Cerium-155

Properties and data of the isotope ¹⁵⁵Ce.

Contents

General Data

Radioactive Decay

Parent Nuclides

Isotones und Isobares

Literature

Cerium-155 is a radioisotope of the chemical element cerium, which has 97 neutrons in its atomic nucleus in addition to the element-specific 58 protons; the sum of the number of these atomic nucleus building blocks results in a mass number of 155. The very short-lived, only artificially produced, unstable and thus radioactive nuclide has no practical significance; the study of ¹⁵⁵Ce is exclusively for academic purposes.

The neutron-rich isotope cerium-155 was first produced in 1994 by fission of a uranium-235 beam with an energy of 750 MeV per nucleon on a lead-208 target [1].

See also: List of individual Cerium isotopes (and general data sources).

General data

Name of the isotope:Cerium-155; Ce-155Symbol:¹⁵⁵Ce or 15558CeMass number A:155 (= number of nucleons)Atomic number Z:58 (= number of protons)Neutrons N:97Isotopic mass:154.94871(32) u (atomic weight of Cerium-155)Nuclide mass:154.9168946 u (calculated nuclear mass without electrons)Mass excess:-47.77633 MeVMass defect:1.345638708 u (per nucleus)Nuclear binding energy:1253.45438267 MeV (per nucleus)
8.08680247 MeV (average binding energy per nucleon)Separation energy:S_N = 3.632(361) MeV (first neutron)
S_P = 13.539(424) MeV (first proton)Half-life:313(7) msDecay constant λ:2.2145277334184 s^-1Specific activity α:8.659868797975 × 10⁺²¹ Bq g^-1
234050508053.38 Ci g^-1Spin and parity:
(nuclear angular momentum)(5/2-)Year of discovery:1994

Radioactive Decay

Half-life T_½ = 313(7) ms respectively 3.13 × 10^-1 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β^-	¹⁵⁵Pr	100 %	7.640(300) MeV
β^-, n		?	2.25(32) MeV

Parent Nuclides

Direct parent isotope is: ¹⁵⁵La.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 97) and isobaric (same nucleon number A = 155) with Cerium-155. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 97	Isobar A = 155
56	¹⁵³Ba
57	¹⁵⁴La	¹⁵⁵La
58	¹⁵⁵Ce	¹⁵⁵Ce
59	¹⁵⁶Pr	¹⁵⁵Pr
60	¹⁵⁷Nd	¹⁵⁵Nd
61	¹⁵⁸Pm	¹⁵⁵Pm
62	¹⁵⁹Sm	¹⁵⁵Sm
63	¹⁶⁰Eu	¹⁵⁵Eu
64	¹⁶¹Gd	¹⁵⁵Gd
65	¹⁶²Tb	¹⁵⁵Tb
66	¹⁶³Dy	¹⁵⁵Dy
67	¹⁶⁴Ho	¹⁵⁵Ho
68	¹⁶⁵Er	¹⁵⁵Er
69	¹⁶⁶Tm	¹⁵⁵Tm
70	¹⁶⁷Yb	¹⁵⁵Yb
71	¹⁶⁸Lu	¹⁵⁵Lu
72	¹⁶⁹Hf	¹⁵⁵Hf
73	¹⁷⁰Ta	¹⁵⁵Ta
74	¹⁷¹W
75	¹⁷²Re
76	¹⁷³Os
77	¹⁷⁴Ir
78	¹⁷⁵Pt
79	¹⁷⁶Au
80	¹⁷⁷Hg
81	¹⁷⁸Tl
82	¹⁷⁹Pb