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Abstract: The high resolution beam line for the SHARAQ spectrometer was designed to satisfy the lateral and angular dispersion matching conditions based on the precise ion optical calculation using the measured magnetic field maps of the beam line magnets. The higher order aberration due to the large emittance of the secondary RI-beams was corrected by employing the three octupole magnets. A Monte Carlo calculation was carried out to examine the beam profile on the SHARAQ target, and it was found that the octupole magnets actually correct the higher order aberration. [Copyright &y& Elsevier]

We have launched a new research project named "ONOKORO" to elucidate the formation mechanism of clusters in atomic nuclei. The project comprehensively investigates clustering phenomena in the medium-to-heavy mass region with inverse-kinematics cluster-knockout reactions at the intermediate energy facilities. The new detector array named "TOGAXSI" is under construction for this purpose. It measures scattering angles and the energies of deuterons, tritons, 3 He, and α particles emitted at forward angles from the cluster-knockout reactions. It also measures the recoil protons emitted from the scattering events at large angles. High-angular and high-energy resolutions with wide solid angles are required to achieve a good cluster separation energy resolution and a reasonably high yield. The designed telescope consists of silicon trackers and GAGG:Ce calorimeters. This paper shows the required conditions and design concepts of TOGAXSI. [ABSTRACT FROM AUTHOR]

We developed an N 2 gas scintillation counter as a time-of-flight counter for particle identification of radioactive isotope beams. Radiation damage, which often becomes a problem for high-intensity heavy ion beams, can be prevented by a continuous flow of N 2 gas. The scintillator, with a volume of 60 mm × 60 mm × 100 mm, was filled with N 2 gas at a pressure of approximately 100 kPa. Photons were detected using photomultiplier tubes attached to both sides of the vessel. The main emission wavelength of photons produced in the detector was 300–400 nm. Performance tests confirmed that the detector had sufficient detection efficiency, intrinsic time resolution, and short decay time. Additionally, the detector was demonstrated to be effective for particle identification. [ABSTRACT FROM AUTHOR]

Abstract: The high-resolution SHARAQ spectrometer is now under construction at RI Beam Factory (RIBF) of RIKEN. The spectrometer will be used in nuclear physics experiments in combination with a variety of radioactive isotope (RI) beams. It is designed to achieve a high momentum resolution of δp/p =1/14,700 and a high angular resolution of δθ ∼1mrad. Details of the ion-optical design and the newly-constructed magnets making up the spectrometer are described. [Copyright &y& Elsevier]

Abstract: Ratios of equilibrium charge-state yields for singly to doubly ionized 3He ions at an energy of 420MeV were measured using the Grand Raiden magnetic spectrometer at RCNP. Targets with atomic numbers of 6, 12, 28, 40, 50 and 82 were used. It is found that theoretical calculations for atomic electron-capture and stripping cross sections, which have been successful in describing the data up to beam energies of 200MeV, are also applicable at this higher energy. However, where at the lower energies the stripping cross sections were calculated with a combination of models by Bohr and Gillespie, the best description of the data at E(3He)=420MeV is obtained when using only the model by Gillespie. The experimental results are also compared with calculations using the code CHARGE, originally developed for fast, heavy (Z >29) projectiles, to test the extrapolation to low-Z projectiles. It is found that the code underestimates the production of singly-charged 3He ions, in particular for heavier target nuclei. [Copyright &y& Elsevier]