(See Energy Level Diagrams for 9Be)
Special states: (1981PL1A, 1983AU1B, 1983GO28, 1983MI08, 1983VA31, 1984BA49, 1984KO40, 1984VA06, 1984WO09, 1984ZW1A, 1985GO1A, 1985HA1J, 1985PO19, 1985SH24, 1986AN07, 1986WI04, 1987KI1C, 1987VOZU, 1988KW02).
Complex reactions involving 9Be: (1983CH23, 1983EF1A, 1983EN04, 1983GU1A, 1983HA1C, 1983MA53, 1983NA08, 1983OL1A, 1983SO08, 1983ST1A, 1983VA23, 1983WA1F, 1983WI1A, 1984AI1A, 1984GR08, 1984HI1A, 1984IS02, 1984RE14, 1984SI15, 1984XI1B, 1985AG1A, 1985BA1V, 1985BH02, 1985FA02, 1985MA13, 1985MC03, 1985MO08, 1985MO17, 1985MO24, 1985PO11, 1985PO19, 1985RO10, 1985SH1G, 1985TR1B, 1985WA1F, 1985WA22, 1986AV1B, 1986BA2D, 1986BA2H, 1986BA1Q, 1986HA1B, 1986MA19, 1986MA1O, 1986ME06, 1986PO06, 1986RE13, 1986SA30, 1986SH1F, 1986SIZS, 1986SO10, 1986WA1H, 1986WE1C, 1987AK1A, 1987AR19, 1987AU1C, 1987BA38, 1987BO23, 1987DE37, 1987FA09, 1987FE1A, 1987GO17, 1987GR11, 1987HE1H, 1987JA06, 1987KIZY, 1987KO15, 1987KW02, 1987LY04, 1987MU03, 1987MU1D, 1987NA01, 1987PO03, 1987SH23, 1987SI1C, 1987SO13, 1987SO15, 1987ST01, 1987TAZU, 1987TR05, 1987VI14, 1987WA09, 1987YA16, 1987YI1A, 1988BL09, 1988CA06, 1988CH04, 1988GO1F, 1988KA1L, 1988KI05, 1988KR11, 1988POZZ, 1988PO1F, 1988RU01, 1988SA2H, 1988SA19, 1988SH1E, 1988TS03).
Reactions involving pions (See also reactions 2 and 17.): (1983BU1D, 1983GE12, 1983GM1A, 1983HA45, 1983SH19, 1983SU08, 1983ZA1B, 1984BO1H, 1984HA1K, 1984LE11, 1985AR15, 1985BA1V, 1985LA20, 1985IM1A, 1985MA1G, 1985MO1F, 1985PN01, 1986CE04, 1986PE05, 1986RO03, 1986YA1D, 1986ZO1A, 1987AN14, 1987GOZN, 1987GO25, 1987GR1G, 1987MA1I, 1987PI1B, 1988BA82, 1988GIZU, 1988KA1N).
Reactions involving kaons and other mesons: (1983BA71, 1983BR1E, 1983FE07, 1983GE13, 1983GE1C, 1983PO1D, 1983ZA1B, 1984BO1H, 1984MO09, 1985MO1F, 1985YA05, 1986AB07, 1986BA1W, 1986CH1P, 1986DO1B, 1986FI1A, 1986GA1H, 1986YA1D, 1986YA02, 1986ZO1A, 1987PI1B, 1987PO1H, 1987YA1I, 1988BA82, 1988MO1B, 1988KH03, 1988WA1B).
Hypernuclei: (1982DZ1A, 1982MO1B, 1983AU1A, 1983BA1M, 1983BA1D, 1983BR1E, 1983FE07, 1983KO1C, 1983MA64, 1983MI1E, 1983MO1C, 1983OR1A, 1983PO1D, 1983SH1E, 1983ZH1B, 1984BA1N, 1984BO1A, 1984BO1H, 1984CH1G, 1984CH1H, 1984DA1D, 1984JI05, 1984KO1B, 1984MI1C, 1984MI1E, 1984MO09, 1984MO1H, 1984SC1A, 1984ZH1B, 1985HA1P, 1985IK1A, 1985MO1F, 1985YA05, 1985YU1A, 1986BA1W, 1986BO1E, 1986CH1P, 1986DO1B, 1986ER1A, 1986GA1H, 1986MA1C, 1986MA1W, 1986ME1F, 1986PO1G, 1986SH1V, 1986WA1J, 1986YA1D, 1986YA1F, 1986YA02, 1986YU1A, 1987BA2K, 1987BO1L, 1987BO1O, 1987IK1B, 1987JI1A, 1987PI1C, 1987PO1H, 1987WA36, 1987YA1I, 1987YA1C, 1987YA1M, 1988BA82, 1988CH48, 1988HA44, 1988JI1A, 1988MA1G, 1988MO1B, 1988KH03, 1988TA29, 1988WA1B).
Ground-state properties of 9Be: (1983ANZQ, 1983AU1B, 1983KU06, 1983VA31, 1984AN1B, 1984BR25, 1984FR13, 1984MIZM, 1985AN16, 1985AN28, 1985BE59, 1985CL1A, 1985GO1A, 1985HA1P, 1985SA32, 1986CR1B, 1986JI01, 1986GL1A, 1986RO03, 1986SY1A, 1986WI04, 1987HA30, 1987KI1C, 1987LE33, 1987SA15, 1988JO1C, 1988VA03, 1988WO04).
Q = +(53 ± 3) mb: see (1978LEZA).
The interaction nuclear radius of 9Be is 2.45 ± 0.01 fm [(1985TA18); E = 790 MeV/A: see also for derived nuclear matter, charge and neutron matter r.m.s. radii].
The decay 9LiΛ → π- + 9Be* → π- + p + 8Li appears to take place via a T = 3/2 state of 9Be at Ex = 18.6 ± 0.1 MeV (Γ ≤ 300 keV) (1985PN01).
The 0° differential cross section for reaction (a) increases monotonically between Et = 0.10 and 2.4 MeV. A resonance has been reported at Et = 1.875 MeV (9Be*(18.94)). The excitation function for 8Li (reaction (b)) increases monotonically for Et = 0.275 to 1.000 MeV. See (1974AJ01) for references. In the range Et = 2 to 10 MeV the total cross section for reaction (b) shows a broad structure [Γc.m. = 1.5 MeV] at Et = 4.2 MeV (9Be* = 20.5 MeV) (1986AB04; prelim.). Yields and angular distributions for reaction (c) have been measured at Et = 2 to 4.5 MeV (1984LIZY; prelim.). See also (1984AJ01) for other channels and (1984KR1B; theor.).
The energy dependence of the π+ to 9Beg.s. has been measured at E(3He) = 235 to 283 MeV (1984WI06).
For Ed = 0.1 to 1.1 MeV, a resonance in the yield of capture γ-rays is observed at Ed = 360.8 ± 0.3 keV (1987ZI01), 360.7 ± 1.8 keV (1986BE33), corresponding to the excitation of 9Be*(16.97), the second T = 3/2 state [Jπ = 1/2-]: see Table 9.4 (1987ZI01). The reduced width for the isospin "forbidden" deuteron breakup is 5.4 × 10-4 relative to the Wigner limit (1987ZI01). See also (1984AJ01).
The yield of neutrons has been measured for Ed = 0.2 to 23 MeV [see (1979AJ01)] and at Ed = 0.19 to 0.55 MeV (1987DA25). See also (1983SZZY). Polarization measurements have been carried out at Ed = 0.64 MeV and 2.5 to 3.7 MeV [see (1974AJ01)] and at 0.40 and 0.46 MeV (1984GA07; n0). Resonances are reported at 0.36, 0.68 and 0.98 MeV: see Table 9.3 (in PDF or PS) in (1974AJ01). See also (1985CA41; astrophys.).
The yields of α-particles have been measured for Ed = 0.25 to 3.0 MeV: see (1974AJ01, 1979AJ01). Resonances are reported at Ed = 0.75, 1.00 and 2.5 MeV; the latter is broad: see Table 9.3 (in PDF or PS) in (1979AJ01). See also (1983SZZY), (1986DIZT, 1987LE1F; applied) and (1984KR1B; theor.).
Excitation functions and cross sections have been measured for Ed = 0.29 to 7 MeV [see (1974AJ01, 1979AJ01, 1984AJ01)] and 0.60 to 0.95 MeV (1983FI13). See also (1983SZZY, 1986AB04). Resonances are reported at Ed = 0.360(3) [< 0.5], 0.776(7) , 1.027(7) , 2.0 [broad], 2.375(50), 3.220(50) [400 ± 100] and ≈ 4.8 MeV [Γlab in keV] corresponding to 9Be*(16.975 [see also Table 9.4 (in PDF or PS)], 17.298, 17.493, (18.5), 18.54, 19.20, 20.4): for references see Table 9.3 (in PDF or PS) in (1979AJ01) and Table 9.3 (in PDF or PS) in (1984AJ01). The total cross section at the Ed = 0.78 MeV resonance is important because it serves as normalization for the 7Be (p, γ) 8B reaction: the "best" value suggested by (1983FI13) is 157 ± 10 mb. See also (1986BA38) and (1974AJ01, 1984AJ01) for the earlier values. At E(7Li) = 12.2 ± 1.3 MeV [corresponding to Ed = 3.5 MeV] the cross section is reported to be 155 ± 20 mb (1985HA40).
The elastic scattering [Ed = 0.4 to 1.8 MeV] shows a marked increase in cross section for Ed = 0.8 to 1.0 MeV (perhaps related to 9Be*(17.30)) and a conspicuous anomaly at Ed = 1.0 MeV, due to p-wave deuterons [9Be*(17.50)]. The elastic scattering has also been studied for Ed = 1.0 to 2.6 MeV and 10.0 to 12.0 MeV: see (1979AJ01).
The cross section rises steeply from threshold to 95 mb at Ed = 2.4 MeV and then more slowly to ≈ 165 mb at Ed = 4.1 MeV. The t0 yield curve (θlab = 155°) decreases monotonically for Ed = 10.0 to 12.0 MeV: see (1974AJ01).
Observed proton groups are displayed in Table 9.5 (in PDF or PS). The parameters for the particle and γ-decay of observed states are displayed in Tables 9.6 (in PDF or PS) and 9.3 (in PDF or PS). Angular distributions have been reported in the range E(3He) = 0.9 to 14 MeV [see (1974AJ01, 1979AJ01)] and at E(3He) = 14 and 33 MeV (1983LE17, 1983RO22; p0). See also 10B, (1984ME11) and (1986SC35; applications).
Angular distributions of the α-groups to 9Be*(0, 2.43, 6.76) have been measured at E(7Li) = 78 MeV (1986GLZV: prelim.). For the excitation of 4He* see (1987GLZX; prelim.; E(6Li) = 93 MeV). For the earlier work see (1974AJ01).
9Li decays by β- emission with τ1/2 = 178.3 ± 0.4 msec to several 9Be states: see reaction 1 in 9Li and Table 9.7 (in PDF or PS). Measurements of β-α coincidences involving 9Be*(11.28) show contributions from the direct n + 2α breakup process as well as the sequential n-emission to 8Be*(3.0)[Jπ = 2+], followed by breakup into 2α. The branching ratio for the 9Be*(2.43) → 8Beg.s. + n decay is (6.4 ± 1.2)%. 9Be*(2.78) [Jπ = 1/2-] decays mainly to 8Beg.s. + n, presumably by p-wave neutron emission: see (1979AJ01, 1984AJ01) for references, and (1988MI03) for a discussion of the evidence.
The photoneutron cross section has been measured from threshold to 320 MeV: see Table 9.6 (in PDF or PS) in (1966LA04), (1979AJ01) and (1988DI02). A pronounced peak occurs ≈ 29 keV above threshold with σmax = 1.33 ± 0.24 mb. The shape of the resonance has been measured very accurately for Eγ = 1675 to 2168 keV. The FWHM of the peak is estimated to be 100 keV (1982FU11). See also (1983BA52; theor.) and (1987KU05). The cross section then decreases slowly to 1.2 mb at 40 keV above threshold. From bremsstrahlung studies, peaks in the (γ, Tn) cross section are observed corresponding to Ex = 1.80 and 3.03 MeV. At higher energies, using monoenergetic photons, the (γ, Tn) cross section is found to be relatively smooth from Eγ = 17 to 37 MeV with weak structures which correspond to Ex = 17.1, 18.8, 19.9, 21.4, 22.4, 23.8 [± 0.2] MeV and 27 ± 0.5 MeV (broad). In the range Eγ = 18 to 26 MeV the integrated (γ, n0) cross section is < 0.1 MeV · mb, that for (γ, n1) = 2.4 ± 0.4 MeV · mb and the combined integrated cross section for (γ, n) to 8Be*(16.6) and (γ,α0) to 5Heg.s. is 13.1 ± 2 MeV · mb.
The total absorption cross section has been measured for Eγ = 10 to 210 MeV: it rises to ≈ 5 mb at ≈ 21 MeV, decreases to about 0 at 160 MeV and then increases to ≈ 1.5 mb at 210 MeV. An integrated cross section of 156 ± 15 MeV · mb is reported for Eγ = 10 to 29 MeV as is resonant structure at Eγ = 11.8, (13.5), 14.8, (17.3), (19.5), 21.0, (23.0), and (25.0) MeV. Fine structure is also reported at Eγ = 20.47 ± 0.04 and 20.73 ± 0.04 MeV. See (1979AJ01) for references. At Eγ = 1.58 MeV, the cross section for reaction (c) is 0.40 ± 0.18 μb (1983FU13). For the electroproduction and photoproduction of helium nuclei for Ee = 100 to 225 MeV see (1986LI22). For hadron production at high energies see (1983AR24). See also (1987GO1Q), (1982DR08; applications), (1983FR1B, 1984GE1A, 1985AH06, 1985HA1H) and (1983BE45, 1983BO1B, 1983CA22, 1984KO33, 1985GO1A, 1985SH24, 1986JI01, 1987TE1E; theor.).
The yield shows structure in the energy region corresponding to the 9Be levels at 17 - 19 MeV followed by the giant resonance at Eγ ≈ 23 MeV (σ = 2.64 ± 0.30 mb). Structure attributed to eleven states of 9Be with 18.2 < Ex < 32.2 MeV has also been reported. Integrated cross sections have been obtained for each of these resonances, and over different energy intervals for protons leading to 8Li*(0 + 0.98, 2.26 + 3.21, 9.0, 17.0). Angular and energy distributions of photoprotons in various energy intervals have been studied by many groups: see (1974AJ01) for references. For momentum spectra of protons using tagged photons with Eγ = 360 → 600 MeV, see (1984BA09). See also (1984AJ01) and (1984HO24).
The integrated cross sections are reported to be 1.0 ± 0.5 MeV · mb (Eγ = 21 → 33 MeV) for reaction (c) to 7Li*(0 + 0.4) and 0.6 ± 0.3 MeV → mb (Eγ = 25 → 33 MeV) for reaction (d) to 6Li(0). The total integrated cross section for [(γ, p) + (γ, pn) + (γ, d) + (γ, t)] is 33 ± 3 MeV · mb. Resonances in the (γ, d) and (γ, t) cross sections corresponding to 9Be*(26.0 ± 0.2) and 9Be*(32.2 ± 0.3), respectively, have been reported: see (1974AJ01). For momentum spectra of deuterons and tritons at Eγ = 360 → 600 MeV see (1986BA07). Cross sections have been measured in the region of the Δ(1232) resonance by (1984HO09) [(γ, pn), (γ, 2p)], (1987KA13) [(γ, p), (γ, pn), (γ, 2p)] and (1986AR06) [(γ, π0)]. For a high energy study of hadron production see (1983AR24). See also (1986MC1G), (1985HO27, 1985MA1G) and (1983TR04, 1986HO11, 1987LU1B; theor.).
The second T = 3/2 state of 9Be at Ex = 16.98 MeV has been studied in this reaction: see Table 9.4 (in PDF or PS) and reaction 4 (1987ZI01). See also (1986ZI01). With Ebs = 31 MeV eight resonances in (γ, γ') are reported for 17.4 < Ex < 29.4 MeV (1984AL22).
b = 1.5-0.2+0.3 fm [b = oscillator parameter]
< r 2 >1/2M = 3.2 ± 0.3 fm; Ω = 6 ± 2 μN · fm2 [this value of the magnetic
octupole moment implies a deformation of the average nuclear potential].
The elastic scattering of electrons has been studied for Ee up to 700 MeV. Magnetic elastic scattering gives indications of both M1 and M3 contributions. Inelastic scattering populates a number of levels: see Table 9.8 (in PDF or PS). At Ee = 45 and 49 MeV 9Be*(1.68) has a strongly asymmetric line shape, as expected from its closeness to the 8Be + n threshold. The form factor is dominated by a 0p3/2 → 1s1/2 particle-hole transition. 9Be*(2.43) is strongly excited (1987KU05). Form factors have also been measured for 9Be*(0, 14.39, 16.67, 16.98, 17.49) by (1983LO11; Ee = 100.0 to 270.2 MeV). See also (1986MA48, 1987HY01, 1985HY1A). (1984WO09) suggest that the T = 1/2 states [9Be*(16.67, 17.49)] have Jπ = 5/2+ and 7/2+, respectively, and that they have large parentage amplitudes with 8Be*(16.6 + 16.9) [Jπ = 2+], rather than with 8Beg.s.. See (1974AJ01, 1979AJ01, 1984AJ01) for other work and earlier references.
Peaks are observed for the quasifree reaction and for the Δ-resonance at 72 ± 3 and 315 ± 20 MeV at Ee = 537 MeV, and at 115 ± 5 and 375 ± 10 MeV at Ee = 730 MeV. The FWHM widths for the quasifree reaction peaks are 80 ± 5 and 115 ± 5 MeV at Ee = 537 and 730 MeV (1984OC01, 1987OC01). For the deep inelastic cross sections at very high energies see (1984AR02). A parity-violation study using polarized 300 MeV electrons is reported by (1987OT1C; prelim.). See also (1984LI07, 1985LI15, 1986AC1A, 1986BA85, 1986LI1G), (1984DO20, 1985BE1K, 1985KI1A, 1987DE43, 1987FR1B, 1987HO1D, 1987HO1F) and (1983AL04, 1984CH20, 1984LI1E, 1986AZ01, 1986BE1L; theor.).
The elastic scattering, and inelastic scattering to 9Be*(2.43, 6.76) have been studied at Eπ± = 162 and 291 MeV. Quadrupole contributions appear to be quite important for the elastic scattering at 162 MeV, but are much less so at the higher energy: see (1984AJ01) and the "General" section here.
The population of 9Be*(0, 1.7, 2.4, 3.1, (6.8)) has been reported in this reaction: see (1974AJ01). For the neutron decay of these states see Table 9.6 (in PDF or PS). Angular distributions have been measured at En = 3.5 to 14.93 MeV [see (1974AJ01, 1979AJ01, 1984AJ01)], at En = 7 to 15 MeV (1983DA22; n0), 11 to 17 MeV (1985TE01; n0, n2), 14.6 MeV (1985HA02, 1986HAYU; n0) and 14.7 MeV (1984SH01; n0, n2) as well as at En = 9 to 17 MeV (1984BY03; n0, n2; see also for transition to 9Be*(6.76)). See also 10Be, (1986MU07), (1986RO1H) and (1985BE59, 1985DI1B, 1985GU1D, 1987HAZS; theor.).
Elastic and inelastic angular distributions have been studied at many energies in the range Ep = 2.3 to 1000 MeV [see (1974AJ01, 1979AJ01, 1984AJ01)], at Ep = 2.31 to 2.73 MeV (1983AL10; p0), 11 to 17 MeV (1986MU07; p0) and 1 GeV (1985AL16; p0) as well as at Epol. p = 200 MeV (1985GLZZ; p0; prelim.) and 220 MeV (1985RO15; p0, p2). The elastic distributions show pronounced diffraction maxima. A quadrupole-deformed optical-model potential is necessary to obtain a good fit to the p0 and p2 angular distributions: see (1974AJ01). The spin-flip probability at Epol. p = 31 MeV is ≈ 0 for the p2 group, which is expected in view of the collective nature of the transition (1981CO08).
The structure corresponding to 9Be*(1.7) is asymmetric, as expected: see reaction 16 and Table 9.8 (in PDF or PS) for its parameters. [At Ep = 13 MeV the spectra are dominated by 9Be*(2.43) (1987KU05)]. The weighted mean of the values of Ex for 9Be*(2.4) listed in (1974AJ01) is 2432 ± 3 keV. 9Be*(3.1) has Ex = 3.03 ± 0.03 MeV, Γ = 250 ± 50 keV, Jπ = 3.2+, 5/2+. Higher states are observed at Ex = 4.8 ± 0.2, 6.76 ± 0.06 [Jπ = 1/2+, 5/2+, 7/2+ (but see below), Γ = 1.2 ± 0.2 MeV], 7.94 ± 0.08 (Γ ≈ 1 MeV), 11.3 ± 0.2 MeV (Γ ≈ 1 MeV), 14.4 ± 0.3 (Γ ≈ 1 MeV), 16.7 ± 0.3, 17.4 ± 0.3, 19.0 ± 0.4, 21.1 ± 0.5 and 22.4 ± 0.7 MeV [the five highest states are all broad]. For 9Be*(2.4, 6.8) B(E2↑) = 49 ± 6 and 24 ± 4 fm4 and Γ(E2↓) = 0.0025 and 0.10 eV, respectively. The strong population of 9Be*(2.4, 6.8) is consistent with the assumption that they have Jπ = 5/2- and 7/2-, respectively, and are members of the ground state K = 3/2- band. See (1966LA04, 1974AJ01) for references. For K+ production see (1986AB07). See also 10B, (1982BE1E), (1986MU07, 1986RO1H) and (1984SH1K, 1985GU1D, 1986BE1L, 1986NA15, 1987CU01, 1987HA01; theor.).
The reactions (p, 2p)X and (p, pd)X have been studied at Ep = 300 MeV (1983GR21, 1984HE03). For reactions (a) and (c) see also 8Li, 8Be (1985BE30, 1985DO16; 1 GeV) and (1984AJ01). Reaction (c) at Ep = 10 - 24 MeV involves 9Be*(3.0, 4.7): see (1984AJ01). See also (1984WA21). For reactions (b) and (d) at Ep = 58 MeV see 7Li, 6Li and (1985DE17, 1984DE1F). For reactions (e) and (f) see (1985PAZL; Epol. p = 70 MeV). The (p, pα) process (reaction (f)) has been studied at Ep = 150.5 MeV (1985WA13; see for Sα). For inclusive proton spectra yields see (1985SE15). See also (1983AN18, 1987BO1N), (1986CH1J) and (1983KA1A, 1984KO1E, 1985BO1A, 1985GA1A, 1985VD03, 1986ER1A, 1986OS08, 1987HA01; theor.).
Inelastic groups have been reported to 9Be*(1.7, 4.7, 6.8) and to states with Ex = 2431.9 ± 7.0 keV and 3040 ± 15 keV (Γ = 294 ± 20 keV): see (1974AJ01).
Angular distributions of elastically scattered tritons have been measured at Et = 2.10 MeV and at Epol. t = 15 and 17 MeV: see (1974AJ01, 1984AJ01). Reaction (b) at 4.2 and 4.6 MeV proceeds via 9Be*(2.4): see (1974AJ01).
Reaction (b) has been studied in a kinematically complete experiment for E(3He) = 3 to 12 MeV (1986LA26) and 11.9 to 24.0 MeV (1987WA25). For the earlier work see (1984AJ01). See also (1987TR01; theor.).
Angular distributions have been studied at many energies in the range Eα = 5.0 to 104 MeV [see (1974AJ01, 1984AJ01)] and Eα = 23.1 MeV (1984HU1D, 1985HU1B; α0, α2). At Eα = 35.5 MeV, states belonging to the K = 3/2- ground-state band are strongly excited [9Be*(0, 2.43, 6.76, 11.28); it is suggested that the latter has Jπ = (9/2-); see, however, reaction 12]. The first three states belonging to the K = 1/2+ band are also excited [9Be*(1.68, 3.05, 4.70)] (1982PE03; coupled channels analysis). For reaction (b) see (1983ZH09; 18 MeV); Sα = 0.96 [see (1984AJ01)] and (1987WA25; E(3He) = 12 to 24 MeV). See also 8Be, (1987BU27, 1987KO1K) and (1984LI28, 1985SR01; theor.).
Elastic angular distributions have been measured at E(6Li) = 4, 6 and 24 MeV and at E(7Li) = 24 and 34 MeV [see (1979AJ01)] as well as at E(6Li) = 32 MeV (1985CO09; also to 9Be*(2.43)) and 50 MeV (1988TRZY; prelim.) and E(7Li) = 78 MeV (1986GLZV, 1986GLZU; also to 9Be*(2.43, 6.76). For the interaction cross section at E(Li) = 790 MeV/A see (1985TA18).
Elastic angular distributions have been obtained at E(9Be) = 5 to 26 MeV [see (1979AJ01, 1984AJ01)] and at 35 to 50 MeV (1984OM02; also to 9Be*(2.43)). See also (1985JA09). For yields and cross sections see (1984OM03, 1986CU02). For the interaction cross section at E(9Be) = 790 MeV/A see (1985TA18).
Elastic angular distributions have been reported at E(10B) = 20.1 and 30.0 MeV (1983SR01). For yields and cross section measurements see (1983SR01, 1984DA17, 1986CU02). See also (1983DU13) and (1984IN03, 1986RO12; theor.).
Elastic angular distributions have been measured for reaction (a) at E(12C) = 12, 15, 18 and 21 MeV and E(9Be) = 14 to 76.6 MeV [see (1979AJ01, 1984AJ01)] and 158.3 MeV (1984FU10) as well as at E(12C) = 65 MeV (1985GO1H; prelim.; various 12C states). For yield and fusion cross-section measurements see (1983JA09, 1985DE22) and (1984AJ01). Elastic angular distributions for reaction (b) are reported at E(9Be) = 14 to 26 MeV: see (1984AJ01). For yield measurements see (1984DA17, 1986CU02). See also (1983DU13, 1984FR1A, 1984HA53, 1985BE1A, 1985CU1A) and (1982GU21, 1983KA17, 1983OH04, 1983SA20, 1984HA43, 1986BA69, 1986HA13, 1986KA22, 1986MI24; theor.).
Elastic angular distributions have been reported in the range E(16O) = 15 to 30 MeV [see (1979AJ01)], at E(9Be) = 14, 20 and 26 MeV [see (1984AJ01)], 43 MeV (1985WI18) and 157.7 MeV (1984FU10), as well as at E(18O) = 12.1, 16 and 20 MeV [see (1974AJ01)]. See also (1983BI13, 1983DA10, 1985BE1A, 1985CU1A) and (1982GU21, 1983GR18, 1983SA20, 1984HA43, 1988PO1D; theor.).
Elastic angular distributions have been measured for many of these reactions: see (1979AJ01, 1984AJ01). Recently they have been studied on 26Mg and 40Ca at E(9Be) = 43 and 45 MeV, respectively (1985WI18) and on 26Mg, 27Al and 40Ca at E(9Be) = 158.1 - 158.3 MeV (1984FU10). For pion production in reaction (a) see (1985FR13). The interaction cross section for 790 MeV/A 9Be on 27Al has been measured by (1985TA18). Breakup measurements involving 40Ca are reported by (1984GR20). See also (1983BI13, 1984FR1A, 1984HA53) and (1984GU09, 1985AN16, 1985BL18; theor.).
Forward angular distributions have been obtained at Ed = 15.0 MeV for the tritons to 9Be*(0, 1.7, 2.4, 3.1). The ground-state transition is well fitted by l = 1. The transition to 9Be*(1.7) [≈ 165 ± 25 keV] is consistent with Jπ = 1/2+, that to 9Be*(2.4) is quite well fitted with l = 3 [Jπ = 5/2-], and that to 9Be*(3.1) [Γ = 280 ± 25 keV] is consistent with l = 2. No other narrow states are seen up to Ex = 5.5 MeV: see (1974AJ01).
Angular distributions of the 3He groups corresponding to 9Be*(0, 2.4) have been studied at Ed = 11.8, 28 and 52 MeV [the latter also to 9Be*(6.7)], and at Ed = 15 MeV: S = 0.72 and 0.82 for 9Be*(0, 2.4). At Ed = 52 MeV 9Be*(11.3) appears to be strongly populated: see (1979AJ01).
At Et = 12.9 MeV α-groups are observed to the ground state of 9Be and to excited states at Ex = 1.75 ± 0.03, 2.43, 3.02 ± 0.04 (Γ = 320 ± 60 keV), 11.27 ± 0.04 (Γ = 530 ± 70 keV), (14.4) [Γ ≈ 800 keV], 14.39 and 16.67 MeV. The T = 3/2 state 9Be*(14.39) is very weakly populated [≈ 5% of intensity of α2]. The angular distribution of the α2 group shows sharp forward and backward peaking. The α0 group is not peaked in the backward direction: see (1979AJ01). See also (1984AJ01) and (1982CI1A; theor.).
At Ep = 45 MeV angular distributions are reported for the 3He ions corresponding to 9Be*(0, 2.4, 11.8, 13.8, 14.39 [T = 3/2], 15.96 ± 0.04 [T = 1/2]). In addition one or more states may be located at 9Be*(15.13). It is suggested that 9Be*(11.8, 13.8, 15.96) are the Jπ = 3/2-, T = 1/2 analogs to 9Be*(12.06, 14.01, 16.02). Angular distributions are also reported at Ep = 40 MeV. The intensity of the group to 9Be*(3.1) is ≈ 1% of the ground-state group at that energy: see (1974AJ01). The excitation energy of the first T = 3/2 state is Ex = 14392.2 ± 1.8 keV (1974KA15), using Qm.
Alpha groups are reported corresponding to 9Be*(0, 1.7, 2.4, 3.1). The width of 9Be*(1.7) [Ex = 1.70 ± 0.01 MeV] is Γc.m. = 220 ± 20 keV. The weighted mean of the values of Ex of 9Be*(2.4), reported in (1974AJ01), is 2425 ± 3 keV. The 5/2+ state is at Ex = 3.035 ± 0.025 MeV: Γc.m. = 257 ± 25 keV. The ratio Γγ/Γ of 9Be*(1.7) ≤ 2.4 × 10-5, that for 9Be*(2.4) is reported to be (1.16 ± 0.14) × 10-4. Since Γγ is known from (e, e') [see Table 9.8 (in PDF or PS): 0.089 ± 0.010 eV], Γ = 0.77 ± 0.15 keV. See (1974AJ01, 1979AJ01) for references.
Angular distributions for α0 and α2 are reported at Ed = 0.39 to 3.9 MeV and at 12 MeV [see (1974AJ01, 1979AJ01)]. Reaction (b), at Ed = 10.4 and 12.0 MeV, proceeds via 9Be*(2.4) and to some extent via 9Be*(3.1, 4.7) and possibly some higher excited states. The dominant decay of 9Be*(2.4) is to 5He(0) + α while 9Be*(3.1, 4.7) decay to 8Be(0) + n. It should be noted, however, that the peaks corresponding to 9Be*(3.0) have a FWHM of ≈ 1 MeV, which may imply that 9Be*(2.8) is involved.
Angular distributions of the α0 group have been measured at En = 13.9 to 18.8 MeV [see (1974AJ01)] and at 14.1 MeV (1984HA48). 9Be*(1.7, 2.4, 3.1, 6.8) are also populated. Reaction (b) at En = 13 to 18 MeV involves 9Be*(2.4). See (1984HA48) for differential cross sections at 14.1 MeV and for partial and total cross sections.
See (1985DE17; Ep = 58 MeV).
Angular distributions have been obtained at E(3He) = 70 MeV for the transitions to 9Be*(0, 2.4) and 7Be*(0, 0.43). Broad states at 2.9, 4.8 ± 0.2, 7.3 ± 0.2 and 11.9 ± 0.4 MeV are also populated: see (1979AJ01).
See (1986GO1B; E(14N) = 150 MeV).