A=11B (1985AJ01)

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¹¹B (1985AJ01)

(See Energy Level Diagrams for ¹¹B)

GENERAL: See also (1980AJ01) and Table 11.4 [Table of Energy Levels] (in PDF or PS).

Shell and deformed models:(1981BO1Y, 1981RA06, 1982BO01, 1983VA31, 1984VA06).

Cluster model:(1979NI06, 1980FU1G, 1983SH38).

Special states:(1979NI06, 1980RI06, 1981BO1Y, 1981RA06, 1981SE06, 1983GO1R, 1983VA31, 1984GO1M, 1984VA06).

Electromagnetic transitions and giant resonances:(1978KR19, 1979DO17, 1979NI06, 1980FU1G, 1980KO1L, 1980RI06, 1981BO1Y, 1982AW02, 1982GO03, 1984KU07).

Astrophysical questions:(1978OR1A, 1979BJ1A, 1979RA1C, 1980CO1R, 1980DO1C, 1980FR1G, 1980RE1B, 1981AU1D, 1981AU1G, 1981GA1C, 1981GU1D, 1982SC1E, 1983HO15, 1983SI1B).

Applied work:(1980MU1D, 1981KU1C, 1983AM1A, 1983FI1C).

Complex reactions involving ¹¹B:(1978VO10, 1979AL22, 1979BO22, 1979GE1A, 1979SA27, 1979SA26, 1979SC1D, 1979ST1D, 1980GR10, 1980MI01, 1980MO28, 1980RI06, 1980WI1L, 1981BH02, 1981CI03, 1981ME13, 1981MO20, 1981TA16, 1981TA22, 1982BI1C, 1982FU04, 1982JA1C, 1982LU01, 1982LY1A, 1982MO1K, 1982WU1B, 1983CH23, 1983EN04, 1983FU04, 1983HA1C, 1983OL1A, 1983SA06, 1983SC1L, 1983SI1A, 1983SO08, 1983WA1F, 1983WI1A, 1984GO03, 1984GR08, 1984HI1A, 1984VO06).

Muon and neutrino capture and reactions (See also reaction 48.):(1980SC18, 1981MU1E, 1981OL01).

Pion and kaon capture and reactions (See also reactions 21, 32 and 50.):(1979AL1J, 1979AL21, 1979BA16, 1979BU1C, 1979KI1G, 1979PE1D, 1979PI1C, 1979ZI05, 1980DE11, 1980GR1G, 1980LE02, 1980SO05, 1980ZI1B, 1981BE63, 1981FE2A, 1981FR17, 1981GE1B, 1981RO1L, 1981RO1R, 1981TH1B, 1981ZI01, 1982DE1K, 1982ER04, 1983AN1F, 1983BA71, 1983FE07, 1983GE12, 1983GE13, 1983MO1F, 1983RO07, 1983ZE1C).

Hypernuclei:(1978SO1A, 1979BU1C, 1980IW1A, 1981ST1G, 1981WA1J, 1982DO1L, 1982ER1E, 1982GR1P, 1982KA1D, 1982KO11, 1982RA1L, 1983CH1T, 1983DO1B, 1983FE07, 1983SH38).

Other topics:(1979NI06, 1981CA1H, 1981SE06, 1982AW02, 1982BE17, 1982DE1N, 1982NG01, 1983GO1R).

Ground-state properties of ¹¹B (See also reactions 31 and 32.):(1979AL26, 1979NI06, 1979SA27, 1980BA45, 1980FU1G, 1980HO14, 1981AV02, 1981BO1Y, 1981OL01, 1981SE06, 1982BA37, 1982BO01, 1982LO13, 1982NG01, 1983ANZQ, 1983BU07, 1983MI08, 1983VA31, 1984KU07, 1984MIZM).

μ = +2.688637(2) nm (1978LEZA),

Q = 40.65(26) mb [see (1980AJ01)],

B(E2; 3/2^- → 1/2^-) = 2.1 ± 0.4 e² · fm⁴ (1980FE07).

1. ⁶Li(⁶Li, p)¹¹B Q_m = 12.215

Angular distributions have been measured for proton groups to states with E_x < 9.3 MeV at E(⁶Li) = 2.4 to 9.0 MeV: see (1980AJ01).

2. ⁷Li(α, γ)¹¹B Q_m = 8.665

Resonances for capture radiation are displayed in Table 11.6 (in PDF or PS).

3. ⁷Li(α, n)¹⁰B Q_m = -2.7898 E_b = 8.665

Table 11.7 (in PDF or PS) displays the thresholds and resonances observed in this reaction. (1981SE04) have measured thick-target yields (± 6%) for E_α = 4.385 to 5.1 MeV at a number of angles: a broad resonance is observed near E_α = 4.7 MeV. Thick-target yields have also been reported from threshold to 9.00 MeV (1979BA48).

4. ⁷Li(α, t)⁸Be Q_m = -2.5599 E_b = 8.665

Excitation functions have been measured for E_α = 14 to 25 MeV (t₀) and 18 to 25 MeV(t₁): see (1980AJ01). See also ⁸Be in (1984AJ01).

5. ⁷Li(α, α)⁷Li E_b = 8.665

The elastic scattering and the scattering to ⁷Li*(0.48) have been studied at many energies to E_α = 22.5 MeV. Recent measurements are reported by (1979ST25; α₀; E_α = 1.36 - 3.20 MeV) and (1981WA1P; α₀; E_α = 5.0 and 6.0 MeV). Observed resonances are displayed in Table 11.8 (in PDF or PS) here. Additional parameters are shown in Table 11.9 (in PDF or PS) of (1975AJ02). See also (1982WA23) and (1980BA2K; theor.).

6. ⁷Li(⁶Li, d)¹¹B Q_m = 7.189

Angular distributions have been measured for E(⁷Li) = 3.3 to 5.95 MeV: see (1975AJ02). See also ¹³C in (1981AJ01).

7. ⁷Li(⁷Li, t)¹¹B Q_m = 6.196

Angular distributions have been measured at E(⁷Li) = 2.10 to 5.75 MeV. At E(⁷Li) = 79.6 MeV transitions are observed to several ¹¹B states. ¹¹B_g.s. is particularly strongly populated. See (1975AJ02) for references.

8. ⁹Be(d, γ)¹¹B Q_m = 15.816

The 90° γ₀ differential cross section has been measured for E_d = 0.5 to 11.9 MeV: see (1975AJ02). The behavior of the γ₀, γ₁ and γ₂₊₃ total cross sections and of the angular distributions of these γ-rays indicate two resonances at E_d = 1.98 ± 0.05 and 3.12 ± 0.05 MeV with Γ_lab = 225 ± 50 and 320 ± 100 keV, corresponding to ¹¹B*(17.43, 18.37). The higher resonance was not observable in the γ₂ + γ₃ cross section which was not measured beyond E_d = 2.5 MeV. The maximum γ₀ cross section observed is 10.1 ± 3.5 μb at E_d ≈ 0.96 MeV. Resonant behavior is observed in the 90° γ₀ cross section at E_d ≈ 3.4 and 9.65 MeV (¹¹B*(18.6, 23.7)) in addition to a wide structure at 4.7 MeV (¹¹B*(19.7)). The angular distributions of γ₀ from ¹¹B*(18.6, 23.7) are typical of E1 transitions. The (d, γ₀) reaction appears to proceed via excitation of the T = 1/2 component of the giant dipole resonance in ¹¹B.

9. ⁹Be(d, n)¹⁰B Q_m = 4.3620 E_b = 15.816

The cross section follows the Gamow function for E_d = 70 to 110 keV. The fast-neutron and gamma yield rise smoothly to E_d = 1.8 MeV except for a possible "resonance" at E_d ≈ 0.94 MeV. The fast neutron yield then remains approximately constant to 3 MeV: see (1968AJ02) for references. The excitation functions for n₀ → n₄, and n to ¹⁰B*(5.1, 6.57) have been measured for E_d = 14 to 16 MeV: no strong fluctuations are observed: see (1975AJ02). Thick-target yields for γ-rays have been measured at E_d = 48 to 170 keV (1982CE02; also deduced astrophysical S-factors). Thick-target yields are also reported at E_d = 14.8, 18.0 and 23.0 MeV: see (1980AJ01). Polarization measurements have been carried out at E_d = 0.4 to 5.5 MeV [see (1975AJ02, 1980AJ01)] and at E_d-bar = 12.3 MeV (1981BR1E, 1983LIZW; VAP; n₀, n₁, n₂). See also (1979GR2D; applied) and ¹⁰B in (1984AJ01).

10. (a) ⁹Be(d, p)¹⁰Be Q_m = 4.5875 E_b = 15.816
(b) ⁹Be(d, α)⁷Li Q_m = 7.152
(c) ⁹Be(d, t)⁸Be Q_m = 4.5918

Measurements of proton yields have been carried out at E_d up to 6.0 MeV for p₀ and p₁ [see (1975AJ02, 1980AJ01)] and at E_d-bar = 29 to 170 keV (1981CE04; thick target yield; σ(θ) at 150°; deduction of astrophysical S(θ, E)) and at E_d-bar = 1.4 to 2.5 MeV (1980DE45; p₀, p₁). The p₀ and p₁ yields show a resonance at E_d = 750 ± 15 keV [¹¹B*(16.43), Γ ≈ 40 keV] and the p₁ yield resonates at 1.85 MeV [¹¹B*(17.33), Γ_c.m. ≈ 1.0 MeV] and 2.3 MeV [¹¹B*(17.70), sharp]. See also (1975AJ02) and (1980DE45) for other possible structures. Polarization of the protons have been measured at E_d = 1 to 21 MeV [see (1975AJ02, 1980AJ01)] and at E_d-bar = 1.4 to 2.5 MeV (1980DE45; VAP; p₀, p₁) and 2.0 to 2.8 MeV (1984AN1R; p₀, p₁). See also ¹⁰Be in (1984AJ01) and (1984DE1W; theor.).

The yeild of α-particles (reaction (b)) has been measured for E_d = 0.3 to 14.43 MeV [see (1975AJ02, 1980AJ01)], at E_d-bar = 1.4 to 2.4 MeV (1980DE42, 1980DE43, 1980DE44; yields of α₀, α₁ and VAP) and 2.0 to 2.8 MeV (1984AN1R; α₀, α₁). The 0.75 MeV resonance, observed in reaction (a), is weakly populated in the α₀ yield. See also ⁷Li in (1984AJ01).

The cross section for reaction (c) has been measured for E_d = 0.15 to 19 MeV: see (1968AJ02, 1975AJ02, 1980AJ01). Polarization measurements are reported at E_d-bar = 12 and 15 MeV [see (1980AJ01)] and at E_d-bar = 2.0 to 2.8 MeV (1984AN1R; t₀). There is no clear evidence of resonance structure. See also ⁸Be in (1984AJ01).

11. ⁹Be(d, d)⁹Be E_b = 15.816

Excitation functions for elastically scattered deuterons have been measured for E_d = 0.4 to 7.0 MeV and for 12.17 to 14.43 MeV (also d₁, d₂) [see (1975AJ02, 1980AJ01)] and at E_d-bar = 2.0 to 2.8 MeV (1982DE1P; also VAP). Polarization measurements have also been reported at E_d-bar = 6.3 to 15 MeV [see (1975AJ02, 1980AJ01)]. See also ⁹Be in (1984AJ01).

12. ⁹Be(t, n)¹¹B Q_m = 9.559

Angular distributions have been measured at E_t = 1.1 to 1.7 MeV (n₀, n₁, n₂, n₆, n₈, n₉): see (1980AJ01).

13. ⁹Be(³He, p)¹¹B Q_m = 10.323

Proton groups have been observed to a number of ¹¹B states: see Table 11.9 (in PDF or PS). Angular distributions have been obtained at a number of energies in the range E(³He) = 1.0 to 14 MeV [see (1980AJ01)], at E(³He) = 13.0 to 14.2 MeV (1983PO13; p₀), at E(³He) = 33 MeV (1983LE17; p₀ → p₃) and at E(³He) = 38 MeV (1982ZW02). It is suggested that the T = 1/2 strength is strongly fragmented (1982ZW02). See also (1983BI1P, 1983ZW1A).

At E(³He) = 13.6 MeV (1982HA06) find equal values for the polarization in this reaction, and the analyzing power in the ¹¹B(p, ³He) reaction, showing no violation of time-reversal invariance. This is confirmed by (1983RO22) at E(³He) = 33 MeV. See also (1981SL03, 1984PO02), (1968AJ02) and ¹²C.

14. ⁹Be(α, d)¹¹B Q_m = -8.031

Angular distributions have been measured at a number of energies in the range E_α = 23.4 to 28.3 MeV [see (1980AJ01)] and at 30.1 MeV (1983VA1H; d₀ → d₃). The predominant L-transfers are L = 0, 2; 0; 0 for ¹¹B*(0, 2.12, 5.02). The angular distribution to ¹¹B*(4.44) is flat at E_α = 27 MeV. At E_α = 48 MeV, ¹¹B*(16.44, 17.69, 18.0, 19.15) are not excited suggesting that these states are rather pure T = 3/2 states (1982ZW02): see Table 11.9 (in PDF or PS). See also (1983ZW1A).

15. ⁹Be(⁶Li, α)¹¹B Q_m = 14.341

Angular distributions have been determined for seven α-groups at E(⁶Li) = 3 to 4 MeV, and at 24 MeV to ¹¹B*(0, 2.12) and to a number of unresolved levels with E_x ≤ 13.2 MeV: see (1968AJ02, 1975AJ02). For the breakup reactions see (1975AJ02). See also (1981OS1H).

16. ¹⁰Be(p, γ)¹¹B Q_m = 11.229

The yield of γ₀ has been measured at 90° for E_p = 0.6 to 6.3 MeV. Observed resonances are displayed in Table 11.10 (in PDF or PS). T = 3/2 assignments are made for the states at E_x = 12.56, 12.91, 14.33 and 15.32 MeV whose energies match those of the first four states of ¹¹Be [compare with the T = 3/2 states reported in ⁹Be(³He, p)¹¹B - Table 11.9 (in PDF or PS)]. See also Table 11.16 (in PDF or PS). Several known T = 1/2 states in ¹¹B are not observed in this reaction: see Table 11.4 (in PDF or PS) (1970GO04, 1973GO09).

17. ¹⁰B(n, γ)¹¹B Q_m = 11.454

The thermal capture cross section is 0.5 ± 0.2 b (1981MUZQ). For a listing of the observed capture γ-rays see Table 11.12 (in PDF or PS) in (1975AJ02). See also (1980AJ01).

18. (a) ¹⁰B(n, n)¹⁰B E_b = 11.454
(b) ¹⁰B(n, n')¹⁰B*

The scattering amplitude (bound) a = -0.2 ± 0.4 fm, σ(free) = 2.23 ± 0.06 b (1983KO17). The total scattering cross section is constant at 2.23 ± 0.06 b for E_n = 0.7 to 10 keV and then rises to 2.97 b at E_n = 127 keV.

Total cross-section measurements in the range E_n = 10 to 500 keV show a broad maximum near E_n = 0.23 MeV, also observed in the (n, α) cross section. At higher energies the total cross section shows broad maxima at E_n = 1.9, 2.8 and 4.3 MeV: see Table 11.11 (in PDF or PS). In the range E_n = 5.5 to 16 MeV σ_tot is constant at 1.5 b. See also (1983DA22).

Polarization measurements (0.075 to 2.2 MeV and 2.63 MeV) and measurements of differential cross sections (0.075 to 4.4 MeV) have been analyzed using R-matrix calculations: the results are shown in Table 11.12 (in PDF or PS). They are consistent with results from ¹⁰B(n, n'γ) and ⁷Li(α, n). See (1980AJ01) for references.

Elastic and inelastic cross sections have also been reported at E_n = 4 to 14.1 MeV: see (1980AJ01). The yield of 0.7 MeV γ-rays has been studied from threshold to E_n = 5.2 MeV: observed resonances are displayed in Table 11.11 (in PDF or PS). Inelastic scattering cross sections for formation of various ¹⁰B states have been measured at a number of energies in the range E_n = 1.45 to 14.8 MeV: see (1975AJ02). See also ¹⁰B in (1984AJ01), (1979CZ1A) and (1979GLZV; theor.).

19. (a) ¹⁰B(n, p)¹⁰Be Q_m = 0.2255 E_b = 11.454
(b) ¹⁰B(n, d)⁹Be Q_m = -4.3620
(c) ¹⁰B(n, t)⁴He⁴He Q_m = 0.3217

The cross section for reaction (c) has been measured for E_n = 1.4 to 8.2 MeV: see (1968AJ02) and Table 11.11 (in PDF or PS). See also (1980AJ01).

20. ¹⁰B(n, α)⁷Li Q_m = 2.790 E_b = 11.454

The "recommended" value of the thermal isotropic absorption cross section is 3837 ± 9 b (1981MUZQ). The α₀/α₁ branching for thermal neutrons is (6.733 ± 0.008)% (1967DE15), (6.699 ± 0.012)% (1979ST03). At E_n = 2 and 24 keV the values are (7.05 ± 0.16)% and (7.13 ± 0.15)%, respectively (1979ST03).

The cross section for this reaction has been measured for E_n = 1.0 to 14.8 MeV [see (1975AJ02, 1980AJ01)] and at 0.025 eV to 25 keV (1980BO1V), 0.5 eV to 10 keV (1979CA1C, 1980CA1R) and 98 to 2200 keV (1979VI04). Evaluations of the cross-section data are presented by (1978LI32, 1981IN1B, 1982HA1Y). For observed resonances see Tables 11.11 (in PDF or PS) and 11.12 (in PDF or PS).

Parity violation has been studied using polarized thermal neutrons: a small left-right asymmetry had been reported in the (pol. n, α₀) reaction (1979BO1E, 1981VE08). However, (1984VEZW) find a_p < 8 × 10^-6 and < 1.5 × 10^-6, respectively for the transitions to ⁷Li*(0, 0.48). See also ⁷Li in (1984AJ01), (1979BO1Q, 1980CZ1A) and (1977WA1B).

21. ¹⁰B(p, π⁺)¹¹B Q_m = -128.895

Angular distributions have been obtained at E_p = 168 to 186 MeV [see (1980AJ01)] and at 154.5 MeV (1981SJ02; to ¹¹B*(0, 2.12, 4.44; also A_y), 320, 410, 483 and 605 MeV (1980DI02, 1981CO1L; to ¹¹B*(0, 2.12)) and 800 MeV (1981NAZY, 1982NA1K; to ¹¹B*(0, 2.12, 4.44, 5.02, 6.74 + 6.79, 7.29)). At E_p = 200 MeV the relative yields to ¹¹B*(0, 2.12, 4.44, 5.02, 6.74 + 6.79, 7.29, 8.0, 8.56, 8.92, 9.19 + 9.28) have been measured: they are similar to the relative yields in the (d, p) reaction except that ¹¹B*(8.93, 9.19 + 9.27) are much less strongly excited in the (p, π⁺) reaction (1980SO05). (1979MA38, 1979MA39) have measured the cross section for π⁺ production near threshold. See also (1979ME2A, 1980AJ01, 1981AU1C, 1982CO1J, 1982HO1C, 1982LE1L, 1982WA1G).

22. ¹⁰B(d, p)¹¹B Q_m = 9.230

Reported proton groups are displayed in Table 11.14 (in PDF or PS) of (1980AJ01). Angular distributions have been studied at many energies in the range E_d = 0.17 to 28 MeV [see (1968AJ02, 1975AJ02, 1980AJ01)]. See also (1983HA1Q). The lowest five levels are formed by l_n = 1 except for ¹¹B*(2.12) which appears to involve a spin-flip process. They are presumed to comprise the set 3/2^-, 1/2^-, 5/2^-, 3/2^-, 7/2^- expected as the lowest p⁷ levels (a/K ≈ 4.0). ¹¹B*(9.19, 9.27) [J^π = 7/2⁺, 5/2⁺] show strong l_n = 0 stripping and are ascribed to capture of a 2s neutron by ¹⁰B: see (1968AJ02) for a listing of all the relevant references. Studies of pγ correlations are discussed in reaction 14 of (1968AJ02) and displayed in Table 11.5 (in PDF or PS) of this paper. See also ¹²C and (1978CO1D, 1980BO1T, 1981CE04) and (1982GO05; theor.).

23. ¹⁰B(t, d)¹¹B Q_m = 5.197

At E_t = 5.5 MeV deuteron groups are observed to ¹¹B*(0, 2.12, 4.44, 5.02, 6.74, 6.79, 7.29). All the angular distributions appear to be characteristic of l_n = 1: see (1968AJ02). See also (1980BO1T).

24. ¹⁰B(α, ³He)¹¹B Q_m = -9.124

Angular distributions have been measured at E_α = 56 MeV for the ground-state transitions in this, and in the analog (α, t) reactions: the average ratio of the (α, ³He) to the (α, t) differential cross sections is 1.2 ± 0.1: see (1975AJ02).

25. ¹⁰B(⁷Li, ⁶Li)¹¹B Q_m = 4.204

At E(⁷Li) = 24 MeV angular distributions are reported to ¹¹B*(0, 6.74, 8.92). ¹¹B*(4.44, 5.02) are also populated. The (⁷Li, ⁶He) reaction [see reaction 15 in ¹¹C] has also been studied: see (1980AJ01).

26. ¹⁰B(⁹Be, ⁸Be)¹¹B Q_m = 9.789

The total reaction cross section for ⁹Be + ¹⁰B has been studied for E(¹⁰B) = 2.2 to 10.4 MeV: at low energies there is evidence for this neutron transfer reaction with the excitation of ¹¹B*(8.92, 9.19) (1979CH22).

27. ¹⁰B(¹³C, ¹²C)¹¹B Q_m = 6.508

Total cross-section measurements involving ¹¹B*(4.44, 6.74) have been carried out for E(¹³C) = 4.2 to 13.3 MeV: see (1980AJ01) and (1983DA20).

28. ¹¹Be(β^-)¹¹B Q_m = 11.508

¹¹Be decays to many states of ¹¹B: see Table 11.13 (in PDF or PS) for the observed β^- and γ-transitions (1982MI08). ¹¹B*(9.88) decays via α-emission to ⁷Li*(0, 0.48) with branching ratios (87.4 ± 1.2)% and (12.6 ± 1.2)%, respectively (1981AL03). A study of the βν angular correlation in the first-forbidden decay of ¹¹Be to the 1/2^- state ¹¹B*(2.12) has been performed: the β-transition is dominated by rank-0 matrix elements and is of interest as a test of meson-exchange effects (1982WA18). See also (1980RI06; theor.).

29. (a) ¹¹B(γ, n)¹⁰B Q_m = -11.454
(b) ¹¹B(γ, p)¹⁰Be Q_m = -11.229
(c) ¹¹B(γ, d)⁹Be Q_m = -15.816
(d) ¹¹B(γ, t)⁸Be Q_m = -11.224

The giant dipole resonance is shown to consist mainly of T = 1/2 states in the lower-energy region and of T = 3/2 states in the higher energy region by observing the decay to states in ¹⁰B and ¹⁰Be (reactions (a) and (b)). Absolute measurements of the ¹¹B(γ, all n) cross section have been carried out from threshold to 35 MeV: the cross section exhibits a main peak at E_γ = 25 to 28 MeV and weak shoulders at 13 and 16 MeV. The integrated cross section to 35 MeV is 69.1 ± 0.8 MeV · mb: see (1980AJ01). (1979KA35) report the transition to ¹⁰B*(1.74). For other structures reported in the (γ, n) and (γ, p) cross sections see (1975AJ02). The (γ, d₀) cross section peaks at ≈ 19 MeV, lower than it would if T = 3/2 states were involved. The yield of 3.37 MeV γ-rays (from ¹⁰Be*(3.37), reaction (b)) has been measured for E_bs = 100 to 800 MeV.

For reaction (d) see (1983IS1D). See (1980AJ01) for references and for other photonuclear processes. See also (1980DU21, 1982DU1A, 1982GO03, 1983GO1T; theor.).

30. ¹¹B(γ, γ)¹¹B

Widths of excited states are shown in Table 11.14 (in PDF or PS). See also (1980MO14) and (1980AJ01).

31. (a) ¹¹B(e, e')¹¹B*
(b) ¹¹B(e, ep)¹⁰Be Q_m = -11.229

Magnetic elastic scattering at θ = 180° shows strong M3 effects: the derived ratio of static M3/M1, 2.9 ± 0.2 fm², suggests a jj-coupling scheme for ¹¹B_g.s.. The quadrupole contribution to the elastic form factor is best accounted for by the undeformed shell model, Q = 3.72 (± 20%) fm², r(rms) = 2.42 fm. [From muonic X-rays < r² > ^1/2 = 2.47 ± 0.04 fm.] See (1980AJ01) for references. The excitation of ¹¹B*(2.1, 4.4, 5.0, 8.6, 8.9) has been studied by (1975KA02: E_e = 52 to 90 MeV). The giant-resonance region, centered at ≈ 18 MeV, is characterized by a lack of prominent features except for a pronounced peak at E_x = 13.0 ± 0.1 MeV (mixed M1 - E2) and a broad transverse group at E_x = 15.5 MeV (1975KA02). At E_e = 121, 186 and 250 MeV form factors (and B(Eλ)↑) are obtained for ¹¹B*(4.4, 6.7, 8.5, 8.9, 13.00 ± 0.15) and the excitation of ¹¹B*(14.50 ± 0.15, 16.7 ± 0.2) is also reported (1979PO1B).

For Γ_γ₀ see Table 11.14 (in PDF or PS). For reaction (b) see (1975AJ02). See also (1979RI1D), (1981RI1A) and (1981KE17, 1982BO1H, 1982KE1C, 1983AL04; theor.).

32. ¹¹B(π⁺, π⁺)¹¹B

The proton matter distribution in ¹¹B_g.s. has a radius of 2.368 ± 0.021 fm, assuming that for ¹²C to be 2.44 fm. The result is not sensitive to the details of the optical-model calculations (1980BA45; E_π⁺ = 38.6 and 47.7 MeV). See also the "General" section here.

33. ¹¹B(n, n')¹¹B*

Angular distributions have been reported for E_n = 4 to 14.1 MeV [see (1980AJ01)] and at 2.6 to 8.0 MeV (1980WH01; n₀), 4.86 to 7.55 MeV (1983KO03; n₀, n₁ and, at the higher energies, n₂, n₃) and at 8 to 14 MeV (1983DA22). See also ¹²B, and (1979GLZV, 1983KO1F; theor.).

34. ¹¹B(p, p')¹¹B*

Observed proton groups are displayed in Table 11.15 (in PDF or PS). Angular distributions have been measured for E_p = 6 to 185 MeV [see (1980AJ01)] and at 1 GeV (1979AL26). See also (1980FA07). The analysis of the 3/2^- → 1/2^- transition [¹¹B*(0 → 2.12) at E_{pol. p} = 32 MeV shows less spin-flip than predicted by DWBA (1981CO08). See also ¹²C, (1981HO13) and (1979RO1B, 1980KO1V; theor.).

35. ¹¹B(d, d)¹¹B

The elastic scattering has been studied at E_d = 5.5 MeV and 11.8 MeV: see (1980AJ01).

36. ¹¹B(t, t)¹¹B

The elastic scattering has been studied at E_t = 1.8 and 2.1 MeV: see (1980AJ01).

37. ¹¹B(³He, ³He)¹¹B

The elastic scattering has been studied at E(³He) = 8 to 74 MeV: see (1975AJ02, 1980AJ01). At E(³He) = 17.5 and 40 MeV angular distributions have also been studied for the ³He ions to ¹¹B*(2.12, 4.44, 5.02, 6.74) (1977SH09). T = 3/2 states observed in this reaction are displayed in Table 11.16 (in PDF or PS). There is a weak indication also of a state at E_x = 14.51 MeV: see (1975AJ02).

38. ¹¹B(α, α')¹¹B

Angular distributions have been reported at E_α = 24 to 29.0 MeV [see (1975AJ02, 1980AJ01)] and at 31.2 MeV (1981KO1U; α₀).

39. (a) ¹¹B(⁶Li, ⁶Li)¹¹B
(b) ¹¹B(⁷Li, ⁷Li)¹¹B

The elastic scattering has been studied at E(⁶Li) = 28 MeV: see (1975AJ02). For reaction (b) see (1983STZS).

40. (a) ¹¹B(⁹Be, ⁹Be)¹¹B
(b) ¹¹B(¹⁰B, ¹⁰B)¹¹B
(c) ¹¹B(¹¹B, ¹¹B)¹¹B

See (1975AJ02, 1980AJ01) and (1983DU13).

41. (a) ¹¹B(¹²C, ¹²C)¹¹B
(b) ¹¹B(¹³C, ¹³C)¹¹B

The elastic scattering has been studied at E(¹¹B) = 18.8 to 34.1 MeV and at E(¹²C) = 15 to 24 MeV and at 87 MeV [see (1980AJ01)] as well as at E(¹¹B) = 25, 40 and 50 MeV (1982MA20) and 28 MeV (1983SR01). The population of ¹¹B*(2.12, 4.44, 6.79) and of ¹²C*(0, 4.43) are also reported. For yield and fusion studies see (1979FR05, 1981MA18, 1982MA20, 1983MA53, 1984MAZZ) for reaction (a) and (1983DA20) for reaction (b). See also (1982FR1T, 1983BI13, 1983DU13) and (1978DZ1A, 1979IS07, 1979ZE1B, 1981YO05, 1982HA42; theor.).

42. ¹¹B(¹⁴N, ¹⁴N)¹¹B

The elastic scattering has been investigated at E(¹⁴N) = 41, 77 and 133 MeV: see (1975AJ02). For fusion cross sections see (1983DA10).

43. (a) ¹¹B(¹⁶O, ¹⁶O)¹¹B
(b) ¹¹B(¹⁸O, ¹⁸O)¹¹B

The elastic scattering in reaction (a) has been studied at E(¹⁶O) = 14.5 to 60 MeV and at E(¹¹B) = 115 MeV [see (1975AJ02, 1980AJ01)] as well as at E(¹¹B) = 41.6 and 49.5 MeV (1980PA01). A study of the elastic scattering in reaction (b) is reported at E(¹¹B) = 115 MeV (1980PR09). See also (1983GO13; theor.).

44. ¹¹B(²⁰Ne, ²⁰Ne)¹¹B

The elastic angular distribution has been obtained at E(¹¹B) = 115 MeV (1981GO11).

45. (a) ¹¹B(²⁴Mg, ²⁴Mg)¹¹B
(b) ¹¹B(²⁵Mg, ²⁵Mg)¹¹B
(c) ¹¹B(²⁶Mg, ²⁶Mg)¹¹B
(d) ¹¹B(²⁷Al, ²⁷Al)¹¹B

The elastic scattering angular distributions have been studied at E(¹¹B) = 79.6 MeV (1982FU09).

46. ¹¹B(⁴⁰Ca, ⁴⁰Ca)¹¹B

Angular distributions are reported at E(¹¹B) = 51.5 MeV to ¹¹B*(0, 2.12) (1980GL03, 1981HN01).

47. ¹¹C(β⁺)¹¹B Q_m = 1.982

See ¹¹C.

48. ¹²C(μ, nν)¹¹B Q_m = 88.921

The γ-decay of ¹¹B*(2.12) has been observed (1981GI08).

49. (a) ¹²C(γ, p)¹¹B Q_m = -15.956
(b) ¹²C(e, p)¹¹B Q_m = -15.956

The fraction of transitions to the ground and to excited states of ¹¹B (and to ¹¹C states reached in the (γ, n) reaction) has been measured at E_bs = 21.7 to 42 MeV: the ground state is predominantly populated [see (1980AJ01) and (1980IS1F)]. The population of analog states in the (γ, n) and (γ, p) reactions are similar: see ¹¹C. Differential cross sections for populating several states of ¹¹B have been measured at E_γ = 21.7 → 31 MeV (1980IS1F) and at 60, 80 and 100 MeV: see (1980AJ01). The cross section for reaction (b) has been measured for E_e = 21, 25, 35, 45 and 55 MeV. The production of ¹¹B in astrophysical sites with large densities of high-energy electrons is discussed by (1983HO15). See also ¹²C, (1979KI04), (1980GO13), (1982SC1E; astrophys.) and (1981BO14, 1982LO08, 1983OR03; theor.).

50. ¹²C(e, ep)¹¹B Q_m = -15.956

At E_e = 497 MeV ¹¹B*(0, 2.1, 5.0) are populated: l = 1: see (1980AJ01). See also ¹²C and (1979MO1G, 1980CA1L, 1982BE02, 1983MO1F) and (1983KL04; theor.).

51. ¹²C(π⁺, π⁺p)¹¹B Q_m = -15.956

At E_π⁺ = 100 MeV [and 129.7 to 199.8 MeV (1981ZI01)] the reaction proceeds primarily to ¹¹B_g.s.. At E_π = 200 MeV the ratios for σ_n/σ_p for the first excited states in ¹¹C/¹¹B are 1.4 ± 0.2 for π^- and 1/1.8 ± 0.2 for π⁺. At E_π⁺ = 60 to 300 MeV ¹¹B*(4.44) [J^π = 5/2^-] is strongly populated, as is the analog state in the mirror reaction. See (1980AJ01) for references. See also reaction 21 in ¹¹C, ¹²C, (1983HUZZ, 1983MO1F) and (1982CH13; theor.). For the reaction ¹²C(π^-, n)¹¹B see (1983CE04).

52. ¹²C(p, 2p)¹¹B Q_m = -15.956

At E_p = 98.7 MeV well-resolved groups are observed to ¹¹B*(0, 2.12, 4.44, 5.02, 6.79). DWIA calculations lead to relative spectroscopic factors of 2.0, 0.37, 0.15, 1.08, 0.25 for these states [normalized to 2.0 for ¹¹B_g.s.; overlap calculation]. No evidence is seen for the formation of giant resonances as the intermediate step in multistep reaction processes to ¹¹B*(4.44, 6.74) (1979DE35). For the earlier work see (1975AJ02, 1980AJ01). See also (1983CH1B) and (1981AM01, 1983IK03; theor.).

53. ¹²C(d, ³He)¹¹B Q_m = -10.463

Angular distributions of ³He ions have been measured for E_d = 20 to 80 MeV: see (1975AJ02, 1980AJ01). reported C²S for ¹¹B_g.s. are 3.22 or 4.42 depending on the choice of parameters (1978CO13; E_d = 29 MeV; see also (d, t) results - reaction 24 in ¹¹C) while (1975MA41; E_d = 52 MeV) find 2.98, 0.69, 0.31 for ¹¹B*(0, 2.12, 5.02). For a polarization study see (1981MA14). See also ¹⁴N in (1986AJ01) and (1982ST1A; theor.).

54. ¹²C(t, α)¹¹B Q_m = 3.858

Angular distributions have been measured for E_t = 1 to 3.4, 10.1 and 13 MeV: see (1975AJ02).

55. ¹²C(α, ⁵Li)¹¹B Q_m = -17.92

At E_α = 65 MeV, ¹¹B*(0, 2.12, 6.74 + 6.79) are strongly populated (1978SA26).

56. ¹²C(¹²C, ¹³N)¹¹B Q_m = -14.013

Angular distributions involving the ground-state transitions have been measured at E(¹²C) = 93.8 MeV (1979FU04) and 114 MeV (1974AN36). For yield measurements see (1980CO10). See also (1981CH1R) and (1981XU1A; theor.).

57. ¹²C(¹⁹F, ²⁰Ne)¹¹B Q_m = -3.108

At E(¹⁹F) = 40, 60 and 68.8 MeV angular distributions involving ¹¹B*(0, 2.12) and ²⁰Ne*(0, 1.63) have been measured: see (1980AJ01).

58. ¹³C(p, ³He)¹¹B Q_m = -13.184

At E_p = 50.5 MeV, in addition to ¹¹B*(0, 2.12, 4.44, 5.02, 6.74, 8.92), a state is observed at E_x = 12.94 ± 0.05 MeV, Γ = 350 ± 50 keV. Comparison of the angular distributions of the ³He and of the tritons [in the analog reaction] at E_p = 43.7 and 50.5 MeV lead to the assignments J^π = 1/2^-, T = 3/2 for this state and for ¹¹C*(12.50): the strong proton and the weak α-decay are consistent with this assignment: see Table 11.16 (in PDF or PS). Angular distributions have been measured at E_p = 26.9 to 49.6 MeV, involving the states above except for ¹¹B*(8.92) [see (1975AJ02, 1980AJ01)] and at E_{pol. p} = 65 MeV (1982KA01; to ¹¹B*(0, 2.12); also analyzing power). See also ¹⁴N in (1986AJ01).

59. ¹³C(d, α)¹¹B Q_m = 5.169

Observed proton groups are displayed in Table 11.15 (in PDF or PS). Angular distributions are reported at E_d = 0.41 to 14.1 MeV: see (1975AJ02).

60. ¹⁴C(p, α)¹¹B Q_m = -0.783

At E_p = 41.9 MeV angular distributions have been studied for the groups to ¹¹B*(0, 2.12, 4.44, 6.74) (1983AR1K). See also (1968AJ02).

61. (a) ¹⁴N(n, α)¹¹B Q_m = -0.157
(b) ¹⁴N(n, 2α)⁷Li Q_m = -8.822

Angular distributions have been measured for E_n = 4.9 to 18.8 MeV [see (1975AJ02, 1980AJ01)] and at E_n = 12.2, 14.1 and 18 MeV (1978BU28; α₀). At E_n = 14.1 and 15.7 MeV various states of ¹¹B with 8.9 < E_x < 14.5 MeV appear to be involved in the sequential decay to ⁷Li. Angular correlation results are consistent with J = 7/2 and 5/2 for ¹¹B*(9.19, 9.27) respectively: see (1975AJ02).

62. ¹⁵N(α, ⁸Be)¹¹B Q_m = -11.082

See (1980AJ01).

63. ¹⁶O(d, ⁷Be)¹¹B Q_m = -16.037

At E_d = 80 MeV angular distributions have been measured to ¹¹B*(0, 2.12, 4.44 + 5.02, 6.74 + 6.79 + 7.29) (1978OE1A). See also (1984NE1A).

64. ¹⁶O(¹⁰B, ¹¹B)¹⁵O Q_m = -4.210

See (1983OS08; theor.).