IPAC2011 - List of Authors (Imao, H.)

Paper	Title	Page
TUPS088	Charge Stripping of Uranium-238 Ion Beam with Low-Z Gas Stripper	1746
	H. Imao RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama, Japan N. Fukunishi, A. Goto, H. Hasebe, O. Kamigaito, M. Kase, H. Kuboki, H. Okuno, T. Watanabe, Y. Yano, S. Yokouchi RIKEN Nishina Center, Wako, Japan
	One of the primary goals of the RIKEN RI beam factory is to generate unprecedented high-power uranium beams (up to tens kW), which yield an enormous breakthrough for exploring new domains of the nuclear chart. The development of reliable and efficient charge stripping scheme for such high-power beams is a key unsolved issue, affecting the overall performance of the heavy ion accelerations. A charge stripper using low-Z (low atomic number Z) gas is an important candidate. Because of the suppression of the electron capture process, the high equilibrium mean charge states for the low-Z gas stripper are expected in conjunction with the intrinsic robustness of the gas. There was, however, no direct experimental data of the charge evolution, because of the difficulty in making massive windowless low-Z gas targets. In the present work, the charge evolution of the 238U beams injected at 10.75 MeV/u were investigated using thick hydrogen and helium gas strippers with huge differential pumping system newly developed. In the energy region of interest, near 10 MeV/u, achievable mean charge states around 65+ with the low-Z gas strippers are far superior to those of the medium-Z ones around 55+.

Paper

Title

Page

Charge Stripping of Uranium-238 Ion Beam with Low-Z Gas Stripper

1746

H. Imao
RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama, Japan
N. Fukunishi, A. Goto, H. Hasebe, O. Kamigaito, M. Kase, H. Kuboki, H. Okuno, T. Watanabe, Y. Yano, S. Yokouchi
RIKEN Nishina Center, Wako, Japan

One of the primary goals of the RIKEN RI beam factory is to generate unprecedented high-power uranium beams (up to tens kW), which yield an enormous breakthrough for exploring new domains of the nuclear chart. The development of reliable and efficient charge stripping scheme for such high-power beams is a key unsolved issue, affecting the overall performance of the heavy ion accelerations. A charge stripper using low-Z (low atomic number Z) gas is an important candidate. Because of the suppression of the electron capture process, the high equilibrium mean charge states for the low-Z gas stripper are expected in conjunction with the intrinsic robustness of the gas. There was, however, no direct experimental data of the charge evolution, because of the difficulty in making massive windowless low-Z gas targets. In the present work, the charge evolution of the 238U beams injected at 10.75 MeV/u were investigated using thick hydrogen and helium gas strippers with huge differential pumping system newly developed. In the energy region of interest, near 10 MeV/u, achievable mean charge states around 65+ with the low-Z gas strippers are far superior to those of the medium-Z ones around 55+.