Two-quasiproton states in Os190 and Os192 studied with the (t,α) reaction

Level structures up to 3000 keV in Os190 and Os192 have been studied using the Ir191 and Ir193 (t,α) proton pickup reactions with 15 MeV tritons. The α-particle spectra were obtained with the quadrupole-dipole-dipole-dipole magnetic spectrometer with peak widths of ∼11 keV (full width half maximum). This reaction strongly excites the I,Kπ=4,4+ levels at 1162 keV in Os190 and at 1070 keV in Os192, which were previously interpreted as two-phonon γ-vibrational states. The large two-quasiproton amplitude is reasonably explained by assuming single-phonon hexadecapole vibrations which involve the {52 [402], 32 [402]} configuration. Many two-quasiproton states are observed in the energy region 2000-3000 keV. The strongest peaks found at an excitation energy of ∼2600 keV in both Os190 and Os192 may be the remaining portions of the two-quasiproton {52 [402], 32 [402]}I,Kπ=4,4+ states. NUCLEAR REACTIONS Ir191,193(t,α) Os190,192, Et=15 MeV: measured σ(Eα); enriched targets; analyses, DWBA including the (t-α-α′) channel, the strong coupling model, RPA.