| Recommended value (July, 2015): | 193 ± 6 ms | |
| Summary Table of Uncertainty Analysis: |  (PDF) |
|
| Measured values: | 193 ± 6 ms | (1995SC03) |
| 191 ± 12 ms | (1994RE1R: see also 174 ± 31 ms in (1991RE02) and 188 ± 10 ms in | |
| the unpublished private communications of (2008REZZ)/(1995REZZ).) | ||
| 180 ± 31 ms | (1988SA04) | |
| 202 ± 17 ms | (1986CU01) | |
| 220 ± 80 ms | (1986DU07) | |
| Other Reviews: | 191 ± 6 ms | (2015BI05) |
| Decay to 17N* (keV) |
Jπ | Branching Ratio (%) | Transition to 17N* (keV) |
Eγ (keV) | Branching Ratio (%) | τm (ps) | |
|---|---|---|---|---|---|---|---|
| (1989WA06) a | (1986DU07) | (1986DU07) b | (1982AJ01) c | (1982AJ01) c | |||
| 1374 | 3/2- | 21 ± 10 | 0 | 1374.7 ± 0.5 | 100 ± 20 | 100 | 95 ± 35 fs |
| 1850 | 1/2+ | 40 ± 7 | 1374 | 475.6 ± 0.4 | 22 ± 7 | 13.5 ± 2.5 | 41+20-9 |
| 0 | 1848.7 ± 0.6 | 75 ± 13 | 86.5 ± 2.5 | ||||
| 1907 | 5/2- | 20 ± 8 | 1374 | 23.0 ± 2.5 | 11 ± 2 | ||
| 0 | 1906.0 ± 0.6 | 49 ± 13 | 77.0 ± 2.5 | ||||
| 2526 | 5/2+ | 19 ± 9 | 1907 | 619.6 ± 0.5 | 18 ± 8 | 41.0 ± 2.5 | 33 ± 4 |
| 1850 | 12.0 ± 1.5 | ||||||
| 1374 | 34 ± 23 | ||||||
| 0 | 11 ± 1 | ||||||
| β-delayed neutron decay of 17C | |||||||
| (1995SC03) | |||||||
| Enlab (keV) | Ex(17N) (keV) d | Branching Ratio (%) | log ft d | ||||
| 1620 ± 20 | 7600 ± 20 | 4.6 ± 0.5 | 4.58 ± 0.05 e | ||||
| 1930 ± 20 | 7940 ± 20 | 2.5 ± 0.3 | 4.71 ± 0.06 e | ||||
| 2820 ± 30 f | 8880 ± 20 | 2.6 ± 0.3 | 4.31 ± 0.05 | ||||
| 3730 ± 40 g | 9850 ± 20 | 1.1 ± 0.2 | 4.18 ± 0.06 | ||||
| Total Branching Ratio (%) h, i | 10.8 ± 2.2 | ||||||
| a) These intensities are relative ones for decay to bound states. To obtain absolute intensities, one would scale by a factor (1 - Pn) where the fraction of decays leading to neutron-unstable states Pn = 0.320 ± 0.027 (1991RE02). This yields 14 ± 7, 27 ± 5, 14 ± 6 and 13 ± 6 for 17N*(1374, 1850, 1907, 2526) respectively. |
| b) Relative intensities. |
| c) From (1974RO27, 1974RO28, 1976GU14). |
| d) Assuming neutron decay to the ground state of 16N; for neutron transitions to excited states in 16N, the log ft values represent an upper limit. |
| e) The energy separation of the first two neutron groups corresponds to the excitation energy of the second excited state in 16N. For this reason it cannot be excluded that these two groups correspond to the neutron decay of one 17N state to the ground state and second excited state of 16N. In this case the combined branching ratio would correspond to a log ft value of 4.26. |
| f) Γ = 425 + 150 keV. An unresolved doublet with En = 2.65 and 2.91 MeV cannot be excluded. Under this assumption the neutron group could correspond to a state at Ex = 8.70 MeV which neutron decays to the ground state and the second excited state of 16N. |
| g) Γ = 435 + 70 keV. An unresolved doublet with En = 3.35 and 3.86 MeV cannot be excluded. Under this assumption the neutron group could correspond to a state at Ex = 9.44 MeV which neutron decays to the ground state and the third excited state of 16N. |
| h) The errors of the total efficiency (10%), the background subtraction (15%), and the number of observed β-decays (10%) have been added after summing. |
| i) (1991RE02) measured the β-delayed neutron probability, Pn = 32.0 ± 2.7 % with a polyethylene-moderated 3He neutron counter with a nominaly zero energy threshold. The apparent discrepency between (1991RE02) and (1995SC03) is best understood as evidence for β-feeding of lower energy states that neutron decay with energies below the threshold of (1995SC03). |
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Last modified: 29 June 2021