We have designed and upgraded the focal plane polarimeter 2nd-FPP to improve the position and angle resolution. Four MWDCs were newly introduced. The experiment with protons of polarization $P$=0.99 by p-C elastic scattering at 65 MeV was performed at RCNP in order to evaluate the overall performance. The position resolution of about 0.34 mm has been achieved, which is about two orders of...
Neutron-rich nuclei near the neutron number 20 are known to exhibit exotic structure, such as shape deformation of their ground states, contrary to a spherical shape expected from the conventional magicity for the neutron shell. The mass region is called the “island of inversion” and a variety of experimental works has been devoted to study it. To unravel the mechanism to generate the “island...
Understanding nuclear forces is necessary to describe nuclear phenomena, and recently it has become clear that three-nucleon forces, which act between three nucleons, are also essential. We are planning to measure the spin correlation coefficient, one of the spin observables, from deuteron-proton elastic scattering for gathering accurate information on three-nucleon forces.
We use a polarized...
We, the nSHE Research Group, are searching for new elements beyond element 118 (oganesson), i.e. element 119, at RIKEN. The probability of producing superheavy elements by fusion reactions is extremely low. Therefore, it is crucially important to determine the optimal experimental conditions to maximize the production rate, especially by predicting the optimum incident energy that maximizes...
We search for the Electric Dipole Moment (EDM) of Xe atoms using a technique of an artificial-feedback nuclear spin maser. In this study, $^{129}$Xe and 131Xe are used to deduce the isotope-differential EDM as well as to work as comagnetometry. The isotope-differential EDM is deduced from the difference of the precession frequency between $^{129}$Xe and $^{131}$Xe under a magnetic field and...
Rare Isotope Accelerator complex for ON-line experiments (RAON) is currently under construction in Korea. The low-energy experimental facilities in RAON include the Korea Broad Acceptance Recoil spectrometer and Apparatus (KoBRA) and the Nuclear Data Production System (NDPS). One of the objectives at RAON is to provide rare isotope and stable ion beams with a wide energy range, up to a few...
An isomeric state of 45Cr with an excitation energy of 107 keV is of much interest for its nuclear structure in terms of the isospin symmetry. The mirror nucleus of 45Cr, 45Sc, has an isomeric state. The isomeric state of 45Sc (Jπ = 3/2+, Ex = 12.4 keV, T1/2 = 325.8 ms), has been well investigated. However, the half-life of the isomeric state of 45Cr was not measured. In the previous research,...
The mass measurement of proton-rich unstable nuclei in the vicinity of 47Fe has been performed utilizing the TOF-Bρ method with BigRIPS and OEDO-SHARAQ spectrometer at RIBF. In this measurement, the secondary beam included several nuclei with isomeric states in the pf-shell region. The isomer tagging provides us exact particle identification (PID) like a unique fingerprint. Moreover, the...
The study of the p-process is of paramount importance in unraveling the origin of heavy elements in the universe. To describe the entire p-nuclei nucleosynthesis process, a comprehensive reaction network involving over ten thousand nuclear reactions is required, and accurate measurements of some key reaction cross sections are essential for determining reaction rates. 102Pd is one of the more...
Si detectors are extensively applied in the measurement of charged particles produced in fusion reactions. To achieve a relatively low-cost charged-particle detection with the position sensitivity, we have developed a mosaic-type array based on Si photodiodes (Hamammatsu S13955-01). Its high modularity allows one to modify the geometric configuration of the array according to specific...
The permanent electric dipole moment (EDM) of elementary particles is a physical quantity that reflects CP symmetry breaking, and is being explored. In particular, it is theoretically suggested that electron EDMs are amplified as atomic EDMs in heavy elements. In this project, we aim to achieve high-precision EDM measurement using francium (Fr) atoms trapped by laser cooling technique. Toward...
In this presentation, the current status of a comagnetometer which is dedicated
to search for the permanent electric dipole moment of the electron (eEDM) using
francium atoms is discussed. The designed comagnetometer consists of laser-cooled
Rb-87 and Cs-133 atoms trapped simultaneously in an optical lattice in order to
observe the effects of Zeeman shift and vector light shift...
A variety of unstable nuclear beams with atomic numbers (Z) up to 92 can be produced by the projectile fragmentation and in-flight fission from high intensity U beams at RIBF. Recently, it was found that 234−238Np can be created by a proton pickup reaction on 1GeV/nucleon 238U beam. Owing to the recent developments of the high-Z beams at BigRIPS, energy dependence of the proton pickup reaction...
