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HK: Physik der Hadronen und Kerne
HK 3: Nuclear Physics / Spectroscopy I
HK 3.6: Vortrag
Montag, 11. März 2002, 18:15–18:30, B
Alpha decay of 114Ba — •C. Mazzocchi — GSI, Darmstadt, Germany
Alpha decay is a rich source of nuclear-structure information, offering insight into properties such as ground-state binding energies and spectroscopic factors for α-particle emission, in particular for neutron-deficient isotopes beyond the doubly-magic nucleus 100Sn. Based on this motivation we searched for the α decay of 114Ba (T1/2 = 430−150+300 ms [1]). The 114Ba nuclei were produced through the 58Ni(58Ni,2n) reaction, separated from other reaction products as a mass-separated and chemically clean beam of 114Ba19F+ ions by means of the ISOL facility of GSI Darmstadt, implanted into a stopper foil, and studied by using silicon-detector telescopes for decay spectroscopy.
We measured for the first time the α-particle energy (3410±40 keV) of 114Ba, the half-life (160−60+290 ms) of its daughter nucleus 110Xe, and the α-branching ratios and widths for these two isotopes and for the granddaughter nucleus 106Te [2]. The increase of the α-particle energies along the α-decay chain from 114Ba to 102Sn is a clear signature of the double shell-closure occurring at 100Sn. The experimental values obtained for the α-decay Q values of these three isotopes as well as for the Q value for 12C emission from 114Ba (19000±40 keV) will be dicussed in comparison with theoretical predictions. In view of the large uncertainties of the reduced α-widths, no firm conclusions can be drawn concerning the occurrence of superallowed α decay.
[1] Z. Janas et al., Nucl. Phys. A 627, 119 (1997).
[2] C. Mazzocchi et al., submitted to Phys. Lett. B.