Direct mass measurements of very neutron-rich calcium isotopes beyond N=34
ORAL
Abstract
Nuclear mass is one of the fundamental quantities expressing its nuclear structure property, and systematic investigation of nuclear masses can illuminate unexpected phenomena such as emergency of new magic numbers and disappearance of conventional magic numbers. In order to obtain the conclusive evidence of the emergency of theoretically-proposed magic number N=34, we have performed an experiment to measure the atomic masses of very neutron-rich calcium isotopes beyond N=34 and have determined the atomic masses of 55-57Ca isotopes successfully for the first time. The experiment was done using the BigRIPS-SHARAQ system at RIKEN RIBF. The masses were determined by TOF-Bρ method in use of CVD diamond timing detectors, LP-MWDC tracking detectors and a PPAC detector. The determined masses made clear a magic nature of neutrons in 54Ca and the emergence of the new magic number 34 became evident in neutron-rich calcium isotopes. In this contribution, we will present details of the experiment and discuss the obtained results.
*This work is financially supported in part by JSPS KAKENHI Grant No. JP14J03376.
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Presenters
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Shin'ichiro Michimasa
- Center for Nuclear Study, the University of Tokyo
- Center for Nuclear Study, University of Tokyo
- CNS, Univ. of Tokyo
- CNS, University of Tokyo