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GENERAL: See also (80AJ01) and Table 12.1 [Table of Energy Levels] (in PDF or PS).

Theoretical papers:(KO79LL, AV81B, SE81C, NG82, AN83D, MI83G, VA84).

Hypernuclei:(GA80P, IK82, KA82T, PO82A, BR83R, DO83I, MI83G, DO84).

Other topics:(OL83, WI83H, HI84).

Mass of ¹²Be: The Q-value of the ¹⁰Be(t, p) reaction (-4809 ± 15 keV) (AL78E) 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 (AL78C): log ft = 3.84 ± 0.06 (M.J. Martin, private communication), assuming the decay is to ¹²B_g.s.. The upper limit to a branch involving delayed neutrons is 1% (AL78C).

2. 10Be(t, p)12Be

Qm = -4.809

At E_t = 12 MeV ¹²Be*(2.10) is populated [E_x = 2115 ± 15 keV] and (p, γ) angular correlations lead to J = 2 (AL78C). At E_t = 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 E_x = 12.27 ± 0.04 MeV (AL78E): compare with ¹²O. See also (80AJ01).

3. 12C(π-, π+)12Be

Qm = -25.077

See (NA80D, NA80J). See also (80AJ01).

4. 14C(14C, 16O)12Be

Qm = -14.300

At E(¹⁴C) = 60 MeV ¹²Be*(0, 2.10, 2.68 ± 0.03) have been populated, the latter weakly. Angular distributions are poorly fitted by DWBA. An assignment of 0⁺ is plausible but not proven for ¹²Be*(2.69) (BE82J).