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USNDP

14B (1981AJ01)


(See Energy Level Diagrams for 14B)

GENERAL: See also (1976AJ04) and Table 14.1 [Table of Energy Levels] (in PDF or PS).

See (1975FE1A, 1977AR06, 1979KI11).

Mass of 14B: The atomic mass excess of 14B is 23.644 ± 0.027 MeV, based on the mean of the values reported by (1973BA34) and (1980NA14).

T = 2 states of A = 14: On the basis of the mass of 14B, the lowest T = 2 states in 14C, 14N and 14O are estimated to lie at Ex = 22.5, 24.8 and 22.5 MeV (1973BA34).

1. 14B(β-)14C Qm = 20.62

14B has a half-life of 16.1 ± 1.2 msec. The β-decay is primarily to 14C*(6.09) [Jπ = 1-] and (6.73) [Jπ = 3-]: see Table 14.2 (in PDF or PS). The measured γ-ray intensity ratios are I6.09/I6.73/I7.34 = 100/(10.0 ± 2.0)/< 2.2. The nature of the decay fixes the Jπ of 14B to be 2- (1974AL11).

2. 10Be(6Li, 2p)14B Qm = -11.53

14B has been populated in this reaction at E(6Li) = 31 MeV (1974AL11).

3. 14C(7Li, 7Be)14B Qm = -21.49

14B states with 0 < Ex < 3 MeV have been populated in this reaction at E(7Li) = 52 MeV: see Table 14.1 (in PDF or PS). Similarities in the relative intensities of 14B*(0, 0.74, 1.38, 1.82, 2.08) and of 12B*(1.67, 2.62, 3.39, 4.37, 4.52) [populated in 12C(7Li, 7Be)12B], and the similarity in the ΔEx of these 12B states with the Ex of the 14B states suggest that they have the same Jπ (1973BA34).

4. 14C(14C, 14N)14B Qm = -20.47

At E(14C) = 87.4 MeV, the ground state of 14B is observed: the atomic mass excess is 23.59 ± 0.06 MeV. The first excited state is not populated (1980NA14).