Tübingen 2003 – wissenschaftliches Programm
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HK: Physik der Hadronen und Kerne
HK 43: Kernphysik/Spektroskopie VI
HK 43.7: Vortrag
Donnerstag, 20. März 2003, 18:15–18:30, A
Decay of the 5+ isomer in the N=Z nucleus 78Y — •J. Döring — GSI Darmstadt, Planckstr. 1, 64291 Darmstadt, Germany
The competition of T=0 and T=1 isospins in medium-mass
self-conjugate odd-odd nuclei such as 70Br and 78Y is
being studied at the on-line mass separator of GSI Darmstadt to
gather information about nuclear properties far away from the
line of stability and to test model predictions.
Recently, a β-decaying 5+ (T=0) isomer of 78Y with
a half-life of 5.8(6) s has been identified at an excitation
energy of less than 500 keV [1]. Assuming a well-deformed prolate shape, a
low-lying 2+ state is expected at about 300 keV above the
0+ (T=1) ground state of 78Y, which might be populated by
an isomeric M3 γ decay. Thus a search has been conducted
for this decay branch to deduce the energy of the isomer. The 78Y
nuclei were produced via the 46Ti(40Ca,α p3n) reaction
and separated as molecular 78YF21+ ions by means of the
GSI on-line mass separator. Gamma rays emitted in the 5+ decay
were detected with 17 germanium crystals. By analysing
βγγ coincidences, new low-lying low-spin levels in
the well-deformed daughter nucleus 78Sr have been identified which
complement the nuclear structure information known from previous in-beam
experiments [2].
[1] J. Uusitalo et al., Phys. Rev. C 57, 2259 (1998).
[2] D. Rudolph et al., Phys. Rev. C 56, 98 (1997).