# Lifetimes of the 2$^+_1$ and the 4$^+_1$ States of $^{148}$Ce and its B$_{4/2}$ Ratio from EXILL&FATIMA Experiment

Abstract : The even-even N=90 isotones with Z=60-66, present an interesting phase transition. This phase transition in nuclei is characterized by a sudden change of the shape of the nucleus [1]. 148Ce lies on the downboundaries of the phase transition region and therefore further elucidate the underlying mechanisms that lend the shape phase transition behavior. 235U and 241Pu fission fragments were measured by a mixed spectrometer consisting of highresolution Ge and fast LaBr3(Ce)-scintillator detectors at the high-flux reactor of the ILL. Prompt γ- ray cascades from the nuclei of interest are selected via Ge-Ge-LaBr3-LaBr3 coincidences. The good energy resolution of the Ge allows precise gates to be set, selecting the cascade, hence, the nucleus of interest. The excellent timing performance of the LaBr3 detectors in combination with the General Centroid Difference method [2] allows the measurement of lifetimes in the ps range in preparation for the FATIMA experiment at FAIR. The first results on neutron-rich 148Ce are presented.
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Conference papers

http://hal.in2p3.fr/in2p3-01520330
Contributor : Michel Lion <>
Submitted on : Wednesday, May 10, 2017 - 12:48:11 PM
Last modification on : Tuesday, May 22, 2018 - 9:48:11 PM

### Identifiers

• HAL Id : in2p3-01520330, version 1

### Citation

P. Koseoglou, V. Werner, N. Pietralla, S. Ilieva, C. Bernards, et al.. Lifetimes of the 2$^+_1$ and the 4$^+_1$ States of $^{148}$Ce and its B$_{4/2}$ Ratio from EXILL&FATIMA Experiment. Shapes and Symmetries in Nuclei: from Experiment to Theory Workshop (SSNET 2016), Nov 2016, Gif sur Yvette, France. ⟨in2p3-01520330⟩

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