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## 12Be (1985AJ01)

(See Energy Level Diagrams for 12Be)

GENERAL: See also (1980AJ01) and Table 12.1 [Table of Energy Levels] (in PDF or PS).

Theoretical papers:(1979KO29, 1981AV02, 1981SE06, 1982NG01, 1983ANZQ, 1983MI1E, 1984VA06).

Hypernuclei:(1980GA1P, 1982IK1A, 1982KA1D, 1982PO1C, 1983BR1E, 1983DO1B, 1983MI1E, 1984DO04).

Other topics:(1983OL1A, 1983WI1A, 1984HI1A).

Mass of 12Be: The Q-value of the 10Be(t, p) reaction (-4809 ± 15 keV) (1978AL29) leads to an atomic mass excess of 25077 ± 15 keV for 12Be.

 1. 12Be(β-)12B Qm = 11.708

The half-life of 12Be is 24.4 ± 3.0 msec (1978AL10): log ft = 3.84 ± 0.06 (M.J. Martin, private communication), assuming the decay is to 12Bg.s.. The upper limit to a branch involving delayed neutrons is 1% (1978AL10).

 2. 10Be(t, p)12Be Qm = -4.809

At Et = 12 MeV 12Be*(2.10) is populated [Ex = 2110 ± 15 keV] and (p, γ) angular correlations lead to J = 2 (1978AL10). At Et = 17 MeV proton groups are observed to the states shown in Table 12.1 (in PDF or PS). The energy of 12Be*(2.10) is measured to be 2089 ± 20 keV. The two highest states have an appreciable intrinsic width. From the measured atomic mass excess of 12Be, d, the cubic factor in the IMME, is calculated to be +2.8 ± 8.6 keV and the first T = 2 state in 12N should occur at Ex = 12.27 ± 0.04 MeV (1978AL29): compare with 12O. See also (1980AJ01).

 3. 12C(π-, π+)12Be Qm = -25.077