A 6 T superconducting solenoid has been constructed to focus heavy ion beams on the production target of radio isotope beams. The design field on axis is 6.2 T with an average current density of 9,600 A/cm 2 . The overall coil length is 1.1 meter, and the coil is divided into three equal-length sections to ease winding and to reduce IR drop through diode connection. A main feature of the system is that the solenoid is conductively cooled by a cryocooler directly attached onto the center coil without liquid helium involved. The solenoid was successfully trained to 6.2 T, and its optical properties were tested in the beamline at RIKEN. The design features and the test results are presented.

Freauencv AbstractA proton linear accelerator has been conceived to be used for Boron Neutron Capture Therapy (BNCT) and Neutron Radiography (NR) at the Korea Cancer Center Hospital in Seoul, Korea. The main accelerator is an RFQ which will accelerate protons from 90 keV to 3.5 MeV with a current of 50 mA in the present design. According to the PARMTEQ calculation, transm.ission efficiency is over 96 % for that current. Beam dynamics and rf properties of the RFQ have been studied along with beam transport and target systems. At present possibility of obtaining funding appears to be low, but we thought it is worthwhile to carry out the design study for the future proposal. MHz INTRODlJCTIONThe Korea Cancer Center Hospital (KCCH) in Seoul has used a MC50 cyclotron (Scandlitronics) for neutron therapy since 1986 [l]. To extentd the hospital's capability for cancer treatment, an accelerator system for BNCT has been proposed. A high current proton beam produces neutrons from the nuclear reactions such as 7Li(p,n)7Be or 'Be(p,n)'B, and then the neutron beam is moderated to epithermal energy (1 eV -10 keV). The reaction process for treatment is l ' B ( n ,~)~L i utilizing a high capture cross section of 'OB for thermal neutrons. The resulting reaction products produce the localized dose on the highly malignant cells [2].Regarding to accelerators for high current proton acceleration, RFQ and RFD seem promising among others. We first chose to study on RFQ siince the average current of near 80 mA has been already achieved by the Chalk River RFQ (to 600 keV) [3].The proton beam energy needed for BNCT is related to the choice of target. A beam energy of 2.5 MeV along with Li target appears to be the best choice in the aspect of neutronics [4]. And we consider that the use of Be target with a higher beam energy of 3.5 MeV is worthy of pursuing as it allows a simpler target system, which fits better into the hospital environment. We chose the current of 50 mA in the present design, which will produce the epithermal neutron flux of 5 x 109/cm2/sec with 7Li target at 2.5MeV.An RFQ to accelerate high current proton beam is highly demanding on diverse applications. As a result, designs of such RFQ accelerators are described by many authors [SI [6]. Our study here aims at oblaining our own design parameters. Besides the RFQ, the beam transport and the target systems have been studied, and some results are given 645 kV Length 4.9 m (3.8 m)in this report. DESIGN STUDY OF AN RFQ ACCELERATORThe accelerator system is composed of ion source, RFQ, low-energy and high-energy beam transport lines. A schematic view of the system is shown in Figure 1. The present design energy is 3.5 MeV with an intermediate goal of achieving 2.5 MeV. Design parameters are obtained using the PARMTEQ code [7] for both energies, and listed in Table 1. The cell parameters of the RFQ is shown in Figure 2 as a function of the longitudinal position. Figure 1: A schematic view of a linear accelerator system for BNCT The transmission efficiency is over 96 % for 50 m...

A superconducting ring cyclotron proposed as a booster of the existing RIKEN Ring Cyclotron (RRC), is composed of six superconducting sector magnets. In each sector magnet, the pole pieces are placed at 4 K to be used as a support structure of the coil vessel against large electromagnetic forces and also to enhance magnetic flux efficiently. The field trimming system suitable for such a cyclotron is thought to be a combination of superconducting and normal trim coils. Considering their differing properties, optimization of a trimming system has been carried out using numerical methods. The trimming system is required to isochronize the magnetic fields for various ions in a wide range of beam energy. Features of the trim coils and the results of optimization are described.