No abstract available

[en] In this report, as for beam transport system, beam circulation ring and neutron experiment facilities, the outline, present state and so on are described. The details of these installations, experimental design and so on were summarized in previous reports. The particle beam accelerated with the AVF cyclotron enters the ring cyclotron through the C course in N laboratory. The rebuncher is installed upstream of the momentum analysis magnet. The effect of the rebuncher for obtaining the beam with good time resolution is explained. The arrangement of the incident beam transport system is shown. The particle beam accelerated with the ring cyclotron is transported to three laboratories. The arrangement of the laboratories and beam lines is shown. As an example, the dispersion matching of the Grand Raiden and a beam line is considered. The beam circulation ring as the closed beam transmission path is installed in the west laborotory besides the Grand Raiden. Its main particulars are shown. As the neutron experiment facilities, the installation for TOF measurement is constructed. The arrangement of the laboratory with the movable target is shown. Many proposals of the experiment using the facilities have been made. (K.I.)

[en] A nucleus is a many-body quantum system consisting of protons and neutrons with spin=1/2 and isospin=1/2. The structure of atomic nuclei has been investigated with a variety of probes. It was found that the atomic nucleus is a quite unique system where independent particle and collective motions coexist. Today, in order to better understand the atomic nucleus, it becomes more important to clarify microscopic structures produced by the nucleons near the surface in search of various collective motions with large amplitudes and to investigate modifications of nucleon properties in the nuclear medium. Nuclei are sensitive detectors in such interdisciplinary fields as cosmophysics and astrophysics. Information on nuclear structures is indispensable to determine the efficiency of detectors. In this report, we describe research activities on these subjects performed with the RCNP Ring Cyclotron. (author)

[en] The Research Center for Nuclear Physics (RCNP) cyclotron cascade system has been operated to provide high quality beams for various experiments. In order to increase the physics research opportunities, the Azimuthally Varying Field (AVF) cyclotron facility was upgraded recently. A flat-topping system and an 18-GHz superconducting Electron Cyclotron Resonance (ECR) ion source were introduced to improve the beam's quality and intensity. A new beam line was installed to diagnose the characteristics of the beam to be injected into the ring cyclotron and to bypass the ring cyclotron and directly transport low energy beams from the AVF cyclotron to experimental halls. A separator is equipped to provide RI beams produced by fusion reactions at low energy and by projectile fragmentations at high energy. Development has continued to realize the designed performance of these systems.

[en] The upgrade program for increase of the proton beam intensity is in progress at the RCNP cyclotron facility. A 2.45 GHz ECR proton source installed in the injection beam line of the AVF cyclotron, has become available for providing a 15 keV proton beam with intensity of 0.7 mA. Structure of the extraction electrode support of the 2.45 GHz ECR proton source was modified for cooling reinforcement to improve reliability for long term operation. A beam profile monitor was installed in the injection beam line of the AVF cyclotron to measure beam emittance by combining a set of beam slits. Emittance of the 15 keV proton beam from the 2.45 GHz ECR proton source was around 50 π mm-mrad for a vacuum pressure of 3.9x10^-3 Pa, and an extracting voltage of 15 kV. (author)

No abstract available

[en] When rf quadrupole (RFQ) electric field is applied to the circulating beam in a synchrotron, an equation of motion is reduced to Mathieu's Equation. A new analytical method to obtain an approximate solution has been developed, while a numerical computation was usually applied. Translating the behavior of approximate solution into terms of an RFQ electric field and betatron oscillation, a fast tune control can be achieved by rapid tuning of both amplitude and frequency of rf voltage. This process could be applied to suppress a tune shift caused by a space charge effect and to control a slow beam extraction with a low ripple. We have started another analytical computation using Hamiltonian with perturbation of RFQ and the results of this computation also suggest that it is applicable to slow beam extraction. The fast tune controller has been constructed and the beam test will be performed at HIMAC synchrotron in cooperation of RCNP and NIRS. (author)

[en] At Osaka University RCNP cyclotron facility, researches aimed at high-intensity and high quality of the proton beam have been carried out. In the current beam acceleration, there is one problem that the beam generated by the ion source is not injected to the AVF cyclotron downstream efficiently. This is due to the mismatch of acceptance of the AVF and the emittance of the ion source beam. Therefore, in order to realize the beam injection more efficient, it is necessary to measure and evaluate emittance and phase space distributions of the beam rapidly. In our facility, emittance measurements using a slit and a rotating profile monitor have been performed. Thus, the measurement time shortened from 30 minutes to 75 seconds. Thus, it becomes possible to adjust the parameters of the beam transport system and the ion source while the measure emittance, however, in order to improve the control of the beam further, we're aiming the development of real-time emittance measurement system using pepper-pot method. Since we moved a slit in the conventional emittance measurement system mechanically, it took a measurement time of 1 minute because it becomes rate-determining. On the other hand, since there is no mechanical drive in repeated measurements by using a MCP and pepper-pot mask drilled uniformly in pepper-pot method, significant shortening of measurement time is expected than the measurement time using a slit current. (author)

[en] A deuteron-proton scattering experiment, 195 MeV incident energy, was carried out from 15.4deg to 164.3deg by RCNP. The differential cross section and vector polarization resolving power were determined. The results were compared with the theoretical calculation with three-body force effects. The differential cross section and the vector polarization resolving power of the structure at about 120deg was not explained by the two-body force, but they showed remarkable three-body force effects. The results were compared with 95 MeV nd reported by Upsala group, and the angular distribution structure was different from them. Introduction and experiment are described. (S.Y.)

[en] Cross sections and analyzing powers leading to unnatural parity states of 2^-, T = 0 (6.025 and 6.75 MeV), 2^-, T = 1 (8.42 MeV) in ⁴⁰Ca and 6^-, T = 0 (11.58 MeV) and 6^-, T = 1 (14,36 MeV) in ²⁸Si were measured at 65 MeV. These states are pair states of different isospin with same spin-parity. The analyzing powers for a pair of T = 0 and T = 1 excitations in ⁴⁰Ca show an isospin dependence and those in ²⁸Si do not show. The measured angular distributions were compared with microscopic DWBA calculations using two sets of the effective nucleon-nucleon interaction. In the case when the tensor interaction is essential in reproducing the cross section data, good agreements between the calculations and the data for the analyzing powers are obtained. The trends are common to the calculations using two sets of the interaction. (author)