Distorted-Wave Born-Approximation Analysis of theZr90(d,α)Y88andY89(He3,α)Y88Reactions

The levels of ${}_{}{}^{88}{}_{}{}^{}\mathrm{Y}$ have been studied with the ${}_{}{}^{90}{}_{}{}^{}\mathrm{Zr}(d,\alpha )$ and ${}_{}{}^{89}{}_{}{}^{}\mathrm{Y}({}_{}{}^3{}_{}{}^{}\mathrm{He},\alpha )$ reactions with 30-to 40-keV resolution at 15-MeV incident energy. The ($d,\alpha$) angular distributions for transitions to eight prominent levels below 2.2 MeV have been measured over $15°\le \theta \le 150°$. The reliability of parameters entering distorted-wave Born-approximation calculations was checked in detail. The ($d,\alpha$) calculations include the finite-range correction of Chant and Mangelson. The two-nucleon form factors (f.f.) were generated by the oscillator-expansion technique of Drisko and Rybicki, and the effect of residual interaction on the f.f. and angular distributions was studied. An attempt has been made to determine the ($d,\alpha$) absolute normalization constant based on local zero-range calculations, and limits of $20\le D_0^{}{}_{}{}^2\le 30$ have been set. Two-nucleon f.f. generated by the Bayman-Kallio method were compared with the Drisko-Rybicki f.f. The (${}_{}{}^3{}_{}{}^{}\mathrm{He},\alpha$) angular distributions for eight strongly populated levels below 1.7 MeV were measured over $20°\le \theta \le 125°$. Spectroscopic factors and $l_n$ transfers have been extracted with both local zero-range and nonlocal finite-range calculations. The (${}_{}{}^3{}_{}{}^{}\mathrm{He},\alpha$) results were compared with ($d,\alpha$) results to determine unique parities and narrow $J^{\pi }$ limits for the levels studied. ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ and $\alpha$ elastic scattering on ${}_{}{}^{89}{}_{}{}^{}\mathrm{Y}$ have also been measured and optical-model potentials have been determined. Good agreement between this work and the recently reported ${}_{}{}^{85}{}_{}{}^{}\mathrm{Rb}(\alpha ,n\gamma ){}_{}{}^{88}{}_{}{}^{}\mathrm{Y}$ results is seen for the level energy and $J^{\pi }$ assignments made.