Total neutron cross sections of 27AI and natural barium have been determined at bombarding energies in the range between 5.5 MeV and 9.6 MeV by transmission measurements. Si(Li)-detectors were used for neutron spectroscopy via charged particle reactions in the active volumes of the detectors. The energy spectra of protons and neutrons emitted in proton induced reactions on the targets IO3Rh, 159Tb, and 169Tm were measured at a bombarding energy of 18 MeV and at a variety of emission angles. Angle-integrated emission spectra were calculated and compared with preequilibrium model predictions. The general validity of the extended Griffin model with a systematic empirical set of model parameter values was verified. Evidence was obtained for the conservation (partial or complete) of isospin as a quantum number and for the possible utility of including a pairing energy shift in the calculations.
ROTATIONAL BANDS IN 77KrE. Nolte and P. Vogt, Physik-Department der Technischen Universit~t MHnchen Collective bands in 77Kr have been studied with the help of y singles spectra, u coincidences, u ray angular distributions and recoil-distance life time experiments measured during the irradiation of 63Cu and 64Ni targets with 160 ions. Positive and negative parity bands with the following level energies, spins, and parities have been found: g.s. 5/2+; 150.1 keV 7/2+; 279.1 9/2+; 784. 8ORb, 222Fr ,. For many of these nuclei, the atomic mass excesses could be derived, allowing the comparison of masses of far unstable nuclei with predictions from mass formulae. The odd-odd nuclei 76Rb and 78Rb appear to he I -I I/2 MeV more strongly bound than expected from the systematics.
MASSES AND QB-VALUES OF SHORT-LIVED ISOTOPES