(See Energy Level Diagrams for 9C)
GENERAL: References to articles on general properties of 9C published since the previous review (1988AJ01) are grouped into categories and listed, along with brief descriptions of each item, in the General Tables for 9C located on our website at (nucldata.tunl.duke.edu/nucldata/General_Tables/9c.shtml).
Ground state properties:
The r.m.s. matter radius of 9C is 2.42 ± 0.03 fm has been deduced from interaction cross sections on Be, C, and Al at E ≈ 730 MeV/A (1996OZ01) [see also for derived proton matter, charge and neutron matter r.m.s. radii]. Interaction cross sections have also been measured on C, Al, Sn, and Pb at E ≈ 285 MeV/A (1997BL08). See also reaction 7.
The half-life of 9C is 126.5 ± 0.9 msec: see (1974AJ01). New information on the decay scheme is given in (2000GE09, 2001BE51) and the data of (2000GE09) has been the subject of a separate R-matrix fit (2001BU05). The decay is complex; see reaction 10 in 9B.
The cross section has been determined at E ≈ 14.4 MeV/A and used to determine the asymptotic normalization coefficient for 9C → 8B + p and S18 = 45 ± 13 eV · b (Ecm = 1 - 100 keV) for the 8B(p, γ)9C reaction (2001BE45).
Cross section data from one-proton removal reactions with 9C [see reaction 7] have been used to determine the asymptotic normalization coefficient for 9C → 8B + p and S18(0) for the 8B(p, γ)9C reaction; S18(0) = 46 ± 6 eV · b (2002TR14) and S18(0) = 49 ± 4 eV · b (2003EN05) [see reaction 2 and (2003MO12); theor.]. The 8B(p, γ)9C reaction has also been studied by Coulomb dissociation in inverse kinematics (2003MO23).
The ground state of 9C has been observed in the angular range 0° to 12° at E(7Li) = 350 MeV (2001CA37).
At E(3He) = 74.1 MeV 6He groups are observed to the ground state and to a state at Ex = 2218 ± 11 keV, Γ = 100 ± 20 keV: see (1984AJ01).
At E(3He) = 76.6 MeV a new 9C level at Ex = 3.3 ± 0.05 MeV is claimed in addition to 9C*(0, 2.2). There is evidence for a broad level at Ex ≈ 4.3 MeV that could be the analog of the 4.3 MeV level of 9Li and is expected to have a width of ≈ 2.6 MeV: see (1991GO13).
One-proton and two-proton removal cross sections have been measured on C, Al, Sn, and Pb targets at E ≈ 285 MeV/A (1997BL08), on a C target at E ≈ 78.3 MeV/A (2003EN05), and on a Si target at E = 20 - 70 MeV/A (2004WA06). Eikonal theory is used in (2003EN05) and (2004WA06) to extract quenching factors (≈ 0.82) which renormalize theoretical p-shell spectroscopic factors to reproduce the measured one-nucleon removal cross sections. See also reaction 3.