12N

β+-Decay Evaluated Data



Measurements
1949AL05: 12N; measured T1/2.
1958VE20: 12N; measured T1/2.
1959FA03: 12N; measured T1/2.
1962MA22: 12N; measured not abstracted; deduced nuclear properties.
1962PO02: 12N; measured not abstracted; deduced nuclear properties.
1963FI05: 12N; measured not abstracted; deduced nuclear properties.
1963GL04: 12N; measured not abstracted; deduced nuclear properties.
1963PE10: 12N; measured not abstracted; deduced nuclear properties.
1963WI05: 12N; measured not abstracted; deduced nuclear properties.
1967AL03: 12N; measured not abstracted; deduced nuclear properties.
1972AL31: 12N; measured βγ-coin; deduced log ft, β-branching.
1974MC11: 12N; measured Eβ, Iβ, βγ-coin; deduced log ft.
1978AL01: 12N; measured Eβ, Iβ, βγ-coin, T1/2; deduced β-branching, mirror asymmetries, ft.
1978BR18: 12N; measured alignment-positron-momentum correlation using spontaneous level mixing technique; deduced evidence against second-class axial current.
1978SU1J, 1979MA31:12N; measured βγ-(θ), Iβ(θ). 12N deduced alignment-correlation coefficients deduced information vector currents. NMR, aligned sources.
1981KA31: 12N; measured βγ-coin, βγ(t); deduced Iβ, log ft.
1985FUZT: 12N(β+); measured β-asymmetry, NMR; deduced quadrupole coupling constant.
1985IM02: 12N(β+); measured Eβ, Iβ.
1985IWZZ: 12N(β+); measured β-asymmetry; deduced nuclear polarization.
1987KU17: 12N(β+); measured NMR spectra in GaN; deduced quadrupole effects.
1987MI20: 12N(β+); measured Iβ(θ), aligned nuclei; deduced weak nucleon current parity conservation in isospin space.
1987MI24: 12N(β+); measured NMR spectra in V crystal; deduced nuclear dipolar broadening.
1988NA09: 12N; deduced Gamow-Teller β-decay branching ratio.
1988SHZO: 12N(β+); measured Eβ; deduced shape factor.
1990CA10: 12N(β+); measured spectral shape factors.
1991LI32: 12N; measured β-decay asymmetry.
1992BA11: 12; calculated Gamow-Teller β-decay ft-value asymmetry. R-matrix approach.
1992SHZI: 12N(β+); measured Eβ.
1992SOZS: 12N(β+); measured β(E, θ); deduced polarization correlation coefficient.
1992TAZP: 12N(β+); measured T1/2.
1993MAZU: 12N(β+); measured β(E, θ) from spin polarized 12N implanted in Al; deduced polarization correlation coefficient.
1993OHZX: 12N(β+); measured NMR. 12N deduced quadrupole moment.
1994OHZY: 12N(β+); measured β-NMR; deduced quadrupole moment.
1996AL23: 12N(β+); measured β+ polarization, polarized source
1997MIZS: 12N(β+); measured alignment correlation terms in β-ray angular distribution from aligned 12N; deduced validity of G-parity conservation law.
1997YAZW: 12N(β+); measured alignment correlation terms in β-ray angular distribution from aligned 12N.
1998MA27: 12N(β+); measured β-NMR.
1998MI10: 12N(β+); measured β-NMR. 12N deduced quadrupole moment.
1998MI14: 12N(β+); measured β-ray angular distribution from oriented nuclei; deduced nonzero G-parity violating induced tensor form factor.
1998MI20: 12N(β+); measured β-NMR. 12N deduced quadrupole moment.
1998MIZU: 12N(β+); measured Iβ(θ) from spin aligned nuclei.
1998OHZZ: 12N(β+); measured Eβ; deduced spectral shape factor.
1998SE04: 12N(β+); measured β+ polarization asymmetry from decay of polarized nuclei.
2000MI11: 12N(β+); measured β angular distributions from aligned nuclei.
2000MIZQ: 12N(EC); measured β-NMR; deduced G-parity irregularity.
2001TH18: 12N(β+); measured positrons longitudinal polarization following decay of polarized source.
2002FY02, 2003FY02: 12N(EC); measured β-delayed α-spectra, αα-coin.
2002MI01: 12N(β+); measured Eβ, angular distributions from spin-aligned sources.
2002MI03, 2002MIZZ: 12N(β+); measured Eβ, angular distributions from spin-aligned sources; deduced tensor form factor.
2002MI36: 12N(EC); measured Eβ, Iβ(θ, H, t) from oriented nuclei.
2002MI49: 12N(EC); measured Eβ, Iβ(θ, H, t) from polarized sources; deduced in-medium nucleon mass renormalization, induced tensor form factor.
2003FY04, 2004FY02: 12N(EC); measured β-delayed Eα, αα-coin. 12C deduced excited states.
2003MI24: 12N(β+); measured Eβ, angular distributions from spin-aligned sources; deduced G-parity irregular induced tensor coefficient.
2004BO43: 12N(β+); measured β-delayed particle spectra, yields. 12C deduced excited states particle-decay features.
2004FY03: 12N(β+); measured β-delayed Eα, αα-coin. 12C deduced levels, J, π, resonance features.
2007PEZY: 12N(β+); measured branching β-decay ratios.
2009DI06: 12N(β+); measured Eα, Eγ, ααα-coin. 12C; deduced levels, J, π, triple-α continuum states and their decay modes.
2009HY01: 12N(β+); deduced branching ratio, log ft, B(GT) to various 12C states.
2009HY02: 12N(β+); measured Eα, Iα, Eγ, Iγ, Eβ, βγ-, βα-, ααα-coin. 12C; deduced levels, β feedings, and log ft. Triple-α method and R-matrix analysis.
2010HY01: 12N(β+); measured 3α summed spectra and associated branching ratios for breakup via the 8Be ground-state and via excited states of 8Be. 12C; deduced levels, resonances, Gammow-Teller strengths and widths using multilevel, many-channel R-matrix formalism.
2014TE01: 12N(EC); measured decay products, Eβ, Iβ; deduced breakup of excited states in 12C.
Measured half-life for 12N(β+)12C

Recommended value (August, 2015): 11.000 ± 0.016 ms
Summary Table of Uncertainty Analysis:  Table 12N preview (PDF)  
Measured values: 11.000 ± 0.016 ms (1978AL01)
10.95 ± 0.05 ms (1963FI05)
11.0 ± 0.1 ms (1963PE10)
11.1 ± 0.2 ms (1962PO02)
11.2 ± 0.4 ms (1959FA03)
11.43 ± 0.05 ms (1958VE20) (Excluded)
12.5 ± 1.0 ms (1949AL05)

Previous Measurements

 

Decay to 12C*
(MeV)
References Eβ (MeV) Branching Ratio (%) Log ft
0 (1949AL05) 16.6 ± 0.2     4.18 a
(1958VE20) 16.37 ± 0.06 100 4.17
(1963GL04, 1963PE10) 16.384 ± 0.015 94.25 4.117 ± 0.002 b
4.119 ± 0.003 c
(1978AL01)   94.55 ± 0.60 4.120 ± 0.003 d
Adopted     96.15 ± 0.05 l 4.1107 ± 0.0007 g
4.43982 ± 0.21    (1958VE20)   15 4.4  
(1963PE10)     2.4 ± 0.2  
(1963WI05)         2.2 ± 0.25 e  
(1972AL31, 1974MC11) f     2.10 ± 0.16 5.11 ± 0.03 c
(1978AL01)     2.00 ± 0.10 5.128 ± 0.023 d
Adopted / (1981KA31)     1.898 ± 0.032 5.148 ± 0.008 g
7.65407 ± 0.19 h (1962MA22)     3.0 ± 0.5  
(1963GL04)     2.2 ± 0.6  
(2009HY01)         1.41 ± 0.03 m  
Adopted     1.41 ± 0.03 4.622 ± 0.010 g
    10.3 ± 300 i (1963GL04)     0.85 ± 0.6 s  
(1963WI05)       0.44 ± 0.15 s  
Adopted     0.404 ± 0.009 4.42 ± 0.11 g
[9 -12 MeV] j (2009HY01)        0.404 ± 0.009 m  
      0.38 ± 0.05 n  
12.7 (1966SC23)     ≈ 2.0 o  
(1967AL03)       0.29 ± 0.08 k 3.52 ± 0.14 p
(2009HY01)        0.120 ± 0.003 m  
      0.11 ± 0.02 n  
Adopted     0.120 ± 0.003 3.924 ± 0.012 g
[12 -16.3 MeV] j (2009HY01)        0.021 ± 0.006 n  
        0.020 ± 0.003 m  
15.110 ± 3       (1967AL03)   (3.8 ± 0.8) × 10-3 q 3.30 ± 0.13 b
(2009HY01) j   (0.8 ± 0.3) × 10-3 r 3.30 ± 0.13 b
Adopted   (2.3 ± 1.5) × 10-3   3.6 ± 0.3 g
a) (1951FE1A); see also (1952KI1A).
b) Based on Qm and T1/2 = 10.97 ± 0.04 ms: see (1966BA1A).
c) Based on Qm and T1/2 = 10.97 ± 0.04 ms: see (1974MC11 and 1966BA1A).
d) Based on Qm and T1/2 = 11.000 ± 0.016 ms (1980AJ01). See also (1976CA29 and 1978RA2A).
e) 1.72 times 12B value.
f) Based on adopted branching ratio 1.29 ± 0.05 % for 11B(β-) → 12C*(4.4) and "best" value of the 12N/12B ratio for this decay, R = 1.63 ± 0.11.
g) Based on Qm = 17338.1 ± 1.0 keV and T1/2 = 11.000 ± 0.016 ms.
h) See (1976NO02).
i) Γ = 3.0 ± 0.7 MeV, θ2α = 1.5 (1966SC23).
j) (2009HY01) integrated the strength in the Ex = 9 - 12 MeV and 12-16.3 MeV region [excluding the 12.7 MeV state] rather than attributing the strength to a 10.3 MeV group, see discussion.
k) In the original manuscript, the value 0.29 ± 0.13 is calculated using Γγ/Γ(12.7) = (3 ± 1) × 10-2, 0.80 ± 0.07 as the ground state branching fraction and assuming B(4.4) = (2.4 ± 0.2)%. The observable is Iγ(12.7)/Iγ(4.4) = 2.9 × 10-3 (± 26%). We used the values in Table 12.14 in (2017KE05) and B(4.4) = 1.89%.
l) 100% minus the branching ratios measured to excited states.
m) Analysis of KVI data in (2009HY01).
n) Analysis of JYFL data in (2009HY01): normalized to B(4.44) = (1.90 ± 0.03)%.
o) From Iα(10.3)/Iα(12.7) = 0.2 (1966SC23).
p) Based on T1/2 = 11.000 ± 0.016 ms and Qm (1990AJ01).
q) In the original manuscript, the value (4.4 ± 1.5) × 10-3 is calculated using Γγ/Γ = 1 and 0.965 as the ground state branching fraction, and assuming B(4.4) = (2.4 ± 0.2)%. The observable is Iγ(15.11)/Iγ(4.4) = 1.78 × 10-3 (± 20%). We used the values in Table 12.14 in (2017KE05) and B(4.4) = (1.898 ± 0.032)%.
r) The value is (3.2 ± 1.0) × 10-5 · Γ/Γα.
s) The presence of higher lying states was not taken into account.

12Be(β-)12B Evaluated Data

12B(β-)12C Evaluated Data

A = 12 Beta-Decays Diagram

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Last modified: 21 May 2018