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A search for the heaviest isotopes of fluorine, neon and sodium was conducted by fragmentation of an intense 48Ca beam at 345 MeV/nucleon with a 20-mm thick beryllium target and identification of isotopes in the large-acceptance separator BigRIPS at RIKEN RIBF. No events were observed for 32,33F, 35,36Ne and 38Na and only one event for 39Na after extensive running [1]. Comparison with predicted yields excludes the existence of bound states of these unobserved isotopes with high confidence levels. The present work indicates that 31F and 34Ne are the heaviest bound isotopes of fluorine and neon, respectively. The neutron dripline has thus been experimentally confirmed up to neon for the first time since 24O was confirmed to be the dripline nucleus nearly 20 years ago [2,3]. These data provide new keys to understanding the nuclear stability at extremely neutron-rich conditions.
Finally, the potential to determine drip-lines for light elements, and move close to drip-lines for higher elements at the Facility for Rare Isotope Beams / MSU [4,5] will be presented. Main requirements for qualitative prediction of production cross sections of unknown isotopes will be discussed.
References:
[1] Location of the neutron drip line at fluorine and neon,
D. S. Ahn, N. Fukuda, H. Geissel, N. Inabe, N. Iwasa, T. Kubo, K. Kusaka, D. J. Morrissey, D. Murai, T. Nakamura, M. Ohtake, H. Otsu, H. Sato, B. M. Sherrill, Y. Shimizu, H. Suzuki, H. Takeda, O. B. Tarasov, H. Ueno, Y. Yanagisawa, and K. Yoshida, accepted for publication in Physical Review Letters.
[2] D. Guillemaud-Mueller et al., Phys. Rev. C 41, 937 (1990).
[3] O. B. Tarasov et al., Phys. Lett. B 409, 64 (1997).
[4] T. Glasmacher, B. Sherrill, W. Nazarewicz, A. Gade, P. Mantica, J. Wei, G. Bollen, and B. Bull,
Nucl. Phys. News 27, 28 (2017).
[5] B. M. Sherrill, EPJ Web of Conferences 178, 01001 (2018).