5th Joint Meeting of the APS Division of Nuclear Physics and the Physical Society of Japan
Volume 63, Number 12
Tuesday–Saturday, October 23–27, 2018;
Waikoloa, Hawaii
Session 1WBB: Physics and Chemistry of the Heaviest Elements and Nuclei II
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Chair: Hideyuki Sakai, RIKEN Nishina Center
Room: Hilton Kohala 1
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Tuesday, October 23, 2018
11:00AM - 11:30AM
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1WBB.00001: Spectroscopy and chemistry of the heaviest atoms at LBNL
Invited Speaker:
Jacklyn Gates
In the last two decades, superheavy elements from Z=113-118 have been produced in reactions between 48Ca beams and actinide targets. These new superheavy elements are on the boarder of a theorized doubly-magic spherical-closed shell and have already show some behaviors that are different from isotopes the lighter transactinides, for example, longer half-lives, stabilization against spontaneous fission, and higher production cross sections. For the last decade, LBNL has been interested in studying the spectroscopy and chemistry of these new superheavy elements, in order to gleam more information about these rare nuclei. Here we report on those recent results from LBNL. |
Tuesday, October 23, 2018
11:30AM - 12:00PM
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1WBB.00002: Superheavy nuclei produced with actinides targets at RIKEN
Invited Speaker:
Kouji Morimoto
In the experimental program aiming to discover the 113th element produced by cold fusion reaction 209Bi(70Zn, n)278113, we succeeded to observe three decay chains in 2004, 2005 and 2012. Finally the IUPAC would give the research group the rights of naming and named "Nihonium". For the next, a new program aiming to produce further new elements 119th and 120th via hot fusion reaction was started in collaboration with RIKEN, Oak Ridge National Laboratory (ORNL), Kyushu-Univ., Yamagata-Univ., Osaka-Univ., Niigata-Univ., Tohoku-Univ. and JAEA. The new collaboration group named "nSHE group". In order to study the hot fusion reaction with higher efficiency, new GAs filled Recoil Ion Separator GARIS-II and GARIS-III which has large acceptance were developed. High intensity Vanadium beam was developed by RIKEN Nishina-center(RNC). And rotating Cm target was also developed in collaboration with ORNL. The nSHE group started to perform the experiment for new 119th element by using 51V(248Cm, xn)299-xn119 reaction. The status of the experiment and the future plan will be presented in the workshop. |
Tuesday, October 23, 2018
12:00PM - 12:30PM
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1WBB.00003: Towards In-beam Spectroscopy of the Heaviest Nuclei with Gammasphere and AGFA
Invited Speaker:
Dariusz Seweryniak
Spectroscopy of trans-fermium nuclei around the Z=100 and N=152 deformed shell gaps has been an active area of research at the ATLAS facility at Argonne National Laboratory for many years since the pioneering experiments which led to the observation of a rotational band and K-isomers in 254No using the Gammasphere gamma-ray detector array and the Fragment Mass Analyzer (FMA). Rotational bands and K-isomers in trans-fermium nuclei provide stringent tests of nuclear models used to describe properties of the heaviest elements such as for example their magic numbers which determine the location of the long sought after island of super-heavy nuclei. Recent highlights include first observation of two fast isomers in the heaviest known even-even N=150 isotone 254Rf employing the digital DAQ and the determination of the fission barrier in 254No from g-ray energy-spin distributions obtained with Gammasphere. To extend these studies to even heavier nuclei the Argonne Gas-filled Fragment Analyzer (AGFA) was designed and is currently being commissioned. Due to charge-state focusing AGFA has a factor of about ten higher efficiency compared to the FMA. Gammasphere combined with AGFA offer unparalleled opportunities for in-beam spectroscopic studies of trans-fermium nuclei. During the talk, first results obtained with AGFA and Gammasphere will be presented and prospects for in-beam spectroscopy of the heaviest nuclei will be discussed.
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