18N

β--Decay Evaluated Data



Measurements
1964CH19: 18N; measured not abstracted; deduced nuclear properties.
1982OL01: 18N; measured Eγ, Iγ, T1/2; deduced log ft. 18O deduced levels, β-branches.
1989ZH04: 18N(β-); measured absolute β-decay branching ratios; deduced log ft, Gamow-Teller matrix elements. 18O(α) [from 18N β-decay]; measured total β-delayed α-yield. 18O deduced possible new levels.
1993BU21: 18N(β-); measured β-delayed Eα, Iα.
1991RE02, 1993REZX, 1994RE1R: 18N(β-n); measured T1/2, neutron emission probabilities, β-delayed neutron average energies.
1994SC01: 18N(β-); measured β-delayed neutron spectra, T1/2; deduced log ft. 18O deduced levels, J, π, total branching ratio.
1997CO15, 1997NE01: 18N(β-); measured β-asymmetry; deduced alignment related features.
1998CO37, 1998NE04, 1999NE01: 18N(β-); measured β-NMR, β asymmetry vs H. 18N deduced quadrupole moment, deformation.
1998OG04, 1999OG03, 1999OGZV: 18N(β-); measured Iβ(H, t). 18N deduced ground-state Q, μ.
2003FR32: 18N(β-); measured β-delayed Eα, Eγ; deduced absolute branching ratio.
2005LI60: 18N(β-), (β-n); measured T1/2, β-delayed neutron spectra, Eγ; Iγ; deduced branching ratios, Gamow-Teller strengths. 18O deduced levels, J, π.
2007BU01: 18N(β-); measured β-delayed Eα, βα-coin. 18O deduced level energies, J, π, widths. Astrophysical implications discussed.
2007LO05: 18N(β-); measured β-delayed neutron spectra. 18O; deduced level energies, J, π. Deduced B(GT), compared to shell model calculations.
Measured half-life for 18N(β-)18O

Recommended value (July, 2015): 0.619 ± 0.002 sec (2005LI60)
Summary Table of Uncertainty Analysis:  Table 18N preview (PDF)  
Measured values: 0.620 ± 0.008 sec (2007BU01)
0.625 ± 0.030 sec (2007LO05)
0.635 ± 0.040 sec (2007LO05)
0.609 ± 0.060 sec (2007LO05)
0.619 ± 0.002 sec (2005LI60)
0.63 ± 0.02 sec (1994SC01)
0.658 ± 0.044 sec (1994RE1R: see also 790 ± 210 ms in (1991RE02) and 660 ± 35 ms in the
unpublished private communications of (2008REZZ)/(1995REZZ).) (Excluded)
0.624 ± 0.012 sec (1982OL01)
0.63 ± 0.03 sec (1964CH19)
Other Reviews: 0.619 ± 0.002 sec (2015BI05)

Previous Measurements

 

Decay to 18O*
(keV)
Decay
mode
Jπ Branching Ratio (%) a log ft
(1982OL01) (1989ZH04) (1994SC01) (2005LI60) (1982OL01) (1989ZH04) (1994SC01) (2005LI60)
1982.05 ± 0.09 b γ 2+ 3.9 ± 1.5       6.75 ± 0.30      
3554.13 ± 0.80   γ 4+ < 0.6         > 7.27      
3633.70 ± 0.11   γ 0+ < 0.35       > 7.50      
3920.42 ± 0.14   γ 2+ < 0.43       > 7.35      
4455.52 ± 0.10   γ 1- 54.6 ± 1.1         5.146 ± 0.054      
5097.60 ± 0.60   γ 3- < 0.43       > 7.09      
5530.17 ± 0.32   γ 2- 3.1 ± 0.4       6.15 ± 0.07      
6198.22 ± 0.40   γ 1- 1.4 ± 0.2       6.33 ± 0.08      
6349.76 ± 1.0     γ (2-) 2.2 ± 0.3       6.09 ± 0.08      
6880.45 ± 0.27   γ   0- c 14.8 ± 0.8         5.118 ± 0.070      
7620 α 1-      6.8 ± 0.5       5.21 d    
7771.07 ± 0.50   γ   2- c 5.0 ± 0.5       5.32 ± 0.09      
8040 α 1-      1.8 ± 0.2       5.65 d    
8660 ± 20 n (0 - 2)-       5.04 ± 1.12       4.87 ± 0.10
8890 ± 40 n (0 - 2)-       0.28 ± 0.06       6.08 ± 0.09
  9000 e α (1-)   ≥ 3.6 ± 0.2       d    
  (9090 ± 30) f n (0 - 2)-     0.16 ± 0.03 0.11 ± 0.03     6.27 ± 0.09 6.41 ± 0.12
  9270 ± 20 f n (0 - 2)-     0.39 ± 0.09 0.18 ± 0.03     5.81 ± 0.12 6.11 ± 0.07
  9470 ± 20 f n (0 - 2)-     0.47 ± 0.09 0.24 ± 0.04     5.64 ± 0.09 5.90 ± 0.07
  9690 ± 20 f n (0 - 2)-     0.14 ± 0.03 0.05 ± 0.02     6.07 ± 0.10 6.51 ± 0.17
  9910 ± 20 f n (0 - 2)-     0.17 ± 0.03 0.18 ± 0.02     5.88 ± 0.08 5.86 ± 0.05
10240 ± 30 f n (0 - 2)-     0.16 ± 0.03 0.11 ± 0.03     5.75 ± 0.09 5.96 ± 0.12
10650 ± 30 f n (0 - 2)-     0.43 ± 0.09 0.43 ± 0.06     5.08 ± 0.10 5.12 ± 0.06
10990 ± 30 f n (0 - 2)-     0.13 ± 0.03 0.13 ± 0.02     5.39 ± 0.10 5.54 ± 0.07
11490 ± 30 f n (0 - 2)-     0.19 ± 0.04 0.23 ± 0.03     4.85 ± 0.10 4.91 ± 0.06
12050 ± 50 h n (1)-       0.05 ± 0.03       5.24 ± 0.03
    Total BR for the β-delay neutron decay listed   2.2 ± 0.4 g 7.03 ± 1.46        
a) 12.2 ± 0.6 % of the β-decay branching ratio has been measured to feed α-emitting states (1989ZH04). 14.3 ± 2.0 % has been measured to feed n-decaying states (1991RE02). The branching ratio of γ-decaying states (1982OL01) have been renormalized to take these values into account. See reaction 22 of 18O in (1995TI07). Branchings in this table do not add up to 100% since n-decaying levels below 9.00 MeV were not measured by (1994SC01) and there is a missing 12.1% branching to n-decaying levels not listed.
b) Eγ = 1981.933 ± 0.09 keV is adopted by (1982OL01).
c) See (1982OL01).
d) log ft = 5.17 ± 0.04, 5.61 ± 0.05, and ≤ 5.0 for 18O*(7620, 8040, 9000), respectively: see (1995TI07).
e) Found as a broad bump at 3 MeV in β-delayed alpha spectrum. Could be several unresolved 1- states or a new broad 1- state in 18O (1989ZH04).
f) Ex(18O) = (9070 ± 20, 9280 ± 30, 9470 ± 30, 9610 ± 30, 9890 ± 30, 10140 ± 40, 10630 ± 40, 10900 ± 40, and 11450 ± 50), respectively (2005LI60).
g) The common errors of the total efficiency (10%) and the uncertainty of the shape of the background (15%) have been added after the summing (1994SC01).
h) From (2007LO05).

18C(β-)18N Evaluated Data

18F(β+)18O Evaluated Data

18Ne(β+)18F Evaluated Data

A = 18 Beta-Decays Diagram

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Last modified: 20 September 2018