This table presents an evaluated set of values for the experimental quantities that characterize the decay of radioactive nuclides. A list of the major references used in this evaluation is given below. When uncertainties are not listed, they are assumed to be five or less in the last digit quoted. If the uncertainty in the value exceeds five in the last digit, the value is preceded by an approximate sign.
For quasi-stable nuclides, the measured width, Γ, of the resonance is given. To estimate the approximate half-life, the Heisenberg relationship may be used: the half-life = 4.56 × 10-22 seconds / Γ (MeV). The effective literature cutoff date for data in this edition of the table is October 2019.
This table in the Print Edition of the CRC Handbook is condensed from this full table.. The print table includes all stable isotopes and the radioactive isotopes with lifetimes of a few hours or longer, as well as selected shorter-lived isotopes of the transuranium elements.
Column definitions for the table are as follows.
Column heading | Definition |
Elem. or Isot. | For elements, the atomic number and chemical symbol are listed; for nuclides, the mass number and chemical symbol are listed; isomers are indicated by the addition of m, m1, or m2 |
Natural abundance | Abundance of an isotope in normal terrestrial samples of an element, in atom percent |
Atomic mass or weight | Atomic mass relative to 12C = 12 (exact); atomic weight of elements is given on the same scale |
Half-life/Resonance width | Half-life in decimal notation. µs = microseconds; ms = milliseconds; s = seconds; m = minutes; h = hours; d = days; and a = years; for quasi-stable nuclides
Resonance width is the measured width at half-maximum of the energy resonance, in MeV |
Decay mode, Abs. intens., Energy | Decay modes are α = alpha particle emission; β = negative beta emission; β+ = positron emission; ec = orbital electron capture; IT = isomeric transition from upper to lower isomeric state; n = neutron emission; p = proton emission; sf = spontaneous fission; ββ, ECEC, 2p, 2n, 3n = double beta, double EC, two-proton and multiple-neutron decay
Absolute intensity, in %, when reported Total disintegration energy in MeV units |
Particle energy/ Intensity | End point energies of beta transitions and discrete energies of alpha particles, neutrons, and protons, in MeV
Intensities, in percent |
Spin | Nuclear spin or angular momentum of the nuclides, in units of h/2π; parity is positive or negative |
Nuclear magnetic mom. | Magnetic dipole moments, in units of nuclear magneton; an absolute value is indicated in the absence of a positive or a negative sign |
Elect. quadr. mom. | Electric quadrupole moments, in barn (10-24 cm2); an absolute value is indicated in the absence of a positive or a negative sign |
γ-Energy/Intensity | Gamma ray energies, in MeV
Intensities, in percent Annihilation radiation (ann.rad.) refers to the 511.006 keV photons emitted in the annihilation of positrons in matter |
The following references represent the major sources of the nuclear data presented, along with subsequent published journal articles and reports:
This research was carried out under the auspices of the U.S. Department of Energy Contract No. DE-AC02-98CH10886. The author is at Brookhaven National Laboratory, Upton, NY, and can be contacted at [email protected].
Element | Elem. or Isot. | Natural abundance/Atom % | Atomic mass or weight | Half-life/Resonance width/MeV | Decay mode, Abs. intens., Energy/mode, %, MeV | Particle energy/Intensity/MeV, % | Spin/h/2π | Nuclear magnetic mom./nm | Elect. quadr. mom./b | γ-Energy/Intensity/MeV, % |
Continued on next page... | ||||||||||
Neutron | on | 1.008664916 | 610.5 s | β- /0.78235 | 0.782/100. | 1/2+ | -1.913043 | |||
Neutron | on | β-, γ | / 0.0031 | |||||||
Hydrogen | 1H | 1.00784-1.00811 | ||||||||
Hydrogen | 1H | 99.972 - 99.999 | 1.007825032 | >2.8 ×1023 a | 1/2+ | +2.7928473 | ||||
Hydrogen | 2H | 0.001-0.028 | 2.014101778 | 1+ | +0.8574382 | +2.86 mb | ||||
Hydrogen | 3H | 3.016049282 | 12.31 a | β-/0.01859 | 0.01860/100. | 1/2+ | +2.9789624 | |||
Hydrogen | 4H | 4.026 | Γ = 1.2 | n/ | /100 | 2- | ||||
Hydrogen | 5H | 5.035 | Γ < 0.5 | n/ | /100 | (1/2+) | ||||
Hydrogen | 6H | 6.045 | Γ ~ 6. | n/ | (2-) | |||||
Hydrogen | 7H | 7.05 | Γ ~ 0.1 | |||||||
Helium | 2He | 4.002602(2) | ||||||||
Helium | 3He | 0.0002(2) | 3.016029323 | 1/2+ | -2.127750 | |||||
Helium | 4He | 99.9998(2) | 4.0026032541 | 0+ | ||||||
Helium | 5He | 5.0121 | Γ = 0.60(2) | n, α | 3/2- | |||||
Helium | 6He | 6.0188859 | 0.8069 s | β-/3.508 | 3.510/100. | 0+ | ||||
Helium | 6He | β, d | 0.35/0.00017 | |||||||
Helium | 7He | 7.02799 | Γ ~ 0.19 | n | (3/2)- | |||||
Helium | 8He | 8.033934 | 0.119 s | β-/10.65 | /84. | 0+ | 0.9807/84. | |||
Helium | 8He | β- n/ | /16. | 0.4776/5. |