A=20Ne (1987AJ02)

Excitation functions have been measured for E(¹⁰B) = 6 to 30 MeV (reaction (a)) and 6 to 20 MeV (reaction (b)). Large resonant structures are observed in reaction (b), particularly at E_x ≈ 38 MeV (α₀) and 38.6 MeV (α to ¹⁶O*(7.0, 10.3, 16.2(u)), Γ ≈ 0.6 MeV. See also (1983KAZF) and (1978AJ03).

2. ¹⁰B(¹⁴N, α)²⁰Ne Q_m = 19.535

Angular distributions of α-particles to many states of ²⁰Ne below E_x = 10.7 MeV have been measured at E(¹⁴N) = 23.5 to 35 MeV. See also (1978AJ03, 1983AJ01).

3. ¹⁰B(¹⁶O, ⁶Li)²⁰Ne Q_m = 0.274

At E(¹⁶O) = 19.5 to 42 MeV angular distributions for the ⁶Li ions corresponding to transitions to ²⁰Ne*(0, 1.63, 4.25, 4.97, 5.62 + 5.79, 6.7 - 7.2) are in good agreement with Hauser-Feshbach calculations. See also (1978AJ03, 1985ST1B).

4. ¹¹B(¹⁶O, ⁷Li)²⁰Ne Q_m = -3.930

At E(¹¹B) = 115 MeV, angular distributions are reported to ²⁰Ne*(7.16, 8.78, 10.26, 11.95, 15.4). ²⁰Ne*(8.78, 15.4, 17.3, 21.0 ± 0.07, 22.78 ± 0.06) are particularly strongly populated. It is suggested that these five states have J^π = 6⁺, 7^-, (8⁺), 9^- and 9^-: see (1983AJ01).

5. ¹²C(⁹Be, n)²⁰Ne Q_m = 10.323

At E(⁹Be) = 16 and 24 MeV, angular distributions have been measured for ²⁰Ne*(7.3 ± 0.4, 9.2 ± 0.4, 10.9 ± 0.3, 12.2 ± 0.3, 15.7 ± 0.3): see (1983AJ01).

6. (a) ¹²C(¹⁰B, d)²⁰Ne Q_m = 5.961
(b) ¹²C(¹¹B, t)²⁰Ne Q_m = 0.764

At E(¹²C) = 45 MeV the population of states of ²⁰Ne with E_x = 8.45, 8.78, 9.03, 10.61, 10.67, 10.99, 11.01, 11.66, 11.94, 12.14, 12.39, 12.58, 12.73, 13.05, 13.17, 13.34 [7^-], 13.69, 13.91, 14.29, 14.36, 14.81, 15.17 [6⁺], 15.38 [7^-], 15.71 [(7, 8)], 15.89 [(7)], 16.16, 16.22, 16.51 [(8)], 16.73, 17.39 [9^-], 18.18 and 18.32 MeV is reported. [Values in brackets are J^π suggested on basis of Hauser-Feshbach calculations. The underlined states are well resolved: the authors indicate ± 20 keV for such states.] The relative intensities of the groups to ²⁰Ne*(17.39, 15.38) [J^π = 9^-, 7^-] argue against the existence of a superband: see (1978AJ03). See also (1983AJ01).

7. ¹²C(¹²C, α)²⁰Ne Q_m = 4.621

Double and triple (α, α, γ) correlations and γ-ray branching measurements [see Table 20.14 (in PDF or PS)] lead to the J^π assignments shown in Table 20.16 (in PDF or PS). See Table 20.15 (in PDF or PS) for assignments to rotational bands. Angular distributions have been reported at E(¹²C) = 4.9 to 51 MeV [see (1978AJ03, 1983AJ01)] and at 10.0 and 10.5 MeV (1982DA28; α₀), 11.38 to 13.23 MeV (1985BA43; α₀), 21 to 30 MeV (1984DH02, 1983FOZV; α₀), 29.5 to 30.5 MeV (1982KA17; many states) and 35.6 to 41.2 MeV (1984LE19; many states). At E(¹²C) = 38 to 64 MeV, ²⁰Ne*(7.17, 7.83, 8.54, 8.78, 9.03, 11.95, 12.13, 12.59, 13.90) are strongly populated and decay to ¹⁶O_g.s. (1987RA02). For γ-decay measurements see (1987FI01), Table 20.16 (in PDF or PS) and (1978AJ03).

The yields of various groups of α-particles and their relevance to states of ²⁴Mg, and fusion cross sections, have been studied by many groups: see (1978AJ03, 1983AJ01) for the earlier work and (1982DA28, 1982KA17, 1982SA27, 1983FOZV, 1984AR20, 1984DH02, 1984LE19, 1985BA43, 1986WU01).

See also (1982BLZT, 1983SH1Z, 1984HU1E, 1985XI1E, 1986TR08), (1981DA13, 1982CO1X, 1983SI1L, 1984CU1B), (1986SZ02; applied), (1982BA1D, 1982SA1A, 1984FO1A, 1985AR1A, 1986TH1E; astrophysics) and (1982HO05, 1982MO1V, 1982SU06, 1983AH1A, 1984DA1B, 1986FA12; theor.).

8. (a) ¹²C(¹⁴N, ⁶Li)²⁰Ne Q_m = -4.176
(b) ¹²C(¹⁴N, d)²⁴Mg → α + ²⁰Ne Q_m = -5.651

Angular distributions of the ⁶Li ions to many states of ²⁰Ne below 17.5 MeV have been reported for E(¹⁴N) = 30 to 78 MeV and E(¹²C) = 67.2 MeV. At the latter energy ²⁰Ne*(16.67, 17.38, 18.11, 19.16, 19.6) are particularly strongly populated: see (1978AJ03). For reaction (b) to ²⁰Ne_g.s. see (1984AR20, 1986WU01). See also (1982HO1E, 1985ST1B, 1986AR04) and ⁶Li in (1988AJ01).

9. ¹³C(⁹Be, 2n)²⁰Ne Q_m = 5.376

For cross sections see (1986CU02).

10. ¹⁴N(¹²C, ⁶Li)²⁰Ne Q_m = -4.176

See reaction 8.

11. ¹⁴N(¹⁴N, 2α)²⁰Ne Q_m = 7.923

For yields of 1.63 MeV γ-rays see (1982DE39).

12. ¹⁶O(α, γ)²⁰Ne Q_m = 4.734

Observed resonances in the yield of capture γ-rays over the range E_α = 0.8 to 10 MeV are displayed in Table 20.17 (in PDF or PS). For a discussion of ²⁰Ne*(11.28) [J^π = 1⁺; T = 1] whose excitation is parity forbidden see (1983FI02). See also (1984BU01). Total cross sections have been measured in the range E_c.m. = 1.7 to 2.35 MeV. Assuming that S does not vary with energy over that interval, the astrophysical factor for non-resonant capture to ²⁰Ne_g.s. is 0.26 ± 0.07 MeV · b. An estimate of 0.7 ± 0.3 MeV · b for S at 300 keV is deduced (1987HA24). See also Table 20.17 (in PDF or PS). For other papers on astrophysical considerations see (1982BA1D, 1982SA1A, 1984LA18, 1984NO1B, 1984TR1C, 1985AR1A, 1985TA1A, 1986DE27, 1986FI15, 1986KH1J). See also (1981KH1H, 1983BA50, 1983DE32, 1983LA25, 1984LA18, 1985BA2W, 1985BA1Q, 1986DE27; theor.).

13. ¹⁶O(α, d)¹⁸F Q_m = -16.3211 E_b = 4.734

See (1986KA36).

14. (a) ¹⁶O(α, α)¹⁶O E_b = 4.734
(b) ¹⁶O(α, 2α)¹²C Q_m = -7.16195

Excitation functions have been measured over a wide range of energies for elastically and inelastically scattered α-particles and γ-rays from the decay of ¹⁶O*(6.13, 6.92, 7.13) [see (1978AJ03, 1983AJ01)] and (1986LE23; 1.8 to 4.8 MeV; α₀), (1985JA17; 2.0 to 3.6 MeV; α₀), (1983CA1F, 1985CA09; 9.2 to 13.5 MeV; α₀), (1984LA1N, 1986LAZZ; 10.8 to 18 MeV; α₁; prelim.) and (1979BI10, 1984RI06; 14.6 to 20.4 MeV; α₀ → α₅). See also (1983FR14, 1985ISZU) and ¹⁶O in (1986AJ04).

A number of anomalies are observed: see Table 20.18 (in PDF or PS). K^π parameter assignments derived from this and other work are displayed in Table 20.15 (in PDF or PS) (1984RI07). See also (1983MI22). For reaction (b) see ¹²C in (1985AJ01). For cross sections of relevance to astrophysics for both reactions see (1985DY05; E_α = 10 to 26 MeV). For other channels see (1983AJ01). See also (1981BU27, 1983SA07, 1984BUZO, 1984SA28), (1984RE14), (1982WA1K, 1985ME1N; applications) and (1981SH1A, 1982AO06, 1982LE23, 1982SC16, 1983AO03, 1983BI1F, 1983BR1V, 1983CS02, 1983HO1D, 1983HO1F, 1983MA29, 1983MA68, 1983SM1B, 1983WA04, 1984BY02, 1984GO04, 1984OK04, 1984PR09, 1984SE20, 1984SU02, 1985MI11, 1985WA08, 1986ALZZ, 1986CEZW, 1986DE31, 1986HO33, 1986MA35, 1986SH07, 1986SU06, 1987HO1B, 1987PR01, 1987WA1B; theor.).

15. ¹⁶O(⁶Li, d)²⁰Ne Q_m = 3.259

Deuteron groups have been observed to many states of ²⁰Ne: see Table 20.19 (in PDF or PS). Angular distributions have been measured for E(⁶Li) = 5.5 to 75.4 MeV: see (1978AJ03, 1983AJ01). See also (1984MO08). Angular correlations [(d, α₀) to ¹⁶O_g.s.] have been measured at E(⁶Li) = 60, 75 and 95 MeV (1982AR20). See also (1986BE1D) and (1980GR1L, 1982ES1A, 1982GY02, 1983COZV, 1983OS03, 1983SU11, 1984GR29, 1986GR1R; theor.).

16. ¹⁶O(⁷Li, t)²⁰Ne Q_m = 2.266

States observed in this reaction are displayed in Table 20.19 (in PDF or PS). Angular distributions have been measured at E(⁷Li) = 15 to 68 MeV: see (1978AJ03, 1983AJ01). See also (1986CO15; theor.).

17. ¹⁶O(⁹Be, ⁵He)²⁰Ne Q_m = 2.27

See (1985CU1A).

18. (a) ¹⁶O(¹²C, ⁸Be)²⁰Ne Q_m = -2.633
(b) ¹⁶O(¹²C, 2α)²⁰Ne Q_m = -2.541
(c) ¹⁶O(¹²C, α¹²C)¹²C Q_m = -7.16195

Angular distributions in reaction (a) have been measured for E(¹⁶O) = 27.1 to 46.4 MeV and for E(¹²C) = 22.7 to 78 MeV [see (1978AJ03, 1985AJ01)] as well as at E(¹²C) = 109 MeV (1984MU04, 1985MU14; ²⁰Ne*(1.63, 4.25, 5.79, 7.16, 8.78, 10.26, 11.95, 12.59, 15.34, 15.87, 17.30, 21.08, 22.87); σ(θ) at several angles; EFR-DWBA analysis). Γ_α₀/Γ are displayed in Table 20.19 (in PDF or PS): see (1983AJ01) and (1983SH26). Preliminary evidence for 10⁺ strength at E_x ≈ 28 MeV is reported by (1986ALZN). See also (1983DEZW). For reaction (b) see (1978AJ03) and (1986CA19). For reaction (c) and for a discussion of ²⁴Mg states reached in this reaction see (1983SH26, 1984MU04). See also (1985BE37, 1987SU03) and (1986BE19; theor.).

19. ¹⁶O(¹³C, ⁹Be)²⁰Ne Q_m = -5.914

At E(¹³C) = 105 MeV angular distributions to ²⁰Ne*(1.63, 4.25, 8.78, 11.95, 15.34, 21.0) have been studied by (1979BR03): the first four states are the 2⁺, 4⁺, 6⁺ and 8⁺ members of the 0⁺₁ band; the two higher states [J^π = 7^-, 9^-] belong to the 0^- band whose band head is ²⁰Ne*(5.79). In addition distributions are reported to ²⁰Ne*(12.59, 15.9, 17.3) [J^π = 6⁺, 8⁺, 8⁺] (1979BR03). See also (1985MU14). For fusion cross sections see (1986PA10).

20. ¹⁶O(¹⁶O, ¹²C)²⁰Ne Q_m = -2.428

Angular distributions have been reported to a number of states of ²⁰Ne at E(¹⁶O) = 23.9 to 95.2 MeV [see (1978AJ03, 1983AJ01)] and recently at E(¹⁶O) = 26, 28 and 30 MeV (1986CA24). (1983ME13) have studied the quasi-elastic spectrum at E(¹⁶O) = 50, 60, 68 and 72 MeV. For excitation functions see (1986CA24; ²⁰Ne*(0, 1.63)). See also (1982KO1C, 1984ME10, 1985ST1B) and (1982KO1D, 1984AP03, 1984KO13; theor.).

21. (a) ¹⁷O(³He, ³He)¹⁷O E_b = 21.168
(b) ¹⁷O(³He, α)¹⁶O Q_m = 16.4341

The excitation function for α₀ shows a resonance corresponding to ²⁰Ne*(28.): see (1978AJ03). At E(pol. ³He) = 33 MeV A_y measurements have been reported for the elastic scattering [reaction (a)] (1983LE03) and for many α-groups [see ¹⁶O in (1986AJ04)] (1982KA12). For the earlier work and for other channels see (1983AJ01). See also (1985HA11, 1987CO07; theor.).

22. ¹⁷O(α, n)²⁰Ne Q_m = 0.590

See (1978AJ03).

23. (a) ¹⁷O(¹¹B, ⁸Li)²⁰Ne Q_m = -6.041
(b) ¹⁷O(¹²C, ⁹Be)²⁰Ne Q_m = -5.111

At E = 115 MeV the 8⁺ state at E_x = 11.95 MeV is particularly strongly populated in both reactions: see (1983AJ01).

24. ¹⁸O(³He, n)²⁰Ne Q_m = 13.124

Angular distributions have been measured for E(³He) = 2.8 to 18.3 MeV. States of ²⁰Ne observed in this reaction are displayed in Table 20.23 (in PDF or PS) of (1983AJ01). These include a state at E_x = 16.730 ± 0.006 MeV, Γ < 20 keV: J^π = 0⁺, T = 2.

25. ¹⁹F(p, γ)²⁰Ne Q_m = 12.848

Over the range E_p = 2.9 to 12.8 MeV, the γ₀ and γ₁ yields are dominated by the E1 giant resonance (Γ ≈ 6 MeV) with the γ₁ giant resonance displaced upward in energy. Strong well-correlated structure is observed with a characteristic Γ ≈ 175 keV. Angular distributions taken over the energy range do not vary greatly with energy. They are incompatible with γ₀ and γ₁ coming from the same levels in ²⁰Ne. The 90° γ₀ yield for E_{pol. p} and E_p = 3.5 to 10 MeV has been measured: the results are interpreted in terms of four primary doorway states at E_x = 16.7, 17.8, 19.1 and 20.2 MeV. See also (1985WAZV; E_pol. p = 5.9 to 10.3 MeV; E2 strength; prelim.). See also (1986OUZZ).

The yield curve for 11.2 MeV γ-rays [from the decay of ²⁰Ne*(11.23), J^π = 1⁺, T = 1, to the ground state] displays a resonance at E_p = 4.090 ± 0.005 MeV [²⁰Ne*(16.73)]. The 11.2 MeV γ-rays are isotropic which is consistent with the presumed 0⁺ character of this lowest T = 2 state in ²⁰Ne: Γ_pΓ_γ/Γ ≈ 0.5 eV. Since Γ_p/Γ (from the elastic scattering) is ≈ 0.1, Γ_γ ≈ 5 eV. For E_p = 5.65 to 6.21 MeV, the γ₀ and γ₁ yields are not resonant but the yield of 10.6 MeV γ-rays is resonant at 5.879 ± 0.007 MeV [Γ_c.m. = 9.5 ± 3 keV, Γ_p₀Γ_γ/Γ ≈ 0.05 eV; Γ_γ ≈ 0.3 eV]. The 10.6 MeV γ-ray is due to the cascade decay of ²⁰Ne*(18.43), J^π = 2⁺; T = 2 via ²⁰Ne*(12.22) to the 2⁺ state at 1.63 MeV. For the upper limits to the strengths of the transitions to various states of ²⁰Ne from the 0⁺ and 2⁺ T = 2 states, see (1983AJ01). Resonances observed in this capture reaction are displayed in Table 20.20 (in PDF or PS). For references see (1978AJ03, 1983AJ01). See also (1987RO25; astrophysics).

26. (a) ¹⁹F(p, p)¹⁹F E_b = 12.848
(b) ¹⁹F(p, p')¹⁹F*
(c) ¹⁹F(p, d)¹⁸F Q_m = -8.2074

The elastic scattering has been studied in the range E_p = 0.5 to 7.5 MeV and 24.9 to 46.3 MeV [see (1978AJ03)] and at E_p = 1.5 to 3.5 MeV (1985OU01, 1986OUZZ, 1986OU01). The observed anomalies are displayed in Table 20.21 (in PDF or PS).

Resonances for inelastic scattering [p₁ and p₂] are listed in Table 20.22 (in PDF or PS). In general the resonances observed are identical with those reported from other ¹⁹F + p reactions, although the relative intensities differ greatly. Cross sections for production of 110 and 197 keV γ-rays are reported for E_p = 0.5 to 4.3 MeV by (1986CHYY). See also (1983LE28; astrophysics) and (1986BA88). For reaction (c) see (1986KA1U; applied) and ¹⁸F.

27. ¹⁹F(p, n)¹⁹Ne Q_m = -4.0207 E_b = 12.848

Observed resonances are displayed in Table 20.30 (in PDF or PS) of (1978AJ03). See also (1984BA1R).

28. ¹⁹F(p, α)¹⁶O Q_m = 8.1137 E_b = 12.848

Many resonances occur in this reaction. They are displayed in Tables 20.23 (in PDF or PS), 20.24 (in PDF or PS) and 20.25 (in PDF or PS) depending on whether they are observed in the α₀ yield [Table 20.23 (in PDF or PS)], in the α₁ [or α_π] yield to ¹⁶O*(6.05) [Table 20.24 (in PDF or PS)] or in the α₂, α₃ and α₄ yields [or in the yield of the γ-rays from ¹⁶O*(6.13, 6.92, 7.12) [Table 20.25 (in PDF or PS)]]. Resonances for α₀ and α₁ are required to have even J, even π or odd J, odd π, while the α₂, α₃ and α₄ resonances are all odd-even or even-odd, with the exception of the T = 2 resonance.

Listings of the earlier yield studies are given in (1972AJ02, 1978AJ03, 1983AJ01). A detailed discussion of the evidence leading to many of the J^π assignments is given in (1959AJ76). For values of θ² see Table 20.28 (in PDF or PS) in (1978AJ03). Recent measurements are reported by (1985OU01; 1.15 to 2.1 MeV; α₀ → α₃) and (1984IN04; 4.15 to 13 MeV; α₀ → α₅). In the latter work there are no marked correlations between the different channels.

Longitudinally and transversely polarized protons with E_{pol. p} ≈ 0.67 MeV have been used to study ²⁰Ne*(13.48) [J^π = 1⁺; T = 1] via a parity (and isospin) forbidden α-transition. The state is not excited. The upper limits for the process, and their significance in the determination of f_π, the weak pion-nucleon coupling constant, are discussed by (1983KN01, 1986KN1C). See also (1983AJ01, 1984KN1A).

See also (1985ISZU), (1982MA1Q, 1982MA1V, 1983DE2J, 1986SI1L; applications), (1987RO25; astrophysics), (1986SI1D; computing) and (1983IN1B, 1985LO1C, 1986LO1E, 1986SI1K; theor.).

29. ¹⁹F(d, n)²⁰Ne Q_m = 10.623

Levels of ²⁰Ne derived from this reaction are displayed in Tables 20.31 (in PDF or PS) in (1972AJ02) and 20.34 (in PDF or PS) in (1978AJ03). See also (1983LIZW).

30. ¹⁹F(³He, d)²⁰Ne Q_m = 7.354

Levels of ²⁰Ne observed in this reaction are displayed in Table 20.35 (in PDF or PS) of (1978AJ03). Deuteron angular distributions have been studied at E(³He) = 9.5 to 21 MeV: see (1978AJ03).

The ΔE_x between the 1⁺ and 1^-, T = 1 states ²⁰Ne*(11.26, 11.27) is 11.1 ± 0.7 keV (1983FI02). Γ_γ/Γ_α = 0.88 ± 0.05 for ²⁰Ne*(12.22) [2⁺; T = 1] (1984CA08). Using (2J + 1) Γ_αΓ_γ/Γ = 1.41 ± 0.23 eV (1980FI01), Γ_α = 0.32 ± 0.06 eV for ²⁰Ne*(12.22) (1984CA08). The Γ_γ/Γ of ²⁰Ne*(12.22) implies B(M1) = 0.07 W.u. for the transition from ²⁰Ne*(18.43) [2⁺; T = 2]. This is much weaker than other isovector M1 transitions in ²⁰Ne and a factor of five lower than predicted by shell model calculations: see (1984CA08).

31. ¹⁹F(α, t)²⁰Ne Q_m = -6.966

Angular distributions have been measured at E_α = 18.5 and 28.5 MeV: see (1978AJ03, 1983AJ01).

32. ¹⁹F(⁷Li, ⁶He)²⁰Ne Q_m = 2.873

Angular distributions have been studied at E(⁷Li) = 34 MeV to a number of states of ²⁰Ne. C²S values are consistent with those reported in the (d, n) and (³He, d) reactions: see (1978AJ03).

33. ²⁰F(β^-)²⁰Ne Q_m = 7.029

The decay is primarily to ²⁰Ne*(1.63) with a half-life of 11.00 ± 0.02 sec: see reaction 1 in ²⁰F. Besides the principal decay to ²⁰Ne*(1.63) [log f₀t = 4.97], ²⁰F also decays to ²⁰Ne*(4.97) [J^π = 2^-] with a branching ratio of (0.0082 ± 0.0006)% (1987AL06) [log f₀t = 7.20 ± 0.03; D.E. Alburger and E.K. Warburton, private communication]. The upper limit for the ground-state decay is 0.001% [log f₀t > 10.5]. For other values and earlier references see Table 20.36 (in PDF or PS) in (1978AJ03). The energy of the γ-ray from ²⁰Ne*(1.63) is 1633.602 ± 0.015 keV. E_γ for the 4.97 → 1.63 transition is 3332.54 (19) keV which gives E_x = 4966.51 (20) keV based on E_x = 1633.674 (15) keV for the first excited state. The shape of the β-spectrum is not inconsistent with the predictions of CVC. β-γ correlation measurements lead to an upper limit for the second-class current contribution to the correlation which is consistent with zero. For references see (1983AJ01); for the earlier work see (1978AJ03). See also (1985BR29, 1985GR1A) and (1983KA32, 1985YA1J; theor.).

34. (a) ²⁰Ne(γ, n)¹⁹Ne Q_m = -16.869
(b) ²⁰Ne(γ, 2n)¹⁸Ne Q_m = -28.508
(c) ²⁰Ne(γ, α)¹⁶O Q_m = -4.734

The photoneutron cross section (bremsstrahlung photons) shows peaks at E_x = 17.78 ± 0.05, 19.00 ± 0.05, 20.15 ± 0.15 [main peak of the GDR], 22.6 ± 0.3, 24.9 ± 0.5 and 27.5 MeV [the latter three states are broad]: the integrated cross section to 28.5 MeV is 58 ± 6 MeV · mb [exhausting ≈ 20% of the dipole sum]. The cross section for (γ, Tn) using monoenergetic photons shows a structure at 18 MeV and some fluctuations atop the broad giant resonance, σ_max ≈ 7 mb. The double photo-neutron cross section, σ(γ, 2n), is dominated by a single peak at ≈ 20.5 MeV, σ_max ≈ 1.1 mb. For references see (1978AJ03, 1983AJ01). The significance of reaction (c) to astrophysics is discussed by (1982SA1A, 1984FO1A).

35. ²⁰Ne(γ, γ)²⁰Ne

E_x = 11262.3 ± 1.9 keV for ²⁰Ne*(11.26), the first 1⁺; T = 1 state. The branchings to ²⁰Ne*(0, 1.63) are (84 ± 5) and (16 ± 5)%, respectively (1983BE19). See also (1984BE26).

36. (a) ²⁰Ne(e, e)²⁰Ne
(b) ²⁰Ne(e, ep)¹⁹F Q_m = -12.848
(c) ²⁰Ne(e, eα)¹⁶O Q_m = -4.734

The ²⁰Ne charge radius, < r² > ^1/2 = 3.004 ± 0.025 fm. Form factors for many excited states of ²⁰Ne with E_x < 8 MeV have been reported: see (1978AJ03).

At E_e = 39 and 56 MeV, the 180° inelastic scattering is dominated by the transition to a J^π = 1⁺, T = 1 state at E_x = 11.22 ± 0.05 MeV with Γ_γ₀ = 11.2⁺2.1_-1.8 eV. A subsidiary peak is observed corresponding to a state 0.35 ± 0.03 MeV higher [if J^π = 1⁺ or 2⁺, Γ_γ₀ = 0.65 ± 0.18 or 0.40 ± 0.13 eV]. A number of small peaks are also reported corresponding to E_x ≈ 12.0, 12.9, 13.9, 15.8, 16.9, 18.0 and 19.0 MeV. Prominent electric dipole peaks are reported at E_x = 17.7, 19.1, 20.2 and 23 MeV, in addition to weaker structures between 12.5 and 15 MeV; and prominent electric-quadrupole peaks are observed at E_x = 13.0, 13.7, 14.5, 15.0, 15.4 and 16.2 MeV and there is a broad quadrupole excitation between 16 and 25 MeV. The GDR cross scetion integrated from 11 to 25 MeV contains about 65% of the dipole EWSR while over 90% of the isoscalar quadrupole EWSR is exhausted by the strength in the region 10 - 25 MeV.

For 11 < E_x < 24 MeV only two isovector M2 transitions appear: These are to ²⁰Ne*(11.62, 12.10) with B(M2, k)(↑) = 64 ± 13 and 56 ± 13 μ²_N fm² [orbital contributions are non-negligible]. The M1 transition to ²⁰Ne*(11.26) is also observed but that to ²⁰Ne*(13.48) is not: it is < 0.2 μ²_N (1985RA08). For reaction (b) see (1978AJ03).

Reaction (c) has been studied in order to obtain the (γ, α₀) cross section in the giant resonance region: the cross section at 90° for E_x = 15 to 24 MeV is dominated by an E1 resonance [1^-; T = 1, with an admixture of T = 0 which permits the α₀ decay] at E_x = 20 MeV; lesser E1 structures are reported at E_x = 16.7, 17.1, 21 and 22 MeV. A relatively strong 2⁺; T = 0 resonance appears at E_x = 18.5 MeV, and evidence is reported for increasing E2 strength below 16 MeV. For references see (1978AJ03). See also (1987DE43) and (1978WI1B, 1982RU05, 1983BR1P, 1983KN05, 1984AM03, 1984AM07, 1985LE1H, 1985LE14, 1985ST23, 1986BR1X, 1986KA17, 1986SH16, 1986TA1W, 1986VA12, 1987VA12; theor.).

37. ²⁰Ne(n, n)²⁰Ne

See (1978AJ03).

38. (a) ²⁰Ne(p, p)²⁰Ne
(b) ²⁰Ne(p, pα)¹⁶O Q_m = -4.734

Angular distributions of elastically scattered protons and of a number of inelastic groups have been measured for E_p = 2.15 to 65 MeV [see (1978AJ03, 1983AJ01)] and at E_pol. p = 0.8 GeV (1984BL14; to ²⁰Ne*(0, 1.63, 4.25, 8.7(u); also A_y). The latter work confirms the large hexadecapole deformation of ²⁰Ne. At E_p = 201 MeV, probable 1⁺ states at E_x = 11.25 ± 0.01, 13.51 ± 0.03 and 15.72 ± 0.05 MeV are reported by (1987WI03): There does not appear to be any quenching of the M1 strength. In addition 2^- states are observed at 11.58 and 12.08 MeV with B(M2) = 64 ± 13 and 56 ± 13 μ²_N as is a state of unknown J^π at E_x ≈ 17 MeV (1987WI03). See also the earlier work in (1978AJ03). For reaction (b) see (1984CA09; E_p = 101.5 MeV). See also (1983CE1A, 1986BA2U), (1986BA88) and (1982SC20, 1983SM04, 1984AM03, 1984AM07, 1985KN04; theor.).

39. ²⁰Ne(p-bar, p-bar)²⁰Ne

For a study of antiproton interactions see (1986BA22).

40. (a) ²⁰Ne(d, d)²⁰Ne
(b) ²⁰Ne(t, t)²⁰Ne

Angular distributions of deuterons have been reported at E_d = 10.0 to 52 MeV [see (1978AJ03, 1983AJ01)] and at E_pol. d = 52 MeV (1987NU01). For reaction (b) see (1978AJ03).

41. ²⁰Ne(³He, ³He)²⁰Ne

Angular distributions have been measured at E(³He) = 10 to 35 MeV and at 68 MeV: see (1978AJ03). See also (1987TR01; theor.).

42. (a) ²⁰Ne(α, α)²⁰Ne
(b) ²⁰Ne(α, 2α)¹⁶O Q_m = -4.734

Angular distributions have been measured at E_α = 3.8 to 155 MeV [see (1978AJ03, 1983AJ01)] and at 54.1 MeV (1987AB03; g.s.). See also (1986BU1L; E_α = 50.5 MeV). For a spallation study see (1984AN1H); for cross sections of astrophysical interest see (1984SE02). For reaction (b) see (1983AJ01). See also (1984SA28, 1986TR08), (1982VO04, 1983CH1B) and (1982JA07, 1982WA13, 1984BU1R, 1984SR01, 1985UM01, 1986GA1N, 1986KA17; theor.).

43. ²⁰Ne(⁷Li, ⁷Li)²⁰Ne

Angular distributions have been studied at E(⁷Li) = 36, 68 and 89 MeV: see (1983AJ01).

44. ²⁰Ne(⁹Be, ⁹Be)²⁰Ne

For pion production see (1985FR13).

45. (a) ²⁰Ne(¹⁰B, ¹⁰B)²⁰Ne
(b) ²⁰Ne(¹¹B, ¹¹B)²⁰Ne

Elastic angular distributions have been measured at E(¹⁰B) = 65.9 and E(¹¹B) = 115 MeV: see (1983AJ01).

46. (a) ²⁰Ne(¹²C, ¹²C)²⁰Ne
(b) ²⁰Ne(¹²C, α⁸Be)²⁰Ne Q_m = -7.3665

Elastic angular distributions have been obtained at E(¹²C) = 22.2 to 42.7 MeV and 77.4 MeV and at E(²⁰Ne) = 65.9, 74 and 75.2 MeV [see (1978AJ03, 1983AJ01)] as well as at E(²⁰Ne) = 72.6, 74.0 and 75.2 MeV (1982SH29). For yield, fusion, total reaction cross section and fragmentation studies see (1982KO29, 1982MO15, 1982SH29, 1984AN1H, 1984KO12, 1985FL1B, 1985OS05, 1986BL1K, 1987KO12) and (1983AJ01). For pion production see (1982AN1H, 1983AN1L). For reaction (b) see (1983AJ01), (1984RA10, 1987SI06) and ¹²C in (1985AJ01). See also (1985MU18), (1983HE1B, 1984FR1A, 1984HA53, 1984NA1D, 1984ST1B, 1985BE1A, 1985CU1A, 1985ST1B, 1986IK03, 1986ST1J, 1987LA05, 1987SC1D) and (1982LO13, 1983CI08, 1983TO1L, 1984HA43, 1984IN03, 1984MAZT, 1984SH1T, 1985CH11, 1985GA1G, 1985GU1J, 1985HU04, 1985KO1J, 1986GA1F, 1986GI03, 1986HA13, 1986HE1A; theor.).

47. ²⁰Ne(¹⁶O, ¹⁶O)²⁰Ne

Angular distributions have been studied at E(²⁰Ne) = 50 and 94.8 MeV involving ¹⁶O_g.s. and ²⁰Ne*(0, 1.63, 4.25) [see (1983AJ01)], at E(¹⁶O) = 25.6 to 44.5 MeV (1984GA22; elastic; also to ²⁰Ne*(1.63) at 31.3, 33.3 and 44.5 MeV)) and at E(²⁰Ne) = 66.8, 115, 137 and 156 MeV (1983SH25; elastic). Yield and fusion cross section measurements are reported by (1982SC13, 1982SH1N, 1983BR1R, 1983SH25, 1984GA22) and in (1983AJ01). See also (1983DU13, 1986BA69, 1986ST1J, 1987SC1D) and (1983KO31, 1983MA29, 1984NI1D, 1985CH11, 1985GU1J, 1985IC01, 1985KO43, 1985KO38, 1986GA1F, 1986HE1A, 1986KO1C, 1986TA1A; theor.).

48. ²⁰Ne(²⁰Ne, ²⁰Ne)²⁰Ne

Elastic angular distributions are reported at E(²⁰Ne) = 68, 117, 140 and 156 MeV (1983SH25). For yield and fusion measurements see (1983PO09, 1983SH25) and (1983AJ01). See also (1983RA1J, 1987SC1D) and (1983AB1G, 1983GO13, 1983SI01, 1984TO02, 1985GA1T, 1985IV1C, 1985IV1B, 1987BA1V; theor.).

49. (a) ²⁰Ne(²⁴Mg, ²⁴Mg)²⁰Ne
(b) ²⁰Ne(²⁶Mg, ²⁶Mg)²⁰Ne

Elastic angular distributions for reaction (a) have been measured at E(²⁰Ne) = 50, 60, 80, 90 and 100 MeV [see (1983AJ01)] and at 40 MeV (1983NA04; S_α for the system ²⁰Ne + ²⁴Mg = 0.08 ± 0.02). For yield and fusion cross sections see (1982GR1T, 1983AL01, 1984CHZU [also reaction (b)], 1984LE06) and (1983AJ01). See also (1983BI13, 1983DU13, 1984FR1A, 1986BL08) and (1982LO13, 1983OH1C, 1985NI1C, 1987BA01; theor.).

50. ²⁰Ne(²⁷Al, ²⁷Al)²⁰Ne

Elastic angular distributions are reported at E(²⁰Ne) = 55.7, 63, 125 and 151 MeV (1983NG01). For yield, fusion and evaporation residue studies see (1982MO15, 1983MO13, 1983NG01, 1985MO08, 1986GRZK, 1987JA06) and (1983AJ01). See also (1983BI13, 1983HE1B, 1984FR1A, 1984HA53, 1985ST1B, 1985TU01) and (1982LO13, 1983CI08, 1983GO13, 1983OH1B, 1984BI06, 1985HU04; theor.).

51. (a) ²⁰Ne(²⁸Si, ²⁸Si)²⁰Ne
(b) ²⁰Ne(²⁹Si, ²⁹Si)²⁰Ne

See (1983DU13).

52. ²⁰Ne(⁴⁰Ca, ⁴⁰Ca)²⁰Ne

Angular distributions have been studied at E(²⁰Ne) = 44.1 to 70.4 MeV and at 151 MeV: see (1983AJ01). For an evaporation residue study see (1982MO15). For yield and fusion measurements see (1983AJ01). The breakup of ²⁰Ne at E(²⁰Ne) = 92, 149 and 213 MeV involves ²⁰Ne*(5.79, 6.73, 7.16, 8.78, 10.26, 11.95) (1986SH30). See also (1983BI13, 1983HE1B, 1984FR1A) and (1982ST08, 1983SI01, 1984GU09, 1984SH2D, 1985AN16, 1985GU08; theor.).

53. ²⁰Na(β⁺)²⁰Ne Q_m = 13.887

²⁰Na has a half-life of 447.9 ± 2.3 msec: see reaction 1 in ²⁰Na. It decays to a number of states of ²⁰Ne, principally ²⁰Ne*(1.63): see Table 20.26 (in PDF or PS). The ratio of the mirror decays ²⁰Na β⁺/→ ²⁰Ne*(1.63) and ²⁰F β^-/→ ²⁰Ne*(1.63), (ft)⁺/(ft)^- = 1.03 ± 0.02. β-γ correlation measurements, as in the decay of ²⁰F, lead to an upper limit for the second-class contribution to the correlation which is consistent with zero: see (1983AJ01). β-ν-α triple correlation coefficient measurements for the transitions via the α-unstable 2⁺ states shown in Table 20.26 (in PDF or PS) lead to values of the isospin mixing amplitudes [and to a determination of the vector weak coupling constant] (1983CL01). See also (1987ROZZ) and (1983HA1V, 1985BR29, 1985GR1A, 1985HA1T).

54. ²¹Ne(p, d)²⁰Ne Q_m = -4.536

See (1978AJ03).

55. ²¹Ne(d, t)²⁰Ne Q_m = -0.503

The T = 1 states observed in this reaction, and ther analog states observed in ²⁰F in the (d, ³He) reaction, are displayed in Table 20.16 (in PDF or PS) of (1978AJ03). T = 0 states are presented in Table 20.38 (in PDF or PS) of (1978AJ03).

56. ²²Ne(p, t)²⁰Ne Q_m = -8.641

Angular distributions have been reported at E_p = 26.9 to 43.7 MeV: see (1978AJ03, 1983AJ01). The angular distributions of the tritons to the ground state of ²⁰Ne and to the first 0⁺, T = 2 state [E_x = 16.722 ± 0.025 MeV] have been fitted by L = 0 and the tritons to ²⁰Ne*(18.4) by L = 2. The latter is the first 2⁺, T = 2 state. The 0⁺, T = 2 state [²⁰Ne*(16.73)] decays by α₀[(-6 ± 5)%], α₁ + α₂[(35 ± 12)%], α₃ + α₄[(29 ± 12)%], p₀ + p₁ + p₂[(14 ± 9)%] and p₃ + p₄ + p₅[(13 ± 8)%] [measured branching ratios in percent are given in the brackets] to final states in ¹⁶O and ¹⁹F. See (1978AJ03) for references and additional information.

57. ²³Na(p, α)²⁰Ne Q_m = 2.379

Angular distributions have been measured at E_p = 10.0 and 45.5 MeV: see (1972AJ02). For astrophysical considerations see (1982SA1A, 1984FO1A, 1985AR1A) and (1983AJ01). See also (1985RH1A) and (1986TU1B; applied).

58. ²³Na(³He, ⁶Li)²⁰Ne Q_m = -1.639

See (1978AJ03).

59. ²⁴Mg(p, pα)²⁰Ne Q_m = -9.312

See (1984CA09). See also (1978AJ03).

60. ²⁴Mg(d, ⁶Li)²⁰Ne Q_m = -7.837

Angular distributions have been studied to many states of ²⁰Ne at E_d = 28 to 80 MeV [see (1978AJ03, 1983AJ01)] and at E_d = 54.2 MeV (1984UM04; to ²⁰Ne*(0, 1.63, 4.25, 5.62)). Table 20.35 (in PDF or PS) in (1983AJ01) displays the observed states and S_α obtained from several analyses. For newer values of S_α see (1984UM04, 1986OE01). See also (1984PA18, 1986PAZJ; theor.).

61. ²⁴Mg(³He, ⁷Be)²⁰Ne Q_m = -7.724

Angular distributions have been studied at E(³He) = 25.5 and 70 MeV: see (1978AJ03). See also (1983AJ01) and (1986RA15; theor.).

62. ²⁴Mg(α, ⁸Be)²⁰Ne Q_m = -9.404

See (1983AJ01).

63. ²⁴Mg(¹²C, ¹⁶O)²⁰Ne Q_m = -2.150

The angular distribution for the ground state transition has been measured at E(¹²C) = 40 MeV (1982LI16). See also (1983AJ01).

64. ²⁸Si(α, ¹²C)²⁰Ne Q_m = -12.021

See (1983AJ01).