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Minato, Futoshi*; Naito, Tomoya*; Iwamoto, Osamu
no journal, ,
-ray spectroscopy of heavy actinides at the JAEA Tandem acceleratorOrlandi, R.
no journal, ,
Asai, Masato
no journal, ,
Fission-fragment mass distributions and total kinetic energy (TKE) distributions for the spontaneous fission of 
Fm, 
Fm, 
Md, and Lr have been measured precisely. These nuclei were produced in the multinucleon transfer reactions with the 
O beam and the 
Es target, and in the fusion-evaporation reaction of 
Cm(
N,4n)Lr at the JAEA tandem accelerator facility. The reaction products were mass-separated with the on-line isotope separator (ISOL), and the kinetic energies of spontaneous-fission fragments were measured with 4 pairs of Si semiconductor detectors. The results revealed that the three types of fission, the high-TKE and low-TKE symmetric fissions and asymmetric fission, compete or coexist in this neutron-rich Fm region.
Sako, Hiroyuki
no journal, ,
no abstracts in English
Fujii, Daisuke; Iwanaka, Akihiro*; Hosaka, Atsushi*
no journal, ,
It is useful to investigate the resonant states of nucleons, which are elementary excitations of the QCD vacuum, to further elucidate their properties, because the ground state is dominated by the flavor symmetry. In this study, we investigate the dynamical properties of nucleon resonances, especially the electromagnetic transition amplitudes and decay processes due to strong interactions, using the Sakai-Sugimoto model, which is a top-down approach to holographic QCD. In addition, the gravitational form factor and the stress distribution obtained from it, which have attracted much attention in recent years, were also investigated using the same approach. As a result, we found an interesting relation between the stability condition for the stress distribution and the glueball spectra.
Suzuki, Kei; Fujii, Daisuke; Nakayama, Katsumasa*
no journal, ,
The conventional Casimir effect is defined for photon fields in the QED vacuum, whereas various quasiparticle fields realized in condensed matter systems can lead to novel types of Casimir-effect-like phenomena. In QCD and nuclear physics, such a situation is rare, but there are some possibilities in dense-QCD/nuclear matter. For example, the dual chiral density wave (DCDW) phase has been studied as the ground state of finite-density QCD. In this talk, we discuss the typical features of the Casimir effect in a small-size medium in such a ground state. The Casimir effect from quark fields leads to oscillations of physical quantities as a function of system size. A counterpart of this phenomenon is expected to appear also in Weyl semimetals, and we discuss the comparison between quark matter and Weyl semimetals.
Ito, Yuta
no journal, ,
Precision experiments with short-lived radioactive isotopes (RI) using ion trap techniques are being prepared at the Isotope Separator On-Line (ISOL) facility at the Japan Atomic Energy Agency (JAEA). This offers the potential to expand new research areas in nuclear physics and chemistry, including mass measurements of neutron-rich transactinide nuclei and in-trap gas-phase ion chemistry of superheavy elements. To conduct such experiments, efficient and rapid production of low-energy RI beams with energies in the electron-volt range is required.In this study, we have developed a windowless gas cell cooler and buncher (GCCB) designed to transport 30-keV ion beams from ISOL into a 100-Pa helium gas cell through a entrance hole. It subsequently decelerates and thermalizes ions solely via gas collisions with helium atoms, entirely obviating the need for electrostatic deceleration. Thermalized ions are subsequently transported using radiofrequency (RF) ion guide techniques, which include RF carpet, sextupole ion guide, and quadrupole mass separator. To investigate the gas cell performance and the extraction charge-state systematics, we used both stable and RI beams with a wide range of elements from Rubidium (Z = 37) to Actinium (Z = 89). We found that their extraction charge states were distributed up to 3+ and showed a strong dependence on their atomic structure. Our results allowed us to calculate the charge-changing cross-section at low energies and could help predict the charge state distribution for extracted ion beams of desired elements, such as superheavy elements with production rates of less than one particle per hour. We have also conducted preliminaly experiments to manipulate the charge state with reaction gases to achieve a single charge state. This is aimed to maximize efficiencies for experiments following the GCCB.
Hirose, Kentaro; Nishio, Katsuhisa; Makii, Hiroyuki; Orlandi, R.; Tsukada, Kazuaki; Asai, Masato; Sato, Tetsuya; Ito, Yuta; Suzaki, Fumi; Tanaka, Shoya*; et al.
no journal, ,
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