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Multinucleon transfer (MNT) reactions have been demonstrated as a promising pathway to produce and study very neutron-rich heavy nuclei, which can enhance our understanding of the nuclear structural features relevant to the r-process. Translead fragments were produced from the MNT reaction approach using 136Xe+209Bi at IGISOL utilizing an MNT gas cell. The 211Bi, 211mPo, 211Po, and 212mPo nuclei have been observed prominently in the α-decay spectrum. The Geant4 simulation, which played a crucial role in optimizing the experimental parameters, reveals broader angular-energy distributions of MNT fragments released from a thick target compared to those observed from the GRAZING and Langevin models for a mono-energetic beam. Comparative yield analyses of MNT fragments for 136Xe+209Bi and 136Xe+176Yb reactions estimated using Geant4 Simulation as well as analytical formula support the production of many neutron-rich unknown mass nuclei in the rare-earth region. [ABSTRACT FROM AUTHOR]

Astrophysical reactions involving radioactive isotopes (RI) often play an important role in high-temperature stellar environments. The experimental studies on the reaction rates for those are still limited mainly due to the technical difficulties in producing high-quality RI beams. A direct measurement of those reactions would be still challenging in many cases, however, we can make a reliable evaluation of the reaction rates by an indirect method or by studying the resonance prorerties. Here we ntroduce recent examples of experimental studies on such RI-involving astrophysical reactions, performed at Center for Nuclear Study, the University of Tokyo, using the low-energy RI beam separator CRIB. One is for the neutron-induced destruction reactions of 7Be in the Big-Bang nucleosynthesis, and the other is the study on the 22Mg(α, p) reaction relevant in X-ray bursts, which was performed with the resonant scattering method from the inverse reaction channel. [ABSTRACT FROM AUTHOR]

Experimental studies on astrophysical reactions involving radioactive isotopes (RI) often accompany technical challenges. Studies on such nuclear reactions have been conducted at the low-energy RI beam separator CRIB, operated by Center for Nuclear Study, the University of Tokyo. We discuss two cases of astrophysical reaction studies at CRIB; one is for the 7Be+n reactions which may affect the primordial 7Li abundance in the Big-Bang nucleosynthesis, and the other is for the 22Mg(α, p) reaction relevantin X-raybursts. [ABSTRACT FROM AUTHOR]

The cosmological 7Li problem has been one of the big issues left in the standard Big-Bang nucleosynthesis (BBN) model. In order to determine the radiogenic 7Li abundance by the BBN, it is important to know the production and the destruction rate of 7Be rather than 7Li itself. We performed indirect measurements of the relevant neutron-induced reactions 7Be(n; p)7Li and 7Be(n; α)4He simultaneously by the Trojan Horse Method (THM) via the three-body reactions 7Be(d;7Lip)¹H and 7Be(d; αα)¹H. A 7Be radioactive-isotope (RI) beam at 3.16 MeV/u was produced at Center-for-Nuclear-Study RI Beam (CRIB) separator. The Qvalue spectra shows the evidence of the three-body channels of interest. We confirmed that the THM was applicable to the present measurements by the momentum distributions of the spectator proton. Preliminary excitation functions are roughly consistent with the previous studies, moreover providing new data in the BBN energy range, and suggesting that new information about the 7Be(n; p1)7Li* contribution may be obtained by carrying out a further data analysis. [ABSTRACT FROM AUTHOR]

Astrophysical observables that are directly linked to nuclear physics inputs provide critical and stringent constraints on nucleosynthetic models. As 26Al was the first specific radioactivity observed in the Galaxy, its origin has fascinated the nuclear astrophysics community for nearly forty years. Despite extensive research, the precise origins of 26Al remain elusive. At present, the sum of all putative stellar contributions generally overestimates the 26Al mass in the interstellar medium. Among the many reactions that influence the yield of 26Al, radiative proton capture on its isomer 26mAl is one of the least constrained reactions by experimental data. To this end, we developed a 26Al isomeric beam and performed proton elastic scattering to search for low-spin states in 27Si. The experimental method and the preliminary results of this on-going study will be presented. [ABSTRACT FROM AUTHOR]

The advent of radioactive ground-state beams some three decades ago ultimately sparked a revolution in our understanding of nuclear physics. However, studies with radioactive isomer beams are sparse and have often required sophisticated apparatuses coupled with the technologies of ground-state beams due to typical mass differences on the order of hundreds of keV and vastly different lifetimes for isomers. We present an application of a isomeric beam of 26mAl to one of the most famous observables in nuclear astrophysics: galactic 26Al. The characteristic decay of 26Al in the Galaxy was the first such specific radioactivity to be observed originating from outside the Earth some four decades ago. We present a newly-developed, novel technique to probe the structure of low-spin states in 27Si. Using the Center for Nuclear Study low-energy radioisotope beam separator (CRIB), we report on the measurement of 26mAl proton resonant elastic scattering conducted with a thick target in inverse kinematics. The preliminary results of this on-going study are presented. [ABSTRACT FROM AUTHOR]