Samarium-153m

Properties and data of the isotope ¹⁵³Sm.

Content

General data

Name of the isotope:Samarium-153m; Sm-153mSymbol:¹⁵³Sm or 15362SmMass number A:153 (= number of nucleons)Atomic number Z:62 (= number of protons)Neutrons N:91Isotopic mass:152.9221036(11) u (atomic weight of Samarium-153m)
Excitation energy: 98.39(10) keVNuclide mass:152.8880943 u (calculated nuclear mass without electrons)Mass excess:-72.56003 MeVMass defect:1.35155574 u (per nucleus)Nuclear binding energy:1258.96606248 MeV (per nucleus)
8.22853636 MeV (average binding energy per nucleon)Half-life:10.6(3) msDecay constant λ:65.391243449051 s^-1Specific activity α:2.590758414846 × 10⁺²³ Bq g^-1
7002049769854.3 Ci g^-1Spin and parity:
(nuclear angular momentum)11/2-

Radioactive Decay

Half-life T_½ = 10.6(3) ms respectively 1.06 × 10^-2 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
Iso	¹⁵³Sm	100 %		0.0329(1) MeV 98.39(10) %

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
¹⁵³Sm		46.284(4) h	3/2+

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 91) and isobaric (same nucleon number A = 153) with Samarium-153m. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 91	Isobar A = 153
52	¹⁴³Te
53	¹⁴⁴I
54	¹⁴⁵Xe
55	¹⁴⁶Cs
56	¹⁴⁷Ba	¹⁵³Ba
57	¹⁴⁸La	¹⁵³La
58	¹⁴⁹Ce	¹⁵³Ce
59	¹⁵⁰Pr	¹⁵³Pr
60	¹⁵¹Nd	¹⁵³Nd
61	¹⁵²Pm	¹⁵³Pm
62	¹⁵³Sm	¹⁵³Sm
63	¹⁵⁴Eu	¹⁵³Eu
64	¹⁵⁵Gd	¹⁵³Gd
65	¹⁵⁶Tb	¹⁵³Tb
66	¹⁵⁷Dy	¹⁵³Dy
67	¹⁵⁸Ho	¹⁵³Ho
68	¹⁵⁹Er	¹⁵³Er
69	¹⁶⁰Tm	¹⁵³Tm
70	¹⁶¹Yb	¹⁵³Yb
71	¹⁶²Lu	¹⁵³Lu
72	¹⁶³Hf	¹⁵³Hf
73	¹⁶⁴Ta
74	¹⁶⁵W
75	¹⁶⁶Re
76	¹⁶⁷Os
77	¹⁶⁸Ir
78	¹⁶⁹Pt
79	¹⁷⁰Au
80	¹⁷¹Hg