A=11C (1985AJ01)

The half-life of ¹¹C is 1223.1 ± 1.2 sec (This value may not be correct, see Erratum to this publication). Log ft = 3.599 ± 0.002. The ratio of K-capture to positron emission is (0.230^+0.014_-0.011)%. See (1980AJ01) for references. See also (1980RA16), (1984BO1C; astrophys.), (1982KA1C; applied) and (1980AF1A; theor.).

2. ⁶Li(⁶Li, n)¹¹C Q_m = 9.450

At E(⁶Li) = 4.1 MeV angular distributions have been obtained for the neutrons to ¹¹C*(2.00, 4.32, 4.80, 6.34 + 6.48, 6.90, 7.50). In addition, nγ coincidences via ¹¹C*(8.42) [and an 8.42 MeV γ-ray] are reported. ¹¹C*(8.10) was not observed. The lifetimes, τ_m, for ¹¹C*(4.32, 6.90, 7.50) are < 140, < 69 and < 91 fsec, respectively. See (1980AJ01) for references.

3. ⁷Be(α, γ)¹¹C Q_m = 7.544

At the resonances at E_α = 0.884 ± 0.008 and 1.376 ± 0.003 MeV [¹¹C*(8.107, 8.420)] ωγ = 0.331 ± 0.041 and 3.80 ± 0.57 eV, Γ_γ = 0.350 ± 0.056 and 3.1 ± 1.3 eV for these two states and Γ_α = 6⁺¹²_-2 and 12.6 ± 3.8 eV, respectively (1984HA13).

4. ⁹Be(³He, n)¹¹C Q_m = 7.558

Reported neutron groups are listed in Table 11.16 (in PDF or PS) of (1968AJ02). Angular distributions have been studied in the range E(³He) = 1.3 to 13 MeV: see (1980AJ01). The dominant L-values are 0 for ¹¹C*(0, 8.10), 1 for ¹¹C*(6.34, 7.50), 2 for ¹¹C*(2.00, 4.32, 4.80, 6.48, 8.42) and 3 for ¹¹C*(6.90). Neutron groups to T = 3/2 states have been reported at E_x = 12.17 ± 0.05 [see, however, reaction 30], 12.55 ± 0.05 MeV and 14.7 ± 0.1 MeV: see Table 11.19 (in PDF or PS).

Gamma branching ratios and multipolarities for ¹¹C levels up to E_x = 7.5 MeV have been studied by (1965OL03): see Table 11.18 (in PDF or PS). Together with evidence from reactions 12 and 23 they lead to assignments of J^π = 1/2^-, 5/2^-, 3/2^-, 1/2⁺, 7/2^-, 5/2⁺, 3/2⁺ for ¹¹C*(2.00, 4.32, 4.80, 6.34, 6.48, 6.90, 7.50): see (1965OL03) and reaction 3 in (1968AJ02) for a summary of the evidence concerning these assignments. See (1980AJ01) for references. See also ¹²C, (1981AN16, 1982MCZZ), (1979WA1F; applied) and (1981OS1H).

5. ¹⁰B(p, γ)¹¹C Q_m = 8.690

This reaction has been investigated for E_p = 0.07 to 17.0 MeV. Reported resonances are displayed in Table 11.20 (in PDF or PS). Observed capture γ-rays are displayed in Table 11.18 (in PDF or PS) [see also for τ_m measurements]. Capture measurements for E_p = 0.07 to 2.20 MeV are consistent with five new resonances (see Tables 11.20 (in PDF or PS) and 11.18 (in PDF or PS)), the lowest two (at E_p = 10 and 560 keV) of which are s-wave resonances. Thermonuclear reaction rates for T = (0.01 → 5) × 10⁹ °K are deduced from the results (1983WI09; see also for spectroscopic factors).

The 90° yield of γ₀ has been measured for E_p = 2.6 to 17 MeV and angular distributions have been obtained for E_p = 2.8 to 14 MeV. The excitation function is consistent with the giant resonance centered at E_x ≈ 16 MeV. In addition to weak structures at E_p = 4.75 MeV and 10.5 MeV, there are three major peaks at E_p = 4.1, 7.0 and 8.8 MeV (Γ = 1 - 2 MeV) [E_x = 12.4, 15.0, 16.7 MeV]. At ¹¹C*(12.4), the γ₀ angular distribution is essentially isotropic: Γ_pΓ_γ/Γ ≈ 200 eV, Γ_γ ≈ 5 keV (assuming Γ_p ≈ 10 keV). The E_p = 4.1 MeV resonance is probably part of the E1 giant resonance and is formed by s-wave capture. At the two higher resonances the angular distributions are characteristic of E1 giant resonances in light nuclei. The ¹⁰B(p, γ₁) cross section is small for E_p = 2.6 to 17 MeV (1970KU09). See also (1979RO12; applied).

6. ¹⁰B(p, n)¹⁰C Q_m = -4.431 E_b = 8.690

The total (p, n) cross section has been measured to E_p = 10.6 MeV: broad maxima are observed at E_p = 5.92 ± 0.02, 6.68 ± 0.04, 7.33 ± 0.05 and 7.60 ± 0.05 MeV (see Table 11.20 (in PDF or PS)). The cross section for formation of ¹⁰C_g.s. measured up to 12 MeV shows similar behavior to 8 MeV. At E_p ≈ 8 MeV, a sharp maximum is observed. The cross section for production of 3.35 MeV γ-rays (from ¹⁰C*) does not appear to show structure for E_p = 8.5 to 12 MeV. For references see (1980AJ01). See also ¹⁰C in (1984AJ01) and (1979BA68).

7. ¹⁰B(p, p)¹⁰B E_b = 8.690

Below E_p = 0.7 MeV the scattering can be explained in terms of pure s-wave potential scattering but the possibility of a state near E_p = 0.27 MeV (E_x = 8.95 MeV) cannot be excluded. The elastic scattering then shows two conspicuous anomalies at E_p = 1.50 ± 0.02 MeV and at 2.18 MeV [E_x = 10.05 and 10.67 MeV] with J^π = 7/2⁺ and 9/2⁺: see Table 11.20 (in PDF or PS). At higher energies (to E_p = 10.5 MeV) a single broad resonance is reported at E_p ≈ 5 MeV. The yield of p₀ has also been measured at θ = 150° for E_p = 5.4 to 7.5 MeV (1981HO13). Polarization measurements are reported at 30.3 MeV (1976DE15, 1977PH02): optical-model parameters are derived. The depolarization parameter D has been measured for polarized protons with E_p = 26 and 50 MeV. For references see (1980AJ01).

8. ¹⁰B(p, p')¹⁰B E_b = 8.690

The yield of γ₁ [from ¹⁰B*(0.72)] rises monotonically from E_p = 1.5 to 4.1 MeV and then shows resonance behavior at E_p = 4.36 and 5.73 MeV: see Table 11.20 (in PDF or PS). For E_p = 6 to 12 MeV, the cross section for γ₁ shows several sharp maxima superposed on a broad maximum (Γ ≈ 2.5 MeV) at E_p ≈ 7.2 MeV. See however (1975AJ02). Yields of five other γ-rays involved in the decay of ¹⁰B*(1.74, 2.16, 3.59, 5.18) have also been measured in the range E_p = 4 to 12 MeV [see (1975AJ02)]. The yield of 0.72 MeV γ-rays has been studied for E_p = 2.0 to 4.1 MeV: no resonances are observed (1979RI12).

Excitation curves for the p₁, p₂ and p₃ groups have been measured for E_p = 3.5 to 5.0 MeV. Possible resonances are observed in the p₂ yield [to the T = 1 state ¹⁰B*(1.74)] corresponding to the first T = 3/2 states at E_x = 12.16 [see, however, reaction 30] and 12.50 MeV [see Table 11.19 (in PDF or PS)]: these do not occur in the yield of p₁ and p₃. Yield curves for inelastically scattered protons have also been measured at E_p = 5.0 to 16.4 MeV (p₁, p₂, p₃), 6.6 to 16.4 MeV (p₄), 8.9 to 16.4 MeV (p₅) and 10.9 to 16.4 MeV (p to ¹⁰B*(6.03)): the principal feature for all groups, except that to ¹⁰B*(6.03), is a structure at E_p ≈ 7.5 MeV, Γ ≈ 4 MeV. In addition narrower structures are observed, including three at E_p = 5.75, 6.90 and 7.80 MeV (± 0.2 MeV) and widths of ≈ 500 keV. For π⁺ production see (1980DI02, 1981CO1L, 1982LO1K). See also (1979GLZV; theor.) and ¹⁰B in (1984AJ01).

9. ¹⁰B(p, d)⁹B Q_m = -6.212 E_b = 8.690

Polarization measurements have been carried out at E_p = 49.6 MeV for the deuterons to ⁹B*(0, 2.36): see (1975AJ02).

10. ¹⁰B(p, ³He)⁸Be Q_m = -0.5339 E_b = 8.690

Two strong maxima are observed at E_p ≈ 4.5 and 6.5 MeV: see Table 11.20 (in PDF or PS). See also (1975AJ02).

11. ¹⁰B(p, α)⁷Be Q_m = 1.146 E_b = 8.690

The total cross section for this reaction has been measured for E_p = 60 to 180 keV: the extrapolated cross section at the Gamow energy, taken to be 19.1 keV, is ≈ 10^-12 b. The thick-target yield for E_p = 75 keV to 3 MeV has been measured by (1975PE1A): the ⁷Be yield constitutes a potential problem if natural boron is ussed as fuel in CTR devices.

The parameters of observed resonances are displayed in Table 11.20 (in PDF or PS). The ground-state (α₀) α-particles exhibit broad resonances at E_p = 1.17, 1.53, 2.18, 3.0, 4.4, 5.1 and 6.3 MeV. Alpha particles to ⁷Be*(0.43) [α₁] and 0.43 MeV γ-rays exhibit all but the 1.2 MeV resonance: see (1975AJ02). A broad maximum dominates the region from E_p = 4 MeV to about 7.5 MeV. A recent study of the yeild of 0.43 MeV γ-rays for E_p = 2.0 to 4.1 MeV suggests that the 3.0 MeV resonance, which is asymmetric, is due to two broad states. A weak structure at E_p = 2.5 MeV is also reported (1979RI12). See also ⁷Be in (1984AJ01), (1979RA20) for the cross section at E_p = 740 MeV for ⁷Be production, (1979RO12; applied) and (1983LE28, 1983SZZY; astrophys.).

12. ¹⁰B(d, n)¹¹C Q_m = 6.465

Table 11.21 (in PDF or PS) presents the results obtained in this reaction and in the (³He, d) reaction. Information on τ_m and on the γ-decay of ¹¹C states is displayed in Table 11.18 (in PDF or PS): see (1968AJ02, 1975AJ02) for references. See also (1981AN16), (1979LE1D; applied) and ¹²C.

13. ¹⁰B(³He, d)¹¹C Q_m = 3.196

Table 11.21 (in PDF or PS) displays the information derived from this reaction and from the (d, n) reaction. The study of the angular distributions of the deuterons to ¹¹C*(8.66, 8.70) shows that these levels are the analogs, respectively, of ¹¹B*(9.19, 9.27) whose J^π are 7/2⁺ and 5/2⁺ [the ¹¹B states were studied in the (d, p) reaction]: Γ_c.m. are ≪ 9 keV and 15 ± 1 keV, respectively, for ¹¹C*(8.66, 8.70): see (1975AJ02) for references.

14. ¹⁰B(α, t)¹¹C Q_m = -11.124

Angular distributions have been measured at E_α = 25.1 and 56 MeV [see (1980AJ01)] and at 29.5 MeV (1982VA1F; t₀, t₁). See also (1983BE1Q; theor.).

15. ¹⁰B(⁷Li, ⁶He)¹¹C Q_m = -1.285

Angular distributions of ⁶He ions have been measured at E(⁷Li) = 3.0 to 3.8 MeV and at 24 MeV [to ¹¹C*(0, 4.32, 6.48)]. ¹¹C*(2.0, 4.80, 8.42, 8.66 + 8.70) are also populated: see (1980AJ01) for references.

16. ¹⁰B(¹⁴N, ¹³C)¹¹C Q_m = 1.139

Elastic angular distributions have been obtianed at E(¹⁴N) = 73.9 and 93.6 MeV (1979MO14).

17. ¹¹B(γ, π^-)¹¹C Q_m = -141.549

See (1976MI15, 1981RO1L).

18. ¹¹B(p, n)¹¹C Q_m = -2.764

Angular distributions have been measured at many energies up to 49.5 MeV [see (1980AJ01)] and at 5.49 to 7.29 MeV (1981HO13; n₀, n₁). ¹¹C*(4.32, 4.81, 6.33, 6.48) are also populated. See also (1981AN16, 1981MU1D), ¹²C and (1980BA11; theor.).

19. ¹¹B(³He, t)¹¹C Q_m = -2.001

Angular distributions of t₀ and t₁ have been measured at E(³He) = 10, 14 and 217 MeV [the latter also for the triton groups to ¹¹C*(4.3, 4.8, 6.48, 8.10) [see (1980AJ01)] and at E(pol. ³He) = 33 MeV (1981BA1G). At E(³He) = 26 MeV the known states of ¹¹C below E_x = 11 MeV are populated and triton groups are also observed to the possibly T = 3/2 states displayed in Table 11.19 (in PDF or PS) as well as a state at 14.15 MeV. For references see (1980AJ01).

20. ¹²C(γ, n)¹¹C Q_m = -18.721

The fraction of transitions to the ground and to excited states of ¹¹C [and to ¹¹B states reached in the (γ, p) reaction] has been measured at E_bs = 24.5, 27, 33 and 42 MeV: the ground state is predominantly populated. The population of analog states in the (γ, n) and (γ, p) reactions are similar. And a significant decay strength is found to the positive-parity states with 6 < E_x < 8 MeV. In general the main contribution to the strength of the transitions to the various excited states of ¹¹B, ¹¹C lies in rather localized energy bands in ¹²C which are a few MeV wide (1970ME17). See also reactions 24 and 25 in (1980AJ01), ¹²C, (1979KI04, 1980GA29, 1980GO13) and (1982LO08; theor.).

21. (a) ¹²C(π^±, π^±n)¹¹C Q_m = -18.721
(b) ¹²C(n, 2n)¹¹C Q_m = -18.721
(c) ¹²C(p, pn)¹¹C Q_m = -18.721

(1978MO01) report the strong population of the 5/2^- state ¹¹C*(4.32) (and of the analog state in ¹¹B) for E_π⁺ = 60 to 300 MeV. See also (1982BU20) as well as (1982HO1C) and (1980KE13; theor.). For reactions (b) and (c) see (1980AJ01), and (1980MC1E) for reaction (c). See also ¹²C.

22. ¹²C(π⁺, p)¹¹C Q_m = 121.629

Angular distributions have been obtained to ¹¹C*(0, 2.0, 4.3 + 4.8, 6.5, 8.5) by (1978AM01; E_π⁺ = 49.3 MeV) and (1981AN10; E_π⁺ = 90 and 180 MeV). At the same momentum transfer this reaction and the (p, d) reaction give similar intensities to the low-lying states of ¹¹C. (1978AM01) have also reported population of a T = 3/2 state at E_x = 12.5 ± 0.3 MeV. However (1981AN10) do not observe it: they suggest the possible excitation of ¹¹C*(13.3). See the discussion in (1982DO01). See also (1980GO16) and (1982LO1B; theor.).

23. ¹²C(p, d)¹¹C Q_m = -16.496

Angular distributions have been measured for E_p = 19 to 800 MeV [see (1968AJ02, 1975AJ02, 1980AJ01) for references] and at E_p = 52 MeV (1980OH06; d to ¹¹C*(0, 4.30, 6.48)) and at E_{pol. p} = 65 MeV (1980HO18; d₀, d₁). Observed states of ¹¹C are displayed in Table 11.24 (in PDF or PS) of (1980AJ01). See also ¹³N in (1986AJ01), (1981IR1A), (1980WH1A, 1982LO1B, 1982YA1A, 1983MO1F) and (1980CO06, 1980SA1K, 1980WI02, 1981JA1D, 1981LU1A, 1982SH06, 1983LU01; theor.).

24. ¹²C(d, t)¹¹C Q_m = -12.463

At E_d = 28 MeV the t₀ angular distribution has been measured and a detailed comparison has been made with the results for the mirror reaction ¹²C(d, ³He)¹¹B. At E_d = 29 MeV the t₀ angular distribution leads to spectroscopic factors C²S = 2.82 or 3.97 depending on different sets of parameters for ¹¹C_g.s.. ¹¹C*(2.0, 4.32) are also populated. See also ¹⁴N in (1986AJ01), and (1980AJ01) for references.

25. (a) ¹²C(³He, α)¹¹C Q_m = 1.857
(b) ¹²C(³He, tp)¹¹C Q_m = -17.957

Angular distributions have been measured at many energies to E(³He) = 217 MeV [see (1968AJ02, 1975AJ02, 1980AJ01) for references] as well as at 99.4, 119.1 and 139.6 MeV (1981TA25; α₀ → α₃, α₅). Observed states are displayed in Table 11.22 (in PDF or PS). In addition the excitation of states at E_x = 11.2, 12.4, 15.3, 23 and (28) MeV has also been suggested: see (1980AJ01).

At E(³He) = 35.6 MeV (1978FO13) find good fits by DWBA for strong l = 1 transitions, and reasonable agreement in the forward direction, as well as with S_theor., for weak l = 1 transitions. Transitions involving l = 0 or 2 (and 3) are weak and the agreement with theory is poor. It is suggested that ¹¹C*(8.10) [3/2^-] is predominantly a p_3/2 hole state coupled to ¹²C*(7.65) [0⁺] (1978FO13).

Alpha-gamma correlations have been studied for E(³He) = 4.7 to 12 MeV: see, in particular, (1968EA03). Their results are summarized in Table 11.20 (in PDF or PS) and are discussed in detail in reaction 22 of (1968AJ02). A measurement of the linear polarization of the 2.00 MeV γ-ray (together with knowledge of the τ_m) fixes J^π = 1/2^- for ¹¹C*(2.00) (1968BL09). τ_m = 10.3 ± 0.7 fsec for ¹¹C*(2.00) (1981AL1C). See also ¹²N, ¹⁵O in (1981AJ01, 1986AJ01), (1983MO1F) and (1982KU17; theor.).

Reaction (b) has been studied at E(³He) = 75 MeV: transitions to ¹¹C*(0, 2.0, 4.3, 4.8, 6.3) are observed by looking at p, t angular correlations (1983ST10).

26. ¹²C(⁶Li, ⁷Li)¹¹C Q_m = -11.471

The angular distributions involving ⁷Li_g.s. + ¹¹C_g.s. and ⁷Li*_0.48 + ¹¹C*_2.00 have been studied at E(⁶Li) = 36 MeV: see (1980AJ01).

27. ¹²C(¹⁰B, ¹¹B)¹¹C ^§ Q_m = -7.266
^§ I am indebted to Dr. F.C. Barker for his comments on this reaction.

At E(¹⁰B) = 100 MeV, angular distributions have been measured involving ¹¹B_g.s. + ¹¹C_g.s., ¹¹B_g.s. + ¹¹C_2.00 and ¹¹C_g.s. + ¹¹B_2.12. Both ¹²C(¹⁰B, ¹¹B)¹¹C (with ¹¹B detected in the forward direction) and ¹²C(¹⁰B, ¹¹C)¹¹B (with ¹¹C detected in the forward direction) were measured. In each case, ¹¹B_g.s. + ¹¹C_2.00 and ¹¹C_g.s. + ¹¹B_2.12 were not resolved, but the authors (1975NA15) argue that the (¹⁰B, ¹¹B) case would have little contribution from ¹¹C_g.s. + ¹¹B_2.12 (because of the spins of ¹⁰B and ¹¹B_2.12), so that it essentially gives the ¹¹B_g.s. + ¹¹C_2.00 angular distribution, and similarly for the other case.

28. ¹²C(¹²C, ¹³C)¹¹C Q_m = -13.774

Angular distributions involving ¹¹C_g.s. have been studied at E(¹²C) = 114 MeV [see (1980AJ01)] and at 93.8 MeV (1979FU04). Cross sections for production of ¹¹C at E(¹²C) = 0.40, 1.05 and 2.1 GeV/nucleon are reported by (1983SM03). See also (1981CH1R).

29. ¹³C(π⁺, d)¹¹C Q_m = 118.907

At E_π⁺ = 32 MeV angular distributions have been obtained for the deuterons to ¹¹C*(0, 6.48) (1982DO01).

30. ¹³C(p, t)¹¹C Q_m = -15.185

At E_p = 43.7 to 50.5 MeV angular distributions of the tritons have been studied to ¹¹C*(0, 2.00, 4.32, 4.80, 6.48, 6.90, 7.50) and to a T = 3/2 state at E_x = 12.47 MeV [see Table 11.19 (in PDF or PS)] whose J^π is determined to be 1/2^- [it is thus the analog of ¹¹Be*(0.32)]. The state decays primarily by p → ¹⁰B*(1.74). Alpha decay to ⁷Be*_g.s. + 0.4 is also observed. Angular distributions have also been measured for E_p = 26.9 to 43.1 MeV [see (1980AJ01)] and at E_p = 65 MeV (1982KA01; t₀, t₁). At E_p = 46.7 MeV the T = 3/2 state is also observed by (1974BE20) who, in addition, report the population of states with E_x = 11.03 ± 0.03, 13.33 ± 0.06, 13.90 ± 0.04 and 14.07 ± 0.04 MeV [Γ = 300 ± 60, 270 ± 80, 150 ± 50 and 135 ± 50 keV, respectively]. However, the T = 3/2 state at E_x = 12.16 MeV reported by (1971WA21) in reactions 4, 8 and 19 is not observed by (1974BE20).

31. ¹⁴N(p, α)¹¹C Q_m = -2.922

Angular distributions have been reported at a number of energies in the range E_p = 5.00 to 44.3 MeV for the α₀ and α₁ groups: see (1975AJ02, 1980AJ01). See also (1981AU1D; astrophys.).

32. ¹⁴N(p, pt)¹¹C Q_m = -22.736

See (1978GO14, 1983GO10; theor.).

33. ¹⁴N(¹⁰B, ¹³C)¹¹C Q_m = 1.139

This reaction has been studied at E(¹⁰B) = 100 MeV: see (1980AJ01).

34. ¹⁶O(p, ⁶Li)¹¹C Q_m = -22.183

See (1975AJ02) and (1980HO14; theor.).

35. ¹⁶O(d, ⁷Li)¹¹C Q_m = -17.157

See (1984NE1A).