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تسجيل مستخدم جديدHigh precision $^{89}$Y($alpha$,$alpha$)$^{89}$Y scattering at low energies
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Elastic scattering cross sections of the $^{89}$Y($alpha$,$alpha$)$^{89}$Y reaction have been measured at energies E$_{c.m.}$ = 15.51 and 18.63 MeV. The high precision data for the semi-magic $N = 50$ nucleus $^{89}$Y are used to derive a local potential and to evaluate the predictions of global and regional $alpha$-nucleus potentials. The variation of the elastic alpha scattering cross sections along the $N = 50$ isotonic chain is investigated by a study of the ratios of angular distributions for $^{89}$Y($alpha$,$alpha$)$^{89}$Y and $^{92}$Mo($alpha$,$alpha$)$^{92}$Mo at E$_{c.m.} approx$ 15.51 and 18.63 MeV. This ratio is a very sensitive probe at energies close to the Coulomb barrier, where scattering data alone is usually not enough to characterize the different potentials. Furthermore, $alpha$-cluster states in $^{93}$Nb = $^{89}$Y $otimes$ $alpha$ are investigated.
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In this work, we present new data on the $^{89}$Y($gamma$,n) cross section studied with a quasi-monochromatic photon beam produced at the NewSUBARU synchrotron radiation facility in Japan contributing torwards resolving a long standing discrepancy be
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The nuclear level density and the $gamma$-ray strength function have been extracted for $^{89}$Y, using the Oslo Method on $^{89}$Y($p,p gamma$)$^{89}$Y coincidence data. The $gamma$-ray strength function displays a low-energy enhancement consistent
with previous observations in this mass region ($^{93-98}$Mo). Shell-model calculations give support that the observed enhancement is due to strong, low-energy $M1$ transitions at high excitation energies. The data were further used as input for calculations of the $^{88}$Sr($p,gamma$)$^{89}$Y and $^{88}$Y($n,gamma$)$^{89}$Y cross sections with the TALYS reaction code. Comparison with cross-section data, where available, as well as with values from the BRUSLIB library, shows a satisfying agreement.
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