HIGH-RESOLUTION STUDY OF 70GE

Inelastic proton spectra from the 70Ge(p, p′) reaction at 7.0 MeV have been studied with a 65 cm broad-range magnetic spectrograph. The scattered background was reduced by using 0.4 × 8mm slit targets, and an energy resolution of FWHM = 5.5 keV was achieved. Many closely spaced levels were observed up to 4.1 MeV excitation including a 3.4 keV doublet at 2.16 MeV. Level energies have been determined to ±2 keV or better by combining these precise level separations with γ-ray measurements from the 70Ge(p, p′γ) reaction and the 70As(γ)70Ge decay obtained with a 20 cm3 Ge(Li)-NaI(Tl) coincidence-anticoincidence spectrometer. Available information concerning Jπ assignments for levels up to 3.1 MeV is summarized. Comparison of (p, p′) yields at 50° and 90° combined with relative (p, p′) cross sections provide evidence for probable J = 0 states at 2.31, 2.89 and 3.11 MeV. The octupole 31-state is assigned at 2562 keV on the basis of its prominent yield at Ep = 10 MeV. The 22+(E2)02+ transition has been observed in 70Ge with a B(E2) value which is a factor of 14±2 larger than that for the 22+(E2)01+ transition. A nuclear temperature T = 0.7±0.1 MeV was derived from the present data. © 1969.