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19Ne (1959AJ76)(See Energy Level Diagram for 19Ne) GENERAL: See also Table 19.9 [Table of Energy Levels] (in PDF or PS). Theory: See (1955EL1B, 1955RE1D, 1955RE1E, 1957RA1C, 1958RE1B).
The positron end point is 2.18 ± 0.03 (1952SC15), 2.23 ± 0.05 (1957AL29), 2.24 ± 0.01 MeV (1958WE25). The half-life is 17.4 ± 0.2 sec (1959HE1E), 17.7 ± 0.1 (1957PE12), 18.3 ± 0.5 (1957AL29), 18.5 ± 0.5 (1952SC15), 19 ± 1 (1954NA29), 19.5 ± 1.0 (1958WE25), 20.3 ± 0.5 sec (1939WH02). The absence of low-energy γ-rays (see 19F) indicates that the transition takes place to the ground state, J = 1/2+, of 19F: log ft = 3.30, log ft for a transition to the 0.11 MeV, J = 1/2-, state of 19F is ≥ 6.0, log ft to the 0.20 MeV, J = 5/2+, state is ≥ 5.5. It follows that the ground state of 19Ne is J = 1/2+ (1954JO21). The Kurie plot is linear from the end point to 0.7 MeV (1957AL29). The electron-neutrino angular correlation has been studied by (1955MA1M, 1957AL29, 1957GO1J, 1958HE1J, 1959HE1E). See also (1954AL29, 1959LA01) and (1958RE1B; theor.).
See (1947TE01).
Yield curves for the ground-state alpha-particle group and for proton groups to the first six states of 18F have been obtained for E(3He) = 2.0 to 5.4 MeV. All curves show pronounced resonance structure; in particular, all groups appear to be resonant at E(3He) ≈ 2.45 MeV, corresponding to 19Ne* ≈ 10.48 MeV. Angular distributions have also been measured at several energies (1958BR86).
Not reported.
The ground-state threshold is Ethresh. = 4240 ± 8 keV (1955KI28), 4235 ± 5 keV (1955MA84). Two additional thresholds are observed, corresponding to excited states of 19Ne at 241 ± 4 and 280 ± 4 keV. No other excited states appear with Ex < 1.5 MeV (1955MA84). The two excited states radiate to the ground state with Eγ = 242 ± 5 and 281 ± 8 keV and with lifetimes of (1.8 ± 0.2) × 10-8 sec and < 5 × 10-9 sec (1957BA09). It appears from these results that the position of the first two excited states in the A = 19 pair is reversed in 19F and 19Ne: the sequence in 19F is 1/2+, 1/2-, 5/2+, in 19Ne it appears from the lifetimes to be 1/2+, 5/2+, 1/2-. See also (1958BI1B).
Not reported.
See 20Ne.
Not reported.
Not reported.
Not reported.
Not reported.
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