| Recommended value (September, 2015): | 20.22 ± 0.04 ms: | Weighted average with external uncertainty |
| Summary Table of Uncertainty Analysis: |  (PDF) |
|
| Measured values: | 20.18 ± 0.72 ms | (2003ZH32) |
| 20.20 ± 0.02 ms | (1978AL01) | |
| 20.3 ± 0.1 ms | (1963FI05) | |
| 20.2 ± 0.2 ms | (1963PE10) | |
| 20.80 ± 0.15 ms | (1962NE14) | |
| 20.15 ± 0.2 ms | (1962PO02) | |
| 20.31 ± 0.20 ms | (1961SC09) | |
| 20.4 ± 0.4 ms | (1959FA03) | |
| 18.87 ± 0.50 ms | (1959KR1B) | |
| 20.7 ± 0.3 ms | (1958BU1E) | |
| 20.6 ± 0.2 ms | (1958KR65) | |
| 18+1.5-1.3 | (1957CO57) | |
| 22 ± 1 ms | (1953BR1B) | |
| 27 ± 2 ms | (1948JE03) | |
| 22 ± 2 ms | (1939BE1A) |
| Decay to 12C* (MeV ± keV) c |
Jπ | Branching Ratio (%) | Log ft | ||
|---|---|---|---|---|---|
| 0 b | 0+ | (1958CO66) | 97 | (1958CO66) | 4.1 ± 0.1 a |
| (1974MC11) | 97.13 ± 0.31 | (1974MC11) | 4.072 ± 0.002 | ||
| (1978AL01) | 97.14 ± 0.30 | (1978AL01) | 4.067 ± 0.002 f | ||
| (1968AJ02) | 97.1 | 4.075 ± 0.002 g | |||
| (1990AJ01) | 97.22 ± 0.30 | 4.066 ± 0.002 k | |||
| Adopted | 98.300 ± 0.028 h | Adopted | 4.0618 ± 0.0009 i | ||
| 4.43982 ± 0.21 | 2+ | (1956TA07) | 1.7 ± 0.4 | (1958CO66) | 5.1 ± 0.2 a |
| (1958KA31) | 1.4 ± 0.4 | ||||
| (1963PE10) | 1.3 ± 0.1 | 5.10 ± 0.03 g | |||
| (1972AL31) | 1.27 ± 0.06 | (1974MC11) | 5.11 ± 0.02 | ||
| (1978AL01) | 1.276 ± 0.05 | (1990AJ01) | 5.108 ± 0.014 k | ||
| Adopted / (1981KA31) | 1.182 ± 0.019 | Adopted / (1981KA31) | 5.143 ± 0.007 i | ||
| 7.65407 ± 0.19 d | 0+ | (1957CO59, 1958CO66) | 1.3 ± 0.4 | (1958CO66) | 4.2 ± 0.3 a |
| (1963AL15) | 1.1 ± 0.3 j | 4.14 ± 0.10 g | |||
| (2009HY01) | 0.54 ± 0.02 m, n | (1990AJ01) | 4.13 ± 0.09 k | (2016MU06) | 0.63 ± 0.11 o |
| Adopted | 0.54 ± 0.02 | Adopted | 4.574 ± 0.017 i | ||
| 10.3 ± 300 e | (0+) l | (1958CO66) | 0.13 ± 0.04 p | (1958CO66) | 4.1 ± 0.4 a |
| (1963WI05) | 0.07 ± 0.02 p | 4.2 ± 0.2 g | |||
| Adopted | 0.062 ± 0.003 | Adopted | 4.29 ± 0.20 i | ||
| [9 - 12 MeV] r | (2009HY01) | 0.063 ± 0.003 m, n | |||
| 0.055 ± 0.007 q, n | |||||
| 12.7 | 1+ | (2009HY01) | (2.6 ± 0.2) × 10-4 m, n | ||
| (3.2 ± 0.7) × 10-4 q, n | |||||
| Adopted | (2.6 ± 0.2) × 10-4 | Adopted | 3.91 ± 0.04 i | ||
| a) Based on T1/2 = 20.6 ms. |
| b) Eβ- = 13.381 ± 0.041 MeV (1962MA22). |
| c) See (2017KE05). |
| d) See (1976NO02). |
| e) Γ = 3.0 ± 0.7 MeV, θ2α = 1.5 (1966SC23). |
| f) Based on Qm and T1/2 = 20.20 ms (1985AJ01). |
| g) Based on Qm and T1/2 = 20.41 ms: see (1966BA1A). |
| h) 100% minus the branching ratios measured to excited states. |
| i) Based on Qm = 13369.4 ± 1.3 keV and T1/2 = 20.20 ± 0.02 ms. |
| j) In the original manuscript, the value (1.7 ± 0.5)% is calculated using Γγ/Γ = (2.9 ± 0.3) × 10-4 and B(4.4) = (1.3 ± 0.1)%. Here we used Γγ/Γ = 4.16 and B(4.4) = (1.182 ± 0.019)%. |
| k) Based on Qm and T1/2 = 20.20 ± 0.02 ms (M.J. Martin, private communication to Fay Ajzenberg-Selove (1990AJ01). |
| l) (1958CO66) suggest J = 0+. |
| m) Analysis of KVI data in (2009HY01). |
| n) In (2009HY01) the branching ratios are normalized to B(4.44) = (1.28 ± 0.04)% from (1990AJ01). In the present evaluation we adopted (1.182 ± 0.019)%. In the table the (2009HY01) values have been renormalized (decreased) to the updated B(4.44). |
| o) In the original manuscript, the value (0.64 ± 0.11)% is calculated using Γγ/Γ = (4.07 ± 0.11) × 10-4. Here we used Γγ/Γ = (4.16 ± 0.11) × 10-4. |
|
p) The analysis neglected β feeding to |
| q) Analysis of JYFL data in (2009HY01). |
| r) (2009HY01) integrated the strength in the Ex = 9 - 12 MeV region rather than attributing the strength to a 10.3 MeV group, see discussion. |
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Last modified: 29 June 2021