Single-particle widths in ~(208)Bi and ~(209)Bi determined from the inelastic proton scattering by ~(207)Pb and ~(208)Pb

摘要

Single-particle widths in ~(209)Bi for all particle orbits s_(1/2), d_(3/2), d_(5/2), g_(7/2), g_(9/2), i_(11/2), j_(15/2),and for the hole orbits p_(1/2), p_(3/2), f_(5/2), f_(7/2) are deduced from the study of about fifty states in ~(208)Pb with rather pure particle-hole configurations. Relative single-particle widths of the 0+ isobaric analog resonance (IAR) in ~(208)Bi for the orbits p_(3/2), f_(5/2), f_(7/2) are deduced from the ~(207)Pb(p, p') reaction. The~(207)Pb(p, p') and ~(208)Pb(p, p') reactions via IAR were studied in a scattering chamber experiment of the Max-Planck institute for nuclear physics (Heidelberg, Germany) at scattering angles 40? ≤ θ ≤ 170?. The semiconductor detectors yielded a resolution of 12-15 keV. Proton energies E_p = 14.99, 16.30, 16.45,16.60, 17.40, 17.47, 17.75MeV covered the g_(9/2), j_(15/2), d_(5/2), g_(7/2), and d_(3/2) IARs in ~(209)Bi, and 11.0 < E_p < 11.8MeV the 0_(g.s.)~+ IAR in ~(208)Bi. The differential cross sections for nearly 70 levels in ~(208)Pb were determined with an uncertainty of the solid angle of about 2%. Similar measurements of ~(208)Pb(p, p') with the Q3D magnetic spectrograph of the Maier-Leibnitz-Laboratorium (Garching, Germany) 35-45 years later yielded a resolution of about 3 keV. The uncertainty of the differential cross section was 10-30%. Scattering angles covered 20? ≤ θ ≤ 115? and θ = 138?. The nonresonant (p, p') reaction often dominates at scattering angles θ ≤ 100?. Therefore, only the combination of the two data sets, i) backward angles, precise solid angles but modest resolution, ii) medium scattering angles and high resolution, allows to determine in an iterative manner both the structure of particle-hole states in 208Pb and the relevant single-particle widths in 209Bi.