(See Energy Level Diagrams for 8B)
GENERAL: See also (1966LA04) and Table 8.11 [Table of Energy Levels] (in PDF or PS).
Shell model: (1966BA26, 1973HA49).
Special levels: (1966BA26).
Electromagnetic transitions: (1966BA26, 1973HA49).
Special reactions: (1968BA1M, 1968BH1A, 1969BA1L, 1970BA44, 1972AG01).
Astrophysical questions: (1967BA1J, 1967SH1F, 1968BA2E, 1968BA2F, 1969FO1D, 1970BA1M, 1972PA1C).
Other topics: (1966KE16, 1966TO04, 1967DI1B, 1969GA1G, 1972AN05, 1973RO1R).
Ground-state properties: (1966BA26, 1972VA36, 1973HA77, 1973MA1K, 1973SU1B).
The β+ decay leads mainly to 8Be*(2.9). The half-life is 774 ± 5 msec (1964MA35), 762 ± 5 msec (1971WI05), 772 ± 4 msec (1973MCZW): the mean is 770 ± 3 msec. See also Table 8.19 (in PDF or PS) in (1966LA04): log ft = 5.64 ((1966BA1A) and B. Zimmerman, private communication). There is also a branch to a 8Be state at ≈ 16.6 MeV; log ft = 2.9 (1964MA35). See, however, (1969BA43): log ft = 3.33. Measurements of the excitation spectra in the decays of 8Li and 8B show no evidence for second-class currents: |gIT| < 7 × 10-4 (1971WI05). See also (1964FO1A, 1969BA1X, 1969BA1M, 1972BA2M, 1972KO1A, 1973BA2C) for astrophysical applications, (1967BA1M, 1970DA21, 1971LI1H, 1971WI1C, 1971WI18, 1972EM02, 1972HO23, 1972WI28, 1972WI1C, 1973EM1B, 1973HA49, 1973TO14, 1974WI1L; theor.).
At E(3He) = 3.5 to 5.7 MeV, time-of-flight spectra locate the first excited state at 0.767 ± 0.012 (1965FA03, 1966FA1A), 0.783 ± 0.010 MeV (1965MC06: Γ = 40 ± 10 keV). Angular distributions for the n0 group have been reported at E(3He) = 4.8 to 5.7 MeV. The appearance of a forward peak indicates an L = 0 transfer and hence a knockout mechanism (L = 0 is forbidden for simple diproton stripping) (1967VA24). See also (1963DI02). A state at Ex = 2.17 ± 0.05 MeV is reported by (1963DI02; abstract). For threshold measurements see (1966LA04). See also 9B.
Absolute cross sections have been measured for Ep = 0.165 to 10.0 MeV (1969KA1K, 1972KA1B), 0.48 to 1.93 MeV (1966PA16) and 0.95 to 3.28 MeV (1970VA26). In the data of (1966PA16, 1972KA1B) a resonance at Ep = 724 keV reflects 8B*(0.77) with Γlab ≈ 46 keV: the peak cross section is 2.20 ± 0.22 μb, Γγ = 50 ± 25 meV. See also (1969KA1K).
The low-energy cross-section factor, evaluated at the Gamow peak (Ep ≈ 20 keV), S(0.02) = 0.031 keV · b (1973RO08). Other values are S(0) = 0.0335 ± 0.003 keV · b, dS/dE = -3 × 10-5 b (1972KA1B), 0.035 ± 0.004 keV · b, dS/dE = -3 × 10-5 b (1968PA1M) and 0.0430 ≤ S(0) ≤ 0.0453 keV · b (1970AU1B). See also (1969KA1K, 1970VA26). The relevance of this reaction to astrophysics is discussed by (1965TO02, 1966PA16, 1967FO1B, 1967TO1B, 1968BA1W, 1968BA2E, 1968PA1M, 1969BA1U, 1969BA1M, 1970AU1B, 1970VA26, 1971BA2X, 1972BA2M, 1972KA1B, 1972PA1C, 1972TO1D, 1973BA2C, 1973RO08, 1973TR1E).
At Ep = 49.5 MeV angular distributions have been measured for the tritons to 8B*(0, 2.32) (1970SQ01): L = 2 and L = 0 + 2, leading to Jπ = 2+ and 3+, respectively. See also 10B(p, 3He)8Be. The energy of the excited state is 2.29 ± 0.05 MeV (1970SQ01), 2.34 ± 0.04 MeV (1968BR23): Γlab = 390 ± 40 keV (1967MC14). 8B*(0.78) is also observed. See also (1971KA04; theor.).
At E(3He) = 50 MeV, 6He groups are observed to the first three states of 8B (1967MC14).
This reaction has been studied at E(3He) = 40.7 MeV (1971DE37).