Americium-241
Properties and data of the isotope 241Am.
Americium-241 is the artificial radioisotope of the element Americium, whose atomic nucleus has 146 neutrons in addition to the element-specific 95 protons, resulting in a mass number of 241: 241Am.
See also: list of Americium isotopes.
General data
Name of the isotope:Americium-241; Am-241Symbol:241Am or 24195AmMass number A:241 (= number of nucleons)Atomic number Z:95 (= number of protons)Neutrons N:146Isotopic mass:241.0568273(12) u (atomic weight of Americium-241)Nuclide mass:241.0047194 u (calculated nuclear mass without electrons)Mass excess:52.93429 MeVMass defect:1.951628476 u (per nucleus)Nuclear binding energy:1817.93021562 MeV (per nucleus)
7.5432789 MeV (average binding energy per nucleon)Separation energy:SN = 6.647(14) MeV (first neutron)
SP = 4.47996(17) MeV (first proton)Cross section:σ(n.γ) = 628(22) barn (thermal neutron capture cross-section)
σ(n.f) = 3.15(10) b (gap cross-section)Half-life:432.6(6) aDecay constant λ:5.08079296727 × 10-11 s-1Specific activity α:126959547423.58 Bq g-1
3.4313391195562 Ci g-1Spin and parity:
(nuclear angular momentum)5/2-Magnetic dipole moment:μ(μN) = + 1.58(1)Charge radius:5.8928(42) femtometer fmYear of discovery:1949
Radioactive Decay
Half-life T½ = 432.6(6) a respectively 1.36425 × 1010 seconds s.
Decay mode | Daughter | Probability | Decay energy | γ energy (intensity) |
---|
α | 237Np | ca. 100 % | 5.63782(12) MeV | 59.5409(1) keV 35.9(4) % 0.02138(22) MeV/Bq-s |
SZ | div | trace | | |
Parent Nuclides
Direct parent isotopes are: 245Bk, 241Cm, 241Pu.
NMR data
Nuclear magnetic properties of the NMR active Nuclide 241Am
Isotope:241Am-NMRQuantity:Does not occur in nature!Spin:5/2-Nuclearmagnetic moment
μ/μN:+ 1.58(1)Gyromagnetic ratio γ:1.04 · 107 rad T-1 s-1Nuclear g-factor:gl = 0.632Quadrupole moment Q:+4.34(5) barn (100 fm2)Line width parameter (factor):l = 60273.92 fm4
Nuclear Isomers
Nuclear isomers or excited states with the activation energy in keV related to the ground state.
Nuclear Isomer | Excitation Energy | Half-life | Spin |
---|
241mAm | 2200(100) keV | 1.2(3) μs | |
Isotones and Isobars
The following table shows the atomic nuclei that are isotonic (same neutron number N = 146) and isobaric (same nucleon number A = 241) with Americium-241. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.
Z | Isotone N = 146 | Isobar A = 241 |
87 | 233Fr | |
88 | 234Ra | |
89 | 235Ac | |
90 | 236Th | |
91 | 237Pa | |
92 | 238U | 241U |
93 | 239Np | 241Np |
94 | 240Pu | 241Pu |
95 | 241Am | 241Am |
96 | 242Cm | 241Cm |
97 | 243Bk | 241Bk |
98 | 244Cf | 241Cf |
99 | 245Es | 241Es |
100 | 246Fm | 241Fm |
101 | 247Md | |
External data and identifiers
CAS:14596-10-2InChI Key:LXQXZNRPTYVCNG-YPZZEJLDSA-NSMILES:[241Am]PubChem:ID 104726Adopted Levels, Gammas:NuDat 241Am
Literature and References
[1] - Shoji Nakamura et al.:
Thermal-Neutron Capture Cross Section and Resonance Integral of Americium-241.
In: Journal of Nuclear Science and Technology, (2007), DOI 10.1080/18811248.2007.9711399.
Last update: 2023-04-15
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