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Description
Shape evolution from spherical to deformed nuclear system is being studied to reveal the effect of nuclear interactions as an increase of neutron number in finite quantum many-body system. Neutron-rich odd Xe nuclei with $A$ ~ 140 are located at the northeast transitional-mass region of the doubly-magic $^{132}$Sn ($Z$ > 50 and $N$ > 82). Various nuclear structure with prolate collectivity and octupole correlation are expected to appear this mass region, which is also located around $^{144}$Ba ($N$ = 88), well known for octupole collective properties.
Neutron-rich Xe nuclei are investigated as a part of EURICA campaign at RIBF, RIKEN, based on $\beta$- and isomer-decay spectroscopy. Neutron-rich nuclei with $A$ ~ 140 were produced by in-flight fission of $^{238}$U beam with energy of 345 MeV/nucleon and intensity of ~5 pnA, bombarding on a 3 mm Be target. The fragments were then separated and identified through BigRIPS separator and ZeroDegree spectrometer. Ion and $\beta$ ray were detected by WAS3ABi which consists of 5 DSSSD with 60 vertical and 40 horizontal strips. The parent $\beta$ decaying nucleus was identified by the same detected position of ion and $\beta$ ray at the WAS3ABi. Gamma ray was detected by using EURICA, a $\gamma$ ray detector array consisting of 12 cluster-type Ge detectors.
In this work, neutron-rich odd Xe nuclei are investigated by the $\beta$ decay and the $\beta$-delayed neutron decay of I isotopes and the decay schemes were carefully constructed. Nuclear structure in low-lying states in odd Xe nuclei will be discussed.
