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The level structure of 196po has been studied using a ~6~176 4n) reaction and a recoil-catcher technique to reduce fission. The results showed a sharp drop off in the first (2 +) and (4 +) energies relative to systematics implying an abrupt increase in the quadrupole collectivity at N = 112. In addition, second (2 +) and (4 +) states were identified at 859 and 1388 keV, respectively, suggesting the discovery of a 4p2h deformed band in Po isotopes which is related to known 2p2h proton bands in several Pb isotopes. A prompt la3W(Z~ 5n) experiment located similar second 2 + and 4 + states at 1039 and 1483 keV in ~98po providing corroboration and extended information on the properties of the new Po deformed bands. A measured halflife of 850 (90) ns for the 2491 keV (11-) state in ~96po implied collective E3 contributions to the extracted B (E3; 11 -~ 8 + ) = 27(5) W.u..

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Excited states in 208 Pb have been studied by measuring ␥ rays in time coincidence with reaction charged particles. 208 Pb states were produced with both the 207 Pb(d, p) 208 Pb and 209 Bi(t,␣) 208 Pb reactions. The energy resolution of the particle spectra of 100 keV allowed a rough determination of level excitation, which then was determined with high resolution from the coincident ␥ decay measured in Ge detectors. Many new ␥ transitions have been found and previously unresolved multiplets of states resolved. The data give spectroscopic factors for neutron transfer and proton pickup. Spins and parities of levels could be deduced from their ␥ decays. A least squares fit of all ␥ energies gave very precise ͑0.1 keV͒ level energies. All states predicted by the shell model below 4.6 MeV are now found and their spins determined unambiguously. ͓S0556-2813͑97͒03009-4͔PACS number͑s͒: 21.60. Cs, 23.20.Lv, 25.45.Hi, 27.80.ϩw II. THE 209 Bi"t,␣␥… 208 Pb EXPERIMENT A. Design of the experiment and proceduresThe 209 Bi(t,␣␥) 208 Pb reaction was used to excite levels in 208 Pb. Due to the huge positive energy balance of this

The very neutron deficient nucleus 104Sn has been idehtified in in-beam spectroscopy using the reaction 5oCr(58Ni, 2p2n) and neutron and charged particle multiplicity filter detectors. Excited states up to I-~ 10 and Ex = 4 MeV were observed and the level scheme is discussed in the frame work of the spherical shell model. The spectroscopic approach to the extremely neutron deficient doubly magic 94 has made substantial progress recently. 97Ag [1] and lo0Cd [2] have been studied in-beam and 98Ag in the 13+/EC decay of 98Cd [3] . From these studies fairly good knowledge of the proton-proton.(nn) and proton-neutron (nv) residual interaction and single particle binding energies was obtained. Much less is known about the neutronneutron (vv) interaction in the light semimagic Sn isotopes. Due to the near-degeneracy of the vd5/2, and vg7/2 orbitals at Z=50 the N=56 subshell closure disappears [4,5] and therefore little is known on the vgT/2 2 and vg7/2 d5/2 interaction. The experimental. situation is complicated by the fact that the Sn isotopes with A<105 touch the proton drip line so that they cannot be populated by 13+/EC decay. In the present work we have searched for light Sn isotopes populated in the reaction 5oCr+58Ni at 245 and 250 MeV energy of the Ni beam from the tandemcyclotron combination VICKSI at the Hahn-MeitnerInstitute. The target was a 2.1 mg/cm2 foil of 50Cr enriched to >97 % on a 23 mg/cm2 Au backing. The yrays were detected in the 6 and 12 detector version of OSIRIS [6] with the detectors positioned at 90 ~ and 90 ~ --25 ~ respectively. Evaporation neutrons were measured in a 16 respective 7 segment close packed detector array made from hexagons and pentagons [7].