Actinide
Isotopes

Actinide

Section Title: Isotopes
Table Section Text: None

Isotope	Half-life	Probability of spontaneous fission in %	Emission energy (MeV) (yield in %)	Specific activity (Bq/kg) 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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