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Rare isotope Accelerator complex for ON-line experiments (RAON), which is being constructed in Korea, will provide both rare isotope and stable ion beams for various nuclear physics experiments as well as other applications, at a wide energy range up to a few hundreds of MeV/nucleon. The ion beams will be provided to low-energy experimental facilities at RAON such as Korea Broad Acceptance Recoil spectrometer and Apparatus (KoBRA) and Nuclear Data Production System (NDPS). Since the bunch length of some ion beams becomes unsuitably long at the targets of these facilities, a re-bunching system has been designed and developed. Besides, a pre-bunching system based on a fast chopper and a Double Gap Buncher (DGB) has been developed and installed upstream of the Radio-Frequency Quadrupole (RFQ) to lower the repetition rate for the time-of-flight measurements of secondary particles at KoBRA and NDPS. We present the status of the pre-bunching and re-bunching systems for the RAON low-energy experimental facilities. [ABSTRACT FROM AUTHOR]

The SARAF 176 MHz accelerator is designed to provide CW proton/deuteron beams up to 5 mA current and 40 MeV accelerated ion energy. Phase I of SARAF (up to 4–5 MeV) has been installed, commissioned, and is available for experimental work. Phase II of SARAF is currently in the design and first prototyping stage and will contain longer MEBT with three rebunchers and four cryomodules, each consisting of SC HWRs and solenoids. Phase II MEBT line is designed to follow a 1.3 MeV/u RFQ, is 4.5 m long, and contains three 176 MHz rebunchers providing a field integral of 105 kV. Different rebuncher configurations have been studied in order to minimize the RF losses and maximize the shunt impedance. Different apertures have also been tested with the 40 mm diameter required by beam dynamics. The simulations were done using CST Microwave Studio. CEA leads the design for SARAF phase II linac including the MEBT rebunchers and has studied a mixed solid copper and Cu plated stainless steel, 3-gap cavity. SNRC is developing a 4-gap OFHC copper rebuncher as a risk reduction. Both designs are presented and discussed in the paper. [ABSTRACT FROM AUTHOR]

Ultra-cold neutron (UCN) is attractive for a search of the neutron electric dipole moment (nEDM). It is crucial to store UCNs with high density in a bottle for nEDM measurement apparatus. To increase the density, time focusing technique can be useful, where slow neutrons are accelerated and fast neutrons are decelerated by using magnetic potential. This device is called “rebuncher.” The rebuncher consists of a gradient magnet, RF coil, and neutron guide. The magnet generates a field gradient of 3.5 T/m (from 1 T to 0.2 T within 24 cm) in the longitudinal direction. By using anisotropic inter-poles, the magnet is compact and keeps the gradient uniform. The fabricated magnet showed good performance as designed. [ABSTRACT FROM PUBLISHER]