HIAT2015 - List of Authors (Ohnishi, T.)

Paper	Title	Page
WEPB02	Electron-Beam-Driven RI Separator for SCRIT at RIKEN RI Beam Factory	194
	T. Ohnishi, S. Ichikawa, M. Wakasugi RIKEN Nishina Center, Wako, Japan
	The electron-beam-driven RI separator for SCRIT (ERIS)* was constructed for the SCRIT (Self-Confinement RI Target) electron scattering facility** at RIKEN RI Beam Factory, and it is employed to produce low-energy, high-quality, and high-intensity RI beams used for the electron scattering of unstable nuclei. In ERIS, the photofission of uranium driven by an electron beam is used for RI production, and the estimated production rate of fission products is 2.210¹¹ fissions/s with 30-g uranium and a 1-kW electron beam. The RI production in ERIS has been operated since 2013. Uranium carbide is used as the production target, and it is obtained by the carbothermal reduction of uranium oxide in presence of carbon. The obtained disk was approximately 1 mm in a thickness and 18 mm in a diameter. The average mass concentration of uranium in the disk was estimated as 3.4 g/cm³. Recently, we improved the efficiency of release from the production target and that of transport from the target. As a result, the rate of 132Sn was 2.610⁵ atoms/s with 15-g uranium and a 10-W electron beam. In this paper, we report improvements and the present status of ERIS. * T. Ohnishi et. al: Nucl. Instr. Meth. B317, 357(2013). ** M. Wakasugi et. al: Nucl. Instr. Meth. B317, 668(2013).
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WEPB25	Development of a Buffer Gas-Free Buncher for Low Energy RI Ion Beam	253
	M. Togasaki, K. Kurita, K. Yamada Rikkyo University, Tokyo, Japan M. Hara, T. Ohnishi, M. Wakasugi RIKEN Nishina Center, Wako, Japan R. Toba Nagaoka University of Technology, Nagaoka, Niigata, Japan
	In the SCRIT (Self-Confining RI Ion Target) electron scattering facility* at RIKEN RI Beam Factory, we constructed an ISOL-type RI beam generator named ERIS (Electron-beam-driven RI separator for SCRIT)*. ERIS supplys continuous RI ion beam with the energy of 50 keV at maximum. In order to efficiently inject the RI beam into the SCRIT device equipped in an electron storage ring, it is necessary to provide a 500-us pulsed ion beam without deteriorating of a vacuum level of less than 10^-7 Pa. Therefore, we are developing a buffer gas-free buncher system working under the ultra-high vacuum based on a linear radiofrequency quadrupole (RFQ) trap. Our idea is to make active use of the fringing field at the entrance and the exit to decelerate and stack ions continuously injected into the buncher. Experiment for the performance study is now going on using the stable 133Cs and 23Na ions. In this paper, we will report the latest status of the development and the study of the buncher. M. Wakasugi et. al, Nucl. Instr. Meth. B317, 668 (2013) **T. Ohnishi et. al, Nucl. Instr. Meth. B317, 357 (2013)
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Paper

Title

Page

Electron-Beam-Driven RI Separator for SCRIT at RIKEN RI Beam Factory

194

T. Ohnishi, S. Ichikawa, M. Wakasugi
RIKEN Nishina Center, Wako, Japan

The electron-beam-driven RI separator for SCRIT (ERIS)* was constructed for the SCRIT (Self-Confinement RI Target) electron scattering facility** at RIKEN RI Beam Factory, and it is employed to produce low-energy, high-quality, and high-intensity RI beams used for the electron scattering of unstable nuclei. In ERIS, the photofission of uranium driven by an electron beam is used for RI production, and the estimated production rate of fission products is 2.2*10¹¹ fissions/s with 30-g uranium and a 1-kW electron beam. The RI production in ERIS has been operated since 2013. Uranium carbide is used as the production target, and it is obtained by the carbothermal reduction of uranium oxide in presence of carbon. The obtained disk was approximately 1 mm in a thickness and 18 mm in a diameter. The average mass concentration of uranium in the disk was estimated as 3.4 g/cm³. Recently, we improved the efficiency of release from the production target and that of transport from the target. As a result, the rate of 132Sn was 2.6*10⁵ atoms/s with 15-g uranium and a 10-W electron beam. In this paper, we report improvements and the present status of ERIS.
* T. Ohnishi et. al: Nucl. Instr. Meth. B317, 357(2013).
** M. Wakasugi et. al: Nucl. Instr. Meth. B317, 668(2013).

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WEPB25

Development of a Buffer Gas-Free Buncher for Low Energy RI Ion Beam

253

M. Togasaki, K. Kurita, K. Yamada
Rikkyo University, Tokyo, Japan
M. Hara, T. Ohnishi, M. Wakasugi
RIKEN Nishina Center, Wako, Japan
R. Toba
Nagaoka University of Technology, Nagaoka, Niigata, Japan

In the SCRIT (Self-Confining RI Ion Target) electron scattering facility* at RIKEN RI Beam Factory, we constructed an ISOL-type RI beam generator named ERIS (Electron-beam-driven RI separator for SCRIT)**. ERIS supplys continuous RI ion beam with the energy of 50 keV at maximum. In order to efficiently inject the RI beam into the SCRIT device equipped in an electron storage ring, it is necessary to provide a 500-us pulsed ion beam without deteriorating of a vacuum level of less than 10^-7 Pa. Therefore, we are developing a buffer gas-free buncher system working under the ultra-high vacuum based on a linear radiofrequency quadrupole (RFQ) trap. Our idea is to make active use of the fringing field at the entrance and the exit to decelerate and stack ions continuously injected into the buncher. Experiment for the performance study is now going on using the stable 133Cs and 23Na ions. In this paper, we will report the latest status of the development and the study of the buncher.
*M. Wakasugi et. al, Nucl. Instr. Meth. B317, 668 (2013)
**T. Ohnishi et. al, Nucl. Instr. Meth. B317, 357 (2013)

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reference for this paper to ※ BibTeX, ※ LaTeX, ※ Text, ※ RIS/RefMan, ※ EndNote (xml)