04×1015
3.11×1012

251Cf
900(40) y
?
6.078 (2.6)
5.567 (0.9)
5.569 (0.9)
0.177 (17.3)
0.227 (6.8)
5.86×1013
—

252Cf
2.645(8) y
3.092(8)
6.075 (15.2)
6.118 (81.6)
0.042 (1.4×10−2)
0.100 (1.3×10−2)
1.92×1016
6.14×1014

254Cf
60.5(2) d
≈100
5.834 (0.26)
5.792 (5.3×10−2)
—
9.75×1014
3.13×1017

253Es
20.47(3) d
8.7(3)×10−6
6.540 (0.85)
6.552 (0.71)
6.590 (6.6)
0.387 (0.05)
0.429 (8×10−3)
9.33×1017
8.12×1010

254Es
275.7(5) d
< 3×10−6
6.347 (0.75)
6.358 (2.6)
6.415 (1.8)
0.042 (100)
0.034 (30)
6.9×1016
—

255Es
39.8(12) d
0.0041(2)
6.267 (0.78)
6.401 (7)
—
4.38×1017(β)
3.81×1016(α)
1.95×1013

255Fm
20.07(7) h
2.4(10)×10−5
7.022 (93.4)
6.963 (5.04)
6.892 (0.62)
0.00057 (19.1)
0.081 (1)
2.27×1019
5.44×1012

256Fm
157.6(13) min
91.9(3)
6.872 (1.2)
6.917 (6.9)
—
1.58×1020
1.4×1019

257Fm
100.5(2) d
0.210(4)
6.752 (0.58)
6.695 (3.39)
6.622 (0.6)
0.241 (11)
0.179 (8.7)
1.87×1017
3.93×1014

256Md
77(2) min
—
7.142 (1.84)
7.206 (5.9)
—
3.53×1020
—

257Md
5.52(5) h
—
7.074 (14)
0.371 (11.7)
0.325 (2.5)
8.17×1019
—

258Md
51.5(3) d
—
6.73
—
3.64×1017
—

255No
3.1(2) min
—
8.312 (1.16)
8.266 (2.6)
8.121 (27.8)
0.187 (3.4)
8.78×1021
—

259No
58(5) min
—
7.455 (9.8)
7.500 (29.3)
7.533 (17.3)
—
4.63×1020
—

256Lr
27(3) s
< 0.03
8.319 (5.4)
8.390 (16)
8.430 (33)
—
5.96×1022
—

257Lr
646(25) ms
—
8.796 (18)
8.861 (82)
—
1.54×1024
—

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