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Chapter: 4 Atomic and nuclear physics
    Section: 4.6 Radioactive elements
        SubSection: 4.6.1 Table of nuclides



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Version 2.0
Updated: 21 December 2010
Previous versions

  1. Index of Parts

Sources of data

1 - ENSDF datasets, as maintained by the International Network of Nuclear Structure and Decay Data Evaluators and the US National Nuclear Data Center, Brookhaven National Laboratory.
2 - Laboratoire National Henri Becquerel, Decay Data Evaluation Project (DDEP).
3 - Jagdish K. Tuli, Nuclear Wallet Cards, 7th edition, April 2005, Brookhaven National Laboratory, US National Nuclear Data Center.
4 - S. F. Mughabghab, Atlas of Neutron Resonances, Elsevier, 2006.
5 - RADLIST program, Thomas W. Borrows, 1988, Brookhaven National Laboratory, US National Nuclear Data Center.

Data compilation

Assembled by Alan Nichols and Marco Verpelli, Nuclear Data Section, Division of Physical and Chemical Sciences, Department of Nuclear Sciences and Applications, International Atomic Energy Agency, Vienna, Austria.

Compiled and checked, September to December 2007. Introduction of DDEP half-lives in October 2008.

Nuclide selection criteria

The table contains all nuclides present within ENSDF, DDEP (LNHB Web site) and the Nuclear Wallet Cards for which a half-life or natural abundance is reported. Nuclides for which only the level width is known are not included.


Uncertainties are shown in italics, and are expressed in terms of the last digit(s) of the recommended value. For example:  686.080 6 means 686.080 ± 0.006, 0.037 3 means 0.037 ± 0.003, and 1.97 +131 -19 means 1.97 +1.31 and -0.19.


Column 1: Nuclide
Nuclide names are of the form Z, Element name, and A(mi) where mi denotes an isomeric state.
Nuclides are listed in order of:
1 - increasing atomic number Z,
2 - increasing mass number A,
3 - mass excess Δ (see column 3).

Some nuclides have ill-defined Δ and possess the same values for Z, A and Δ, which prevents any distinction being made between ground and metastable state(s) on the basis of the energies of these levels. Under these circumstances, ground or metastable states cannot be distinguished and these states remain unassigned within the data file (for example, 81-Tl-190 is ill-defined as either Jπ = 2(-) or 7(+); and 83-Bi-194m is ill-defined as either Jπ = (10-) or Jπ = (6+, 7+)).

Column 2: Jπ
Spin and parity assignments without and with parentheses are based on strong and weak arguments, respectively. See the introductory pages of any issue of Nuclear Data Sheets for descriptions of strong and weak arguments for Jπ assignments.

Column 3: Mass excess
Mass excesses are given in MeV, with 12C mass excess equal to zero by definition. Values for isomers are obtained by adding the excitation energy to the ground state mass excess. Whenever the excitation energy is not known, the mass excess for the next lower isomer is given. An appended “syst” denotes that the value is obtained from systematics.

Column 4: Natural abundance or half-life
Abundances are in bold font. DDEP data have precedence on ENSDF data. An appended “syst” is present when a limit or an approximate value is obtained from systematics.
The adopted half-life units are as follows:


year   (1 year = 31 556 926 seconds)








10-3 second


10-6 second


10-9 second


10-12 second

Column 5: Decay modes
Decay modes are listed in order of decreasing strength, followed by the percentage branching. An expected but not observed mode of decay is followed by “?”.
Explanation of symbols:


β- decay.


ε (electron capture), and/or ε + β+, and/or β+.


isomeric transition.


neutron decay.


proton decay.


alpha decay.


spontaneous fission.

-, 3α, …

double β-, decay by means of three α emission, ...

β-n, β-p, …

delayed n, p, … emission following β- decay.

εn, εp, …

delayed n, p, … emission following ε decay.

Column 6: Major Radiations
The quoted beta radiation energy is the end-point energy obtained by processing ENSDF datasets with RADLIST.
Selection criteria for the principal radiations:

Beta radiation:  

most energetic branch with an intensity greater than 0.5 % is listed first, followed in order of decreasing energy by a maximum of two other branches with intensities greater than 20 %.

Alpha radiation:  

four most intense branches with intensities greater than 0.5 % are listed in order of energy.

Gamma radiation:  

two most intense branches with intensities greater than 0.5 % are listed in order of intensity.

Column 7 : Thermal Neutron Cross-section
Data are expressed in barns, and are taken from the Atlas of Neutron Resonances.


neutron radiative capture measured in a Maxwellian flux.

σγm , σγm + g

neutron radiative capture measured with reactor neutrons, leading to the formation of ground (g) and metastable (m) states.


neutron fission cross section.


neutron cross section for proton emission.


neutron absorption cross section.


neutron total cross section.

The Kaye and Laby Table of Nuclides in the 16th edition of the book was over 100 pages long. So as you can imagine it was a very large table. To minimise browser related problems with such a large page, we have split the table into parts. Please use the links below to view parts of the table.


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