(See Energy Level Diagrams for 10B)
GENERAL: See (1959BA1F, 1959BR1E, 1960TA1C, 1961TR1B, 1962IN02, 1963BU1C, 1963KU03, 1963ME01, 1963MO1F, 1963OL1B, 1963VL1A, 1963WA1M, 1964AM1D, 1964BA29, 1964FR1D, 1964GR1J, 1964MA1G, 1964NE1E, 1964OL1A, 1964ST1B, 1964VA1D, 1965FA1C, 1965NE1C). See also Table 10.6 [Table of Energy Levels] (in PDF or PS).
Six resonances are observed in the range Eα = 0.5 to 2.6 MeV, corresponding to 10B*(4.76 - 6.06 MeV): see Table 10.8 (in PDF or PS). No other resonances appear for Eα < 3.8 MeV (10B*(6.74)) (1957ME27, 1961SP02).
The 4.77 MeV state decays mainly to 10B*(0.7): the ground state decay is < 3% (1957WA07), 8% (1957ME27): see also Table 10.7 (in PDF or PS). The angular distribution of γ-rays indicates J = 2+, with E2/M1 = 1.8 (1957ME27), 0.64 (1957WA07). The measured ωΓs ≡ ωΓγΓα/(Γγ + Γα) is 0.05 eV: Γ(M1) ≈ 0.01 ΓW, Γ(E2) ≳ 10 ΓW, consistent with the ΔT selection rule for M1 and considerable collective enhancement for E2 (1957ME27, 1957WA07, 1958ME81, 1963WA17).
The angular distribution of the γ-rays from the 5.11-MeV state can be made consistent with J = 2-; T = 0 if M2/E1 ≈ 0.01 is assumed (1957ME27, 1958ME81). The distributions from Ex = 5.17 MeV are consistent with Jπ = 2+ (1957ME27): observations in 9Be(d, n)10B indicate Γα ≈ Γγ = 1.3 eV and hence T = 1 (1958ME81, 1959WA16, 1962WA21).
A study of α-capture near Eα = 1.18 MeV shows the formation of a broad J = 1; T = 0 state (Ex = 5.18 MeV, Γc.m. = 200 ± 30 keV), and its subsequent decay via 3.44 MeV γ-rays to the Jπ = 0+; T = 1 state at 1.74 MeV. The observed width corresponds to 0.86 of the single particle limit for s-wave α-formation (1961SP02: see, however, (1962DE10)). See also (1962WA21).
For the 5.92 MeV level, Jπ = 2±, 3+, and 4+ are possible. Only Jπ = 4+ gives a satisfactory account of the angular distribution from the 6.03 MeV level (1957ME27).
Reported anomalies in the elastic scattering are listed in Table 10.9 (in PDF or PS) (1962BA03, 1962DE10, 1965SI1B). Angular distributions indicate Jπ = 1+ and 2+, respectively for the 5.18 and 5.92 MeV states. The 1+ assignment supports the proposal by (1961TR1B) that the 5.18 MeV state is a member of the doublet formed by two-nucleon excitation into the 2s shell, whose other member is the 0+; T = 1 state at 7.56 MeV.
The excitation functions for α0 and α1 (to the 2.18 MeV state of 6Li) particles (1963BL20: Eα = 9.50 to 12.50 MeV), d0 particles (to the ground state of 8Be) (1963BL20: Eα = 9.50 to 11.4 MeV) and neutrons (1963ME08: from threshold, Eα = 6.623 MeV, to 15.5 MeV) do not show resonance structure. See also (1956WA29, 1964DE1K).
Reactions (a) and (b) have been studied up to 6 MeV bombarding energy. Deuteron and triton groups have been observed leading to the first four states of 10B with intensities which depend on the incident energy: typically the group to the 0.7 MeV state is very strong and that to the 1.74 MeV state is very weak (1960MO17, 1961BR35, 1961MO02, 1964KI02). See also (1962BE24, 1962BU1C, 1962MC12, 1963LE09, 1964BL1C). For reaction (c) see (1962MC12, 1963NO02).
The excitation curve for reaction (a) is smooth up to E(3He) = 1.8 MeV (1962SE1A, 1963DU12), and shows resonance behavior at E(3He) = 2.2 and 3.25 MeV: the 2.2 MeV resonance has Γ ≈ 280 keV; the 3 MeV resonance is broader (1963DI01, 1963DU12, 1964DI1C).
Capture γ-rays have been observed for E(3He) = 0.8 to 3.0 MeV. The excitation functions for the transitions to the ground and 4.77 MeV states show peaks at E(3He) = 1.1 and 2.2 MeV; those to the 0.72 and 3.59 MeV states show a broad maximum at 1.4 MeV. The observed gamma widths are comparatively large (see Table 10.10 (in PDF or PS)) (1965PA02).
The yield of protons (reaction (b)) is relatively flat for E(3He) = 2.5 to 4.8 MeV, with some indication of a weak maximum at ≈ 3.3 MeV at 20° and 50° (1961WO05). The yield of ground state α-particles at 8° (reaction (d)) shows a broad maximum at ≈ 2 MeV, a minimum at 3 MeV, followed by a steep rise which flattens off between E(3He) = 4.5 and 5.5 MeV. Integrated α0 and α1 yields rise monotonically to 4 MeV and then tend to decrease. Angular distributions of α1 in the range E(3He) = 2 to 5.5 MeV suggest that the reaction proceeds mainly by pickup (1965FO07: se also (1961WO05)). Angular distributions for E(3He) = 0.8 to 3.0 MeV give indications of the resonances at E(3He) = 1.4 and 2.2 MeV seen in 7Li(3He, γ): Jπ = 2+ or 1-; T = (1) for both: Γα is small (1965PA03).
Observed slow neutron thresholds are listed in Table 10.11 (in PDF or PS) (1957BI84, 1963ME08). At Eα = 13.5 and 13.9 MeV, angular distributions of the ground-state neutrons have been determined (1962KJ05). See also (1959HE1B, 1962GA1L).
The Ep = 0.33 MeV resonance (10B*(6.88)) is ascribed to s-wave protons because of its comparatively large proton width [see 9Be(p, p)] and because of the isotropy of the γ-radiation. The strong transition to 10B*(1.74) requires E1 and hence Jπ = 1-; T = 0. T = 0 is also indicated by the large deuteron width. On the other hand, the strength of E1 transitions to 10B*(0.7, 2.1) indicate a T = 1 admixture of 20% or more (1956WI16, 1959ME85). A small P2 term in the angular distribution at resonance suggests a d-wave admixture. The angular correlation of 6.88 → 0.72 → g.s. is consistent with Jπ = 1- but does not exclude 2- (1964BI18).
The proton capture data near Ep = 1 MeV appears to require at least 5 resonant states, at Ep = 938, (980), 992, 1086 and 1290 keV. The narrow Ep = 1086 keV level (10B*(7.56)) is formed by p-wave protons, Jπ = 0+ [see 9Be(p, p) and 9Be(p, α)]. The isotropy of the gamma rays supports this assignment (1961TA02). The strong M1 transitions to J = 1+; T = 0 levels at 0.7, 2.15 and 5.18 MeV (Table 10.13 (in PDF or PS)) indicate T = 1 (1959WA16).
The excitation function for ground-state radiation shows resonance at Ep = 992 (Γ = 80 keV) and 1290 keV (Γ = 230 keV) (1962EL06, 1964HO02). Elastic scattering studies indicate s-wave formation and J = 2- for both (1956MO90). For the lower level (Ex = 7.48 MeV) the intensity of the g.s. capture radiation, Γγ = 25 eV (1964HO02) indicates E1 and T = 1. The angular distribution of γ-rays, 1 + 0.1 sin2 θ, is consistent with s-wave formation with some d-wave admixture (1953PA22) or with some contribution from a nearby p-wave resonance (1956MO90); possibly a Jπ = 2+ level at Ep = 980 keV (1956MO90, 1962EL06: see, however, (1964HO02)). The angular correlation of internal pairs is consistent with an E1/M1 mixture of 3 : 2 (1962EL06). Earlier difficulties with the T = 1 assignment may be resolved if the (p, d) and (p, α) resonances are ascribed to another level (1964HO02).
Transitions to 10B*(0.7) show resonance at Ep = 992, 1290 and 938 keV, Γ = 155 keV (1962EL06, 1964HO02). The latter is presumably also a resonance for (p, d) and (p, α). An assignment of Jπ = 2-: T = 0 is consistent with the data, although the E1 radiation then seems somewhat too strong for a ΔT = 0 transition (1964HO02).
A resonance for capture radiation at Ep = 2.567 ± 0.003 (Ex = 8.896 MeV) has a width of 40 ± 2 keV and decays mainly via 10B*(0.7) (1953MA1A). It appears from the width that this resonance corresponds to that observed in 9Be(p, α), J = 2+; T = 1 and not to the 9Be(p, n) resonance at the same energy (1956MA55). A fourth resonance is reported at Ep = 4.72 ± 0.01 MeV, Γ ≈ 0.5 MeV (1952HA10).
Resonances in neutron yield occur at Ep = 2.56 and 4.6 MeV: see Table 10.14 (in PDF or PS). There is some indication of a broad maximum near Ep = 3.5 MeV; a peak reported at Ep = 4.9 MeV for n1 neutrons may reflect the effect of this level (1959MA20). A sharp break at Ep = 6.55 ± 0.03 MeV is ascribed to a level in 9B at 4.04 MeV (1964BA16). Angular distributions in the range Ep = 2 to 11 MeV are reported by (1956MA55, 1961AL07, 1963KE03, 1965WA04). Polarization studies have been made by (1961CR1A, 1963KE03, 1965WA04).
The Ep = 2.56 MeV resonance is considerably broader than that observed at the same energy in 9Be(p, α) and 9Be(p, γ) and the two resonances are believed to be distinct (1956MA55). The shape of the resonance and the magnitude of the cross section can be accounted for with J = 3- or 3+: the former assignment is in better accord with charge symmetry and indicates correspondence with 10Be*(7.38). For Jπ = 3-, θ2n = 0.135, θ2p = 0.115 (R = 4.47 fm). The Jπ = 2+ level should contribute about 10% to the cross section at Ep = 2.56 MeV (1962AL1A). See also (1963HA1G, 1963VA1C).
Elastic scattering has been studied for Ep = 0.2 to 2.6 MeV by (1956DE33, 1956MO90): see Table 10.15 (in PDF or PS). Below Ep = 0.7 MeV, only s-waves are present, exhibiting resonance at Ep = 330 keV, J = 1- or 2-: both proton and deuteron widths are large, while θ2α is small. Further s-wave resonances, with J = 2-, appear at Ep = 998 and 1330 keV and a sharp p-wave resonance, J = 0+, occurs at 1084 keV. The behavior of p-wave phase shifts indicates an additional J = 2+ resonance at 980 keV (1956MO90) or near 1100 keV (1956DE33). The behavior at Ep = 2.56 MeV requires J ≥ 2 and a large proton width (1956DE33). See also (1959AJ76, 1963AN12, 1964HO02).
The yield of p0 and p1 (to 2.43 MeV state of 9Be) has been determined by (1961RE03) in the range Ep = 3.6 to 6.0 and 4.2 to 6.0 MeV, respectively, and for Ep = 5.7 to 8 MeV by (1963BL20). Total cross sections and yields of the p1 group have also been determined by (1964BI19) for Ep = 5 to 15 MeV: a broad maximum near Ep = 8 MeV is indicated. Total cross sections have also been measured at Ep = 10.2, 142 and 180 MeV (1961JO17, 1961TA06, 1962IG1A, 1963WI12, 1963WI1D). See also (1961JO18) and (1959AJ76).
Elastic scattering of polarized protons has been studied at Ep = 8.5 and 11.4 MeV (1961RO05, 1961RO13); inelastic scattering has been studied at Ep = 7 and 12 MeV (1965FU03). See also (1964BE03, 1964CR1B, 1965BO1L).
The (p, d) and (p, α) reactions have been studied in the range Ep = 0.8 to 3.0 MeV by (1949TH05, 1951NE03, 1956MO90, 1956WE37), Ep = 1 to 4.6 MeV by (1965MO27) and for Ep = 3.5 to 12.5 MeV by (1963BL20); the (p, α2) reaction, leading to 6Li*(3.56), has been studied from Ep = 2.3 to 5.4 MeV by (1954MA26, 1956MA55, 1959MA20). Observed resonances are exhibited in Table 10.16 (in PDF or PS).
Both alphas and deuterons are isotropic at the Ep = 0.33 MeV resonance, confirming its s-wave formation: proton and deuteron widths are large, while θ2α is small (1956MO90). A strong maximum for α and d appears at Ep = 0.93 MeV, Γ = 130 ± 30 keV, followed by weaker maxima for d at Ep = 1.25, 1.65 and 2.3 MeV. Alpha particles show a weak effect at the Ep = 2.56 MeV, T = 1 resonance, indicating a small isospin impurity (1956WE37). Angular distributions in the range Ep = 0.4 to 1.0 MeV (1951NE03) and 0.8 to 3.0 MeV (1956WE37) show strong interference effects. Analysis of the latter data suggests contributions from three levels, at Ep = 0.938 (2-), 1.15 (1+) and 1.65 MeV (2-) (1964HO02). There is no evidence of further structure in the yield of d0, α0 or α1 for Ep < 12 MeV: in this range direct interaction appears to dominate (1961RE03, 1963BL20, 1965MO27). Polarization of d0 has been studied by (1960BA26, 1961LA17, 1964BO33).
The yield of 3.56 MeV γ-rays, associated with α2 leading to 6Li*(3.56) (Jπ = 0+; T = 1), shows strong resonances at Ep = 2.56 and 4.49 MeV and a broad rise at Ep = 3.5 MeV, suggesting that these states, which are also observed in (p, n), have T = 1 and are the analogues of 10Be*(7.55, 9.26, 9.4) (1959MA20). See also (1959LE27, 1961BE1E, 1961ST1D).
Neutron groups are observed corresponding to 10B states listed in Table 10.17 (in PDF or PS). There have been various reports of additional states: see (1960HJ01, 1960JU04, 1961GA1G, 1962CO23, 1962MO12, 1963KO15) and (1959AJ76). Thresholds for slow neutron production corresponding to 10B states from 4.77 to 6.57 MeV are reported in Table 10.18 (in PDF or PS) (1954BO79). Angular distributions have been studied at many energies (see (1959AJ76) for a summary of the earlier work and (1960BA46, 1961MO15, 1963FE1B, 1964BU14, 1965SI12)). The data, analyzed by stripping theories, show J ≤ 3 and even parity for the first five states of 10B (1952AJ22, 1961MO15) and for the 5.17 MeV state (1962GA11, 1963RI08) while the 5.11 MeV state is well fitted by lp = 0 (1963RI08).
Observed γ-transitions are listed in Tables 10.7 (in PDF or PS) and 10.19 (in PDF or PS). Reported values of the mean life of the 0.72 MeV state are given in Table 10.20 (in PDF or PS). With an intermediate coupling parameter a/K = 4.75, a mean E2 lifetime of 4 nsec is predicted: the experimental value indicates either a lower value of a/K or some collective enhancement (1957FR1B, 1957KU58, 1962LO02). [Since the 10C β-decay is allowed, J = 0+, 1+ for Ex = 0.72 MeV; the γ-transition from Ex = 1.74 MeV established J = 1+.]
The 1.74 MeV state, J = 0+; T = 1 analogue of 10Be and 10C, decays via the 0.72 MeV state. The 2.15 MeV state decays relatively strongly to Ex = 1.74 MeV, arguing against J = 0, 2, 3: therefore J = 1+. The E2 branch to the ground state is relatively strong compared to IPM predictions (1957KU58). The mean life is 1.35 ± 0.16 psec (1965WA1P).
Correlation measurements in the cascade Ex = 3.59 → 0.7 → g.s. exclude J = 0 or 3 for the 3.59 MeV state (1956SH94); a spin 1 assignment would permit a strong transition to Ex = 1.74 MeV, therefore J = 2+. The 3.59 → 0.7 transition is either M1/E2 = 93/7 or pure E2 (1956SH94). The n-γ correlation is isotropic (1962GA11). The large intensity relative to the ground state transition does not fit the IPM (1963WA17). The mean life is 0.096 ± 0.036 psec (1965WA1P). See also (1959CH28, 1959GO78).
The 4.77 MeV state has Jπ = 2+; T = 0 [see 6Li(α, γ)]. No gamma radiation is observed in the present reaction: Γγ/Γ < 0.05. The relative weakness of the ground-state branch and the absence of the present level in the IPM scheme suggests a collective excitation based on Ex = 0.72 MeV (1963WA17).
Three levels exist near 5 MeV, at 5.11, 5.17 and 5.18 MeV. For the Ex = 5.17 MeV level, the small Γα and large Γγ suggest T = 1 (1959WA16) [confirmed in 10B(d, d')]: Γα ≈ Γγ = 0.6 eV (1963WA17), Γγ/Γ = 0.7 ± 0.35 (1962WA21), Γγ/Γ=1 ± 0.2 (1963RI08). The mean life is < 0.08 psec (1965WA1P). Angular correlations confirm the even parity assignment and indicate Jπ = 2+ (1962GA11, 1963WA17). The 5.18 MeV level is excited only weakly, if at all, in the present reaction (1963FE1B, 1963RI08).
At E(3He) = 5.7, 8.8 and 10.2 MeV, deuteron groups are observed corresponding to the ground state and to states at 0.72, 1.74, 2.15 and 3.58 MeV (1959HI69, 1960HI08: see Table 10.21 (in PDF or PS)). Angular distributions of deuterons to these states have been determined at a number of energies up to E(3He) = 25 MeV (1959HI69, 1960HI08, 1960WE04). Deuteron groups have also been observed to 10B*(4.77, 5.11, 5.17, 5.92, 6.03, 6.13 and 6.57 MeV). There is no indication of earlier reported levels at Ex = 5.58 and 6.40 MeV (1965CR1C, 1965YO1E). See also (1962WE1C).
Energy levels are reported in 10B [from reaction (a)] at Ex = 10.25, 10.75, 11.85, 12.25, 14.7 and 16.9 MeV, assuming that the neutron transitions are to the ground state of 9B. The giant dipole resonance appears to peak at 11 MeV (1962FI07). Cross sections have been measured with monoenergetic γ-rays for Eγ = 8.9 to 10.8 MeV: the value at 8.9 MeV leads to Γγ = 0.6 ± 0.3 eV for the Ex = 8.89 MeV level(s) (1964GR40). For reactions (b), (c), (d), see (1959AJ76) and (1962CH26, 1962VO1D).
Elastic scattering at θ = 180° gives evidence of an M3 contribution (1965GO1K: see also (1965RA1D)). At Ee = 41.5 MeV (θ = 180°) evidence is reported for the M1 excitation of three states with Jπ = 2+, 3+ or 4+ at Ex = 7.9, 11.8 and 14.0 MeV, with Γγ in the range 10 to 40 eV (1962ED02). At Ee = 55 MeV, transitions are observed to 10B*(6.02 ± 0.02 and 7.48 ± 0.02 MeV), the latter with Γ = 40 keV, Γγ(M1) = 11 ± 2 eV, assuming Jπ = 2+ (1965SP04: see Ex = 7.47, Table 10.15 (in PDF or PS)). See also (1959ME24, 1962BA1D, 1963GO04, 1963RO1M). At 100 - 200 MeV, (1965FR07) find strong E2 excitation of the 6.02 MeV level.
Excited states observed in inelastic scattering are listed in Table 10.22 (in PDF or PS). Levels observed at Ex = 5.92, 6.03, 6.13 and 6.55 MeV correspond well with those reported in 9Be(d, n)10B: no level at Ex = 6.43 MeV is seen in the present reaction. A broad level at Ex = 7.00 MeV may correspond to a peak reported in 9Be(p, d) at Ep = 0.48 MeV. The J = 2-; T = 1, 7.48 MeV state is seen here, but not in (d, d') (1964AR04). At Ep = 17.9 MeV angular distributions are strongly peaked forward. Comparison of σ(p, p') with E2 transition rates suggests that the strongest (p, p') transitions correspond to states having large E2 coupling to the ground state: the strength of the 6.04 MeV 4+ level is particularly significant (1962SC12), B(E2) = 29 fm4 (1964JA03). At Ep = 185 MeV, the Q = -6.1 MeV peak is dominant. Others are observed corresponding to Ex = 0, 2.2, 3.6, 5.2, 7.55, 11.0 and 13.0 MeV. The angular distribution of the Q = -7.55 MeV group is similar to that of the Q = -3.6 MeV group of 6Li (1965HA17). Inelastic cross sections at Ep = 153 MeV yield |M|2 = 11, 0.02, and 0.66 for γ-transitions from 10B*(2.15) to g.s., 0.7 and 1.74 (1961CL09).
At Ep > 3 MeV, γ-rays with Eγ = 710 ± 15, 1023 ± 5, 1438 ± 5, 2120 ± 60, 2880 ± 10 and 3560 ± 50 keV are observed (1957HU79, 1957MC35). Upper limits to the transitions 1.74 → g.s. and 3.59 → 1.74 are 2 and 3% (1964SI03). See also (1965SE1F).
The summed proton energy spectrum, observed at Ep = 150 to 460 MeV shows peaks corresponding to removal of an l ≠ 0 proton at Q = -6.7, -11.9 and -17.1 MeV; for removal of an l = 0 proton, Q = -30.5 MeV (1966TY01). See also (1962DI1A, 1963BE42, 1964BA1C, 1964LI1D, 1965RI1A) and 9Be.
Deuteron groups have been observed corresponding to eleven excited states of 10B: see Table 10.22 (in PDF or PS). The absence of the groups (upper limit to intensity 1.5% - 4%) corresponding to the 1.74 and 5.17 MeV states is good evidence of their T = 1 character (1962AR02). See also (1959TO1A, 1962SL03).
The half life is 19.48 ± 0.05 sec (1962EA02), 19.27 ± 0.08 sec (1963BA52): Eβ+(max) = 1.865 ± 0.015 MeV (1963BA52). The β+ decay is to the first two excited states of 10B: relative transition probabilities to the 0.72, 1.74 and 2.15 MeV levels are 98.4/1.65 ± 0.2/< 0.1 (1953SH38): ft (from τ1/2 = 19.41 sec, Qm above) are 1.0 × 103 and 2.2 × 103 to the 0.72 and 1.74 MeV states, respectively (1966BA1A).
At Ep = 19 MeV, the ground state and the first four excited states have been observed. From the angular distributions, analyzed by PWBA, ln = 1, θ2 = 0.011, 0.029, 0.011 and 0.0031 (1961LE1A, 1963LE03). At Ep = 155 MeV, deuteron groups are reported to states at 0, 2.0, 5.0, 6.9 and 11.4 MeV (1963BA2F). See also (1956RE04, 1960NE1C, 1961CL09, 1964SH07).
Reported levels are listed in Table 10.23 (in PDF or PS). No evidence is found for previously reported levels at Ex = 2.86, 5.58 and 6.40 MeV (1963GA03, 1965GO05). See also (1965RO01). The apparent absence of the Ex = 5.18 MeV group is ascribed partly to its breadth and partly to its presumptive two-excited nucleon character (1965GO05). The angular distributions of alpha particles corresponding to the lower states indicate strong direct interactions, l = 1 at E(3He) = 2.3 to 5.5 MeV (1960TA12, 1965FO06: see also (1965GO05)); the distributions of α2 (Ex = 1.74 MeV) vary strongly with energy (1965FO06). Alpha-gamma coincidence studies yield Γγ/Γ < 4 × 10-4 for 10B*(4.77), ≈ 1 for 10B*(5.17) (1965RO01). See also (1961BO33, 1964EL1B, 1964GA1B). The τm of the 1.74 MeV state is 0.15 ± 0.02 psec (1965LO04).
Alpha groups have been observed to all of the known states of 10B up to 5.1 MeV: the intensity of the α2-group to the 0+; T = 1 state at 1.74 MeV is usually sharply reduced (1957EL12, 1961PE09, 1961YA08, 1962AR02, 1963AL16, 1963YA1B, 1965BA06, 1965VO1B, 1966HA09); but its yield varies appreciably with small energy changes (1963AL16). The identification of the α-groups to the 5.1 MeV states indicates that the T = 1 state at 5.17 MeV is not excited at Ed = 10 MeV (1962AR02). See Table 10.22 (in PDF or PS). Angular distributions of the α0-, α1-, α3- and α4-groups have been determined for Ed = 9.2 to 19.7 MeV (1961YA08, 1963YA1B, 1965BA06). See also (1958CA1F, 1959HE1C, 1961GA13, 1963JA03, 1963PE07, 1964BA54).