We present new Sigma beam asymmetry data for eta meson photoproduction on the proton, using a novel tagged, laser backscattered, linearly polarized photon beam up to 1.1 GeV. The data show large, positive asymmetries, at all incident photon energies. In addition to the S-11(1535) and D-13(1520) resonances necessary to reproduce the cross sections, P-13(1720) and D-15(1675) "four stars" resonances contribute to the Sigma observable, but cannot reproduce the strong forward asymmetries measured at energies higher than 900 MeV.

We present new $\ensuremath{\Sigma}$ beam asymmetry data for $\ensuremath{\eta}$ meson photoproduction on the proton, using a novel tagged, laser backscattered, linearly polarized photon beam up to 1.1 GeV. The data show large, positive asymmetries, at all incident photon energies. In addition to the ${S}_{11}(1535)$ and ${D}_{13}(1520)$ resonances necessary to reproduce the cross sections, ${P}_{13}(1720)$ and ${D}_{15}(1675)$ ``four stars'' resonances contribute to the $\ensuremath{\Sigma}$ observable, but cannot reproduce the strong forward asymmetries measured at energies higher than 900 MeV.

The GRAAL facility produces a highly polarized gamma-ray beam by Compton scattering of laser photons on the electrons of the European Synchrotron Radiation Facility (ESRF) at Grenoble. Preliminary results have been obtained with the LAGRANGE detector showing its excellent performances.

The odd-odd nucleus Au-196 has been studied by the Au-197 (p, d)Au-196 reaction at an incident proton energy of 25 MeV and with an energy resolution of 12 keV. From measurements at 12 angles, l = 1, 3, and 6 transfers were clearly characterized. Level energies, l values, and absolute spectroscopic factors have been obtained, and for negative parity levels, comparisons of energies, spins, and strengths have been made with theoretical calculations performed within the framework of the extended supersymmetry scheme. Tentative spins are suggested for several levels, and a levels scheme for Au-196 is proposed.

196Au has been studied with an energy resolution of 12 keV via the 197Au(p,d)196Au reaction, using a 25 MeV proton beam from the Orsay MP tandem and the split pole spectrometer. The angular distributions, measured at 12 angles, permit to clearly characterize the l=1,3 and 6 transfers. Data concerning the energies, l values and absolute spectroscopic factors have been obtained; a comparison is made, for negative parity levels, between these results and theoretical energies, spins and strengths calculated in the framework of the extended supersymmetry. A preliminary level scheme is proposed for 196Au and a few tentative spin attributions are suggested.

Abstract Electromagnetic properties of excited states of 69Ge have been studied using the 55Mn(16O, pn) reaction. Investigation of the decay scheme included branching ratios, mixing ratios and angular distributions. Assuming that 69Ge is described by a system consisting of a 68Ge excited core coupled with a neutron in the g 9 2 state, we obtain a striking similarity in the two modes of decay.

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The $^{70,72,74,76}\mathrm{Ge}(d, ^{3}\mathrm{He})^{69,71,73,75}\mathrm{Ga}$ reactions have been studied at 26 MeV with 15-keV resolution full width at half maximum using a tandem accelerator and split pole magnetic spectrometer. The spectroscopic factors are determined for 15 levels in $^{69}\mathrm{Ga}$ and 11 levels in each of the 3 other Ga isotopes. Level schemes are proposed for the practically unknown $^{73}\mathrm{Ga}$ and $^{75}\mathrm{Ga}$. Anomalies in the occupation numbers are observed between $Z=31 \mathrm{and} 32$ and between $N=40 \mathrm{and} 42$, this last one corresponding to the structural transition observed recently in a comparison of the ($p, t$) and ($t, p$) reactions. These anomalies could be related to changes in the nuclear shape.NUCLEAR REACTIONS $^{70,72,74,76}\mathrm{Ge}(d, ^{3}\mathrm{He})$, $E=26$ MeV; measured $\ensuremath{\sigma}(\ensuremath{\theta})$;; $^{69}\mathrm{Ga}$, $^{71}\mathrm{Ga}$, $^{73}\mathrm{Ga}$, $^{75}\mathrm{Ga}$ deduced levels, $E$, $l$, $j$ $\ensuremath{\pi}$, ${C}^{2}S$; deduced Ge ground-state proton occupation numbers.

The 190Pt(p, t) 18 8Pt reaction has been studied at 25 MeV on an enriched target (35 %). The g.s. ~ g.s. intensity does not differ 2014 within the error limits 2014 from those observed for the other even Pt isotopes and the low-lying O+ level is weakly excited (5 %) as compared with the ground state. There is therefore, no indication of an important shape transition between 190 and 188. Tome 39 ? t’7 1 er SEPTEMBRE 1978 LE JOURNAL DE PHYSIQUE LETTRES

The $^{70}\mathrm{Ge}(p, t)^{68}\mathrm{Ge}$ reaction has been studied at 26 MeV incident energy with an overall resolution of 10 keV using a split-pole spectrometer. Forty-one $^{68}\mathrm{Ge}$ levels, among which twenty-eight are observed for the first time, are populated below 5.2 MeV excitation energy. Angular distributions are obtained, and comparison with distorted-wave Born approximation calculations allows spin and parity assignments. An interesting result is the discovery of the first excited ${0}^{+}$ level at 1.753 MeV as well as seven other ${0}^{+}$ levels above 2 MeV energy. Five ${J}^{\ensuremath{\pi}}={2}^{+}$ and four ${J}^{\ensuremath{\pi}}={4}^{+}$ levels are observed for the first time. We also establish the position of the first ${J}^{\ensuremath{\pi}}={3}^{\ensuremath{-}}$ level at 2.651 MeV and the possibility of a ${J}^{\ensuremath{\pi}}={6}^{+}$ level at 4.456 MeV excitation energy.NUCLEAR REACTIONS $^{70}\mathrm{Ge}(p, t)$, $E=26$ MeV; measured $\ensuremath{\sigma}=\ensuremath{\sigma}(\ensuremath{\theta})$; $^{68}\mathrm{Ge}$ deduced levels up to 5.2 MeV, $J$, $\ensuremath{\pi}$.