Americium-244

Properties and data of the isotope ²⁴⁴Am.

Content

General data

Name of the isotope:Americium-244; Am-244Symbol:²⁴⁴Am or 24495AmMass number A:244 (= number of nucleons)Atomic number Z:95 (= number of protons)Neutrons N:149Isotopic mass:244.0642830(16) u (atomic weight of Americium-244)Nuclide mass:244.0121751 u (calculated nuclear mass without electrons)Mass excess:59.87923 MeVMass defect:1.970167524 u (per nucleus)Nuclear binding energy:1835.1992276 MeV (per nucleus)
7.52130831 MeV (average binding energy per nucleon)Separation energy:S_N = 5.3672(16) MeV (first neutron)
S_P = 5.1644(26) MeV (first proton)Half-life:10.1(1) hDecay constant λ:2.001233342649 × 10^-6 s^-1Specific activity α:4.939225034030 × 10⁺¹⁵ Bq g^-1
133492.56848732 Ci g^-1Spin and parity:
(nuclear angular momentum)(6-)Year of discovery:1950

Radioactive Decay

Half-life T_½ = 10.1(1) h (hours) respectively 3.46360 × 10⁵ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β^-	²⁴⁴Cm	100 %	1.4273(10) MeV

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
^244mAm	86.5(16) keV	26 min	1+

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 149) and isobaric (same nucleon number A = 244) with Americium-244. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 149	Isobar A = 244
91	²⁴⁰Pa
92	²⁴¹U
93	²⁴²Np	²⁴⁴Np
94	²⁴³Pu	²⁴⁴Pu
95	²⁴⁴Am	²⁴⁴Am
96	²⁴⁵Cm	²⁴⁴Cm
97	²⁴⁶Bk	²⁴⁴Bk
98	²⁴⁷Cf	²⁴⁴Cf
99	²⁴⁸Es	²⁴⁴Es
100	²⁴⁹Fm	²⁴⁴Fm
101	²⁵⁰Md	²⁴⁴Md
102	²⁵¹No
103	²⁵²Lr
104	²⁵³Rf