We have investigated the reaction "0(t,p)' 0 using enriched (96.6%) "0 gas in a rotating gas cell and a multiangle spectrograph. Twenty-two angular distributions were measured for levels up to 10.2 MeV. Results are compared with predictions of a recent shell-model calculation. NUCLEAR REACTIONS 80(t, p), E& --15.0 MeV; measured o (E&,8), 0 deduced levels, I, m, J. D%BA analysis. Comparison with shell and weak-coupling models. Enriched gas target.

wide, separated by 22 cm, followed by a deep Faraday cup. For the purpose of determining the emittance area, the cutoff current in the Faraday cup was taken as 10% of the maximum current that could be transmitted through both slits. The entire assembly could be rotated so that the emittance in two perpendicular directions could be measured. It is expected 11 that the emittance of the beam increases with increasing magnetic field in the collision region. At a field of about 3 mT in the collision region, the measured emittance of the D" beam is 2TT mm mrad (MeV) 1/2 . At a field of 30 mT (large enough for strong-field ionization of D°) the measured emittance of the D" beam is as low as 5ir mm mrad (MeV) 1/2 , while at a field of 100 mT (strong-field ionization of H°) the emittance of the H" beam is as low as ll7r mm mrad (MeV) 1/2 . The values of the emittance are low enough for good transmission through tandem accelerators. A recently calculated value 12 for the acceptance of a typical tandem accelerator is 12TT mm mrad (MeV) 1/2 .The ion source described here already yields polarized negative beams of substantially higher current than any other type of polarized negative ion source. The prospects for further increases in beam intensity are encouraging since we have not worked extensively on the development of the Cs° source and more intense Cs° beams can almost certainly be obtained. The method tested here may also have applications to the production of heavier alkali negative ions for heavy-ion nuclear reaction studies.

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The level structure of 'As is probed for the first time and many new states have been identified. Angular distributions were measured and compared with distorted-wave Born approximation calculations, in order to extract I. values and spectroscopic factors. Most of the expected strength for pickup from the 2p and lf5&2 orbitals is observed. The level structure of 'As is fairly similar to that of ' As but differs significantly from that of lighter As isotopes. NUCLEAR REACTIONS "Se(t,a)"As, E =18 MeV; measured o. (E~,O). 'As deduced levels, L, m, (J), spectroscopic factors. DWBA analysis. Enriched target.

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