20Mg

β+-Decay Evaluated Data



Measurements
1978MOZL: 20Mg; measured σ(Ep) for β-delayed proton. 20Mg deduced decay scheme.
1979AYZX: 20Mg; measured spectra of β-delayed protons. 20Mg deduced T1/2, mass, coefficients of isobaric multiplet mass equation.
1979MO02: 20Mg; measured β-delayed protons. 20Na deduced mass excess.
1980MOZM: 20Mg; measured β-delayed Ep, Ip. 20Na deduced T = 2, 0+ state mass excess.
1981AY01: 20Mg; measured β-delayed Ep, Ip; deduced T1/2, proton-branching; deduced coefficients of isobaric multiplet mass equation. 20Na level deduced mass excess.
1991KUZP: 20Mg(β+); measured Ep, Eβ, Eγ.
1991KUZR: 20Mg(β+); measured Ep, Eβ, Eγ; deduced rapid proton process mechanism. 20Na deduced levels.
1992GO10: 20Mg(β+p); measured β-delayed Ep, Ip; deduced log ft.
1992KU07: 20Mg(β+); measured T1/2, βp-coin; deduced log ft. 20Na deduced levels, possible J, π.
1992KU24: 20Mg(β+); measured decay curve. 20Na deduced 1+ state may not be s-wave resonance.
1992KUZO: 20Mg(β+); measured Ep, Eα, T1/2 of 20Mg. 20Na deduced levels, J, π.
1992KUZQ: 20Mg(β+), (β+p); measured Ep, pβ-, αβ-coin, T1/2. 20Mg deduced β+ decay branching. 20Na deduced levels, J, π, β+ decay branching.
1992PIZT: 20Mg(β+p); measured β-delayed particle spectra, Eβ, Iβ, γγ-coin; deduced r-process implications. 20Na deduced levels, Fermi, Gamow-Teller transition strengths.
1993PIZZ: 20Mg(β+p); measured β-delayed particle-, γ-spectra; deduced log ft consequences on 19Ne(p, γ) reaction. 20Na deduced levels, J, π, β-branching ratio.
1995PI03: 20Mg(β+p); measured β-delayed Ep, Ip, γ spectra. 20Na levels deduced J, π, β-decay feeding upper limit, Gamow-Teller transition strength.
2012WA15: 20Mg(β+p); measured decay products, Eβ, Iβ, Ep, Ip. 19Ne; deduced proton energy spectrum, resonant states, resonance strengths.
2015GL03: 20Mg(β+); measured Eγ, Iγ, βγ-coin. 20Na; deduced levels, precise energy of the T = 2 state, J, π.
2016LI45: 20Mg(β+p), (β+2p); measured decay products, Ep, Ip; deduced energy, T1/2, branching-ratios.
2016LU13: 20Mg(β+p); measured decay products, Ep, Ip, Eγ, Iγ; deduced T1/2, decay scheme, J, π, absolute beta-delayed proton emission branching ratio, resonance parameters.
2017SU05: 20Mg(β+), (β+p); measured reaction products, Ep, Ip, Eγ, Iγ, γγ-, γβ- and pβ-coin, (20Mg)γ-coin, half-life of 20Mg decay. 20Na, 19Ne; deduced levels, branching ratios, log ft values.
2017WR02: 20Mg(β+), (β+p); measured Eγ, Iγ, βγ- and (implants)γ-coin. 19Ne; deduced level at 4034 keV, β+-delayed proton branching ratio; discussed possible α-decay of 4034 level. 20Mg(β+α); discussed possible decay branch.
2018GL01: 20Mg(β+), measured decay products, Eβ, Iβ, Eγ, Iγ; deduced γ-ray energies and limits on intensities of β-delayed γ-rays, Gamow-Teller strengths B(GT) and associated log ft values.
Measured half-life for 20Mg(β+)20Na

Recommended value (April, 2017): 90.4 ± 0.7 ms
Summary Table of Uncertainty Analysis:   Table 20Mg preview (PDF);   Summary chart of all values:   Table 20Mg preview (PDF)
Measured values: 90.0 ± 0.6 ms (2017SU05)
91.4 ± 1.0 ms (2016LU13)
95 ± 3 ms (1995PI03)
82 ± 4 ms (1992GO10)
114 ± 17 ms (1992KU07)
95+80-50 ms (1979MO02)
  85 ± 15 ms (1964FL03)
Other Reviews: 91 ± 4 ms (Our analysis in August, 2015)

Previous Measurements

 

Decay to 20Na*
(keV) a
Jπ a Branching Ratio (%) log ft B(GT) b
(1992GO10) (1992KU07) (1995PI03) c (1992GO10) (1992KU07) (1995PI03) (1995PI03)
984.25 ± 0.10 1+ 74 ± 7   85 69.7 ± 1.2   3.70 ± 0.05 3.87 3.83 ± 0.02 0.579 ± 0.030
2645 ? ≤ 0.2 < 1  ≤ 0.1 ≥ 5.85 > 5.42     ≥ 6.24 ≤ 0.002
3001 ± 2   1+ 10.7 ± 0.5     9 11.5 ± 1.4   3.99 ± 0.04 4.31 4.08 ± 0.06 0.33 ± 0.05
3874 ± 15 1+ 5.4 ± 0.5   5 4.8 ± 0.6 3.99 ± 0.05 4.26 4.17 ± 0.06 0.27 ± 0.04
4123 ± 16 1+     2.7 ± 0.3     4.33 ± 0.06 0.18 ± 0.03
≈ 4800 d 1+     ≥ 1.9
[3.6 ± 0.5]
    ≤ 4.23
[3.95 ± 0.06]
≥ 0.23
[0.45 ± 0.07]
≈ 5600 d 1+     ≥ 1.5
[2.8 ± 0.4]
    ≤ 3.97
[3.70 ± 0.06]
≥ 0.42
[0.79 ± 0.10]
6266 ± 30 1+     1.2 ± 0.1     3.72 ± 0.06 0.75 ± 0.11
6521 ± 30 0+   3.0 ± 0.8 e 1.5 3.3 ± 0.4   3.08 ± 0.22 e 3.68 3.13 ± 0.06 B(F)
4.57 ± 0.68
  6770 ± 100 (1+)     ≥ 0.03     ≤ 5.01 ≥ 0.04
  6920 ± 100 (1+)     ≥ 0.01     ≤ 5.39 ≥ 0.03
  7440 ± 100 (1+)     ≥ 0.01     ≤ 4.99 ≥ 0.04
a) From (1995PI03).
b) Gamow-Teller strength.
c) These branching ratios refer to the number of implanted 20Mg atoms as 100%. For details on branching of the proton decay into 19Ne levels see (1995PI03).
d) Unresolved levels. These are broad or unresolved states, for which the branching percentage could be determined only from proton emission to excited 19Ne levels. The numbers in square brackets indicate the estimated branch, log ft and B(GT) values under inclusion of the 3% branching to the 19Ne ground state.
e) Branching ratio for this super-allowed decay = (3 ± 2)%, and log ft = 3.18 in (1979MO02).

20C(β-)20N Evaluated Data

20N(β-)20O Evaluated Data

20O(β-)20F Evaluated Data

20F(β-)20Ne Evaluated Data

20Na(β+)20Ne Evaluated Data

A = 20 Beta-Decays Diagram

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Last modified: 21 May 2018