The level structure in ${\mathrm{B}}^{10}$ was investigated through the ${\mathrm{Be}}^9(p, p){\mathrm{Be}}^9$ reaction in the energy region $0.8<\mathrm{}{E}_p<1.8\mathrm{}$ MeV. The differential cross section for elastically scattered protons from thin, evaporated ${\mathrm{Be}}^9$ targets was measured in 1-10-keV intervals at c.m. angles of 54.7°, 76.0°, 90.0°, 125.3°, and 161.0°. A 180° double-focusing magnetic spectrometer was used in analyzing the scattered protons at the first four angles, while a high-resolution solid-state detector was used in obtaining the data at 161.0°. The data were fitted by a "multilevel" formula derived from R-matrix theory. Besides the "distant" level contribution, up to three resonance levels of the same spin and parity could be included in the theoretical fitting. Spectroscopic assignments and widths were determined and are discussed for seven resonance levels exhibiting relatively strong proton partial widths, at 945-, 980-, 922-, 1084-, 1200-, 1340-, and 1650-keV incident proton energies. The determined spins and parities are $1^{-}$, $2^{+}$, $2^{-}$, $0^{+}$, $1^{+}$, $2^{-}$, and $2^{+}$, respectively. Total widths $\Gamma$ (keV, in the c.m. system) and the partial-proton-width to total-width ratios $\frac{{\Gamma }_p}{\Gamma }$ corresponding to these levels are 130, 0.38; 65, 1.0; 80, 0.90; 3.3, 1.0; 250, 0.30; 265, 0.90; and ∼800, <0.2. In general, these are in agreement with the earlier published data, although some of the ratios $\frac{{\Gamma }_p}{\Gamma }$ are higher than those previously reported. Uncertainties of some earlier $J^{\pi }$ assignments were resolved. Extensive fittings of the data confirmed the existence of the resonance $E_p=980\mathrm{}$ at keV.

• Received 14 April 1969

DOI:https://doi.org/10.1103/PhysRev.187.1220