SRF2011 - List of Authors (Lu, L.)

Paper	Title	Page
MOPO028	Design of CW Superconducting Buncher for RIKEN RI-Beam Factory	138
	L. Lu RIKEN, Saitama, Japan O. Kamigaito, N. Sakamoto, K. Suda, K. Yamada RIKEN Nishina Center, Wako, Japan
	In the RIKEN RI-Beam Factory (RIBF), very heavy ions such as uranium are accelerated with a cascade of a linac injector (RILAC2) and four booster cyclotrons (RRC, fRC, IRC and SRC). There are two charge-stripping sections in this complex. One is located after the RRC (β = 0.16), and the other is after the fRC (β = 0.32). The stripping process causes an increase of the phase width of the beam in the following cyclotrons, which will be reduced by a longitudinal focusing device: a rebuncher. However, design of the rebuncher is challenging because the beam velocity is not so small and the required voltage is estimated to be as high as a few megavolts. We started the design study of the SRF resonator which works at the velocity of β = 0.32. Several types of the rf strucuture have been simulated in this initial design study: a quarter-wavelength resonator (QWR), half-wavelength resonator (HWR), double-spoke resonator, and half-H mode resonator. In addition, we examined the possibility of a new type of coupled TE-mode structure, which is expected to make the voltage distribution more uniform. Basic parameters are calculated and the feasibility is discussed in this paper.

Paper

Title

Page

Design of CW Superconducting Buncher for RIKEN RI-Beam Factory

138

L. Lu
RIKEN, Saitama, Japan
O. Kamigaito, N. Sakamoto, K. Suda, K. Yamada
RIKEN Nishina Center, Wako, Japan

In the RIKEN RI-Beam Factory (RIBF), very heavy ions such as uranium are accelerated with a cascade of a linac injector (RILAC2) and four booster cyclotrons (RRC, fRC, IRC and SRC). There are two charge-stripping sections in this complex. One is located after the RRC (β = 0.16), and the other is after the fRC (β = 0.32). The stripping process causes an increase of the phase width of the beam in the following cyclotrons, which will be reduced by a longitudinal focusing device: a rebuncher. However, design of the rebuncher is challenging because the beam velocity is not so small and the required voltage is estimated to be as high as a few megavolts. We started the design study of the SRF resonator which works at the velocity of β = 0.32. Several types of the rf strucuture have been simulated in this initial design study: a quarter-wavelength resonator (QWR), half-wavelength resonator (HWR), double-spoke resonator, and half-H mode resonator. In addition, we examined the possibility of a new type of coupled TE-mode structure, which is expected to make the voltage distribution more uniform. Basic parameters are calculated and the feasibility is discussed in this paper.