ECRIS2010 - List of Authors (Higurashi, Y.)

Paper

Title

Page

Status of RIKEN SC-ECRIS

8

T. Nakagawa, Y. Higurashi, J. Ohnishi
RIKEN Nishina Center, Wako, Japan
T. Aihara, M. Tamura
SHI Accelerator Service Ltd., Tokyo, Japan

To increase the beam intensity of highly charged heavy ions for RIKEN RIBF project, we constructed and tested RIKEN new SC-ECRIS. After obtaining the first beam in the spring of 2009, we tried to optimize the ion source condition for maximizing the beam intensity with 18GHz microwave. In this experiment, we intensively studied the effect of the magnetic field gradient and ECR zone size on the beam intensity. In this experiment, it was clearly seen that the gentler field gradient and lager ECR zone size give higher beam intensity. Based on these studies, we produced 550μA of Ar¹¹⁺ and 350μA of Ar¹²⁺ at the RF power of 1.8kW. In this summer, we will try use the 28GHz microwaves to increase the beam intensity. In this contribution, we present the structure of the SC-ECRIS and the results of test experiments with 18 GHz microwave in detail. We also present the future plan to increase the beam intensity.

Slides MOCOAK03 [2.366 MB]

TUCOAK04

Production of Highly Charged U Ion Beam from RIKEN SC-ECRIS

84

Y. Higurashi, M. Fujimaki, A. Goto, H. Haba, E. Ikezawa, O. Kamigaito, M. Kase, M. Komiyama, T. Nakagawa, J. Ohnishi, Y. Watanabe
RIKEN Nishina Center, Wako, Japan
T. Aihara, M. Tamura, A. Uchiyama
SHI Accelerator Service Ltd., Tokyo, Japan

In 2008, we successfully produced 345 MeV/u U beam (~0.4 pnA on target) for RIKEN RIBF project. However, to meet the requirement of the RIBF (primary beam intensity of 1pμA on target), we still need to increase the beam intensity. To increase the beam intensity of U ion, we started to make a test experiments for production of U ion beam from the new SC-ECRIS. In this experiment, we produced 2~1.5 pμA of medium charge state U ion (ex., 55 eμA of U³¹⁺, 57 eμA of U²⁷⁺) at the RF power of 1.2 kW with sputtering method. For testing the effect of the ionized gas on the U ion beam, we chose Ar, Ar + O₂ and O₂ gas for producing U ion beam. In this experiment, we observed that the beam intensity of lower charge state of U ion beam (<33+) was increased and the emittance of the U ion beam was decreased from ~0.1 π.mm mrad (1rms) to 0.05 π.mm mrad with adding Ar gas to O₂ gas. Using this method, we supplied U³⁵⁺ beam for ~1 month without break for the RIBF experiment. In this contribution, we present the experimental results for production of U ion beam from SC-ECRIS in detail and future plan to increase the U ion beam intensity.

Slides TUCOAK04 [1.709 MB]

TUCOBK03

Time Evolution of Plasma Potential in Pulsed Operation of ECRIS

93

O.A. Tarvainen, H. A. Koivisto, T. Ropponen, V.A. Toivanen
JYFL, Jyväskylä, Finland
Y. Higurashi, T. Nakagawa
RIKEN Nishina Center, Wako, Japan

The time evolution of plasma potential has been measured in pulsed operation mode with electron cyclotron resonance ion sources at JYFL and RIKEN. Three different ion sources with microwave frequencies ranging from 6.4 to 18 GHz were employed for the experiments. The plasma potential during the preglow and afterglow transients was compared with steady state conditions. The plasma potential was observed to increase 25-75 % during the preglow and 10-30 % during the afterglow. We describe the experimental procedure and present the results of the study in detail.

Slides TUCOBK03 [0.973 MB]

Paper	Title	Page
MOCOAK03	Status of RIKEN SC-ECRIS	8
	T. Nakagawa, Y. Higurashi, J. Ohnishi RIKEN Nishina Center, Wako, Japan T. Aihara, M. Tamura SHI Accelerator Service Ltd., Tokyo, Japan
	To increase the beam intensity of highly charged heavy ions for RIKEN RIBF project, we constructed and tested RIKEN new SC-ECRIS. After obtaining the first beam in the spring of 2009, we tried to optimize the ion source condition for maximizing the beam intensity with 18GHz microwave. In this experiment, we intensively studied the effect of the magnetic field gradient and ECR zone size on the beam intensity. In this experiment, it was clearly seen that the gentler field gradient and lager ECR zone size give higher beam intensity. Based on these studies, we produced 550μA of Ar¹¹⁺ and 350μA of Ar¹²⁺ at the RF power of 1.8kW. In this summer, we will try use the 28GHz microwaves to increase the beam intensity. In this contribution, we present the structure of the SC-ECRIS and the results of test experiments with 18 GHz microwave in detail. We also present the future plan to increase the beam intensity.
	Slides MOCOAK03 [2.366 MB]

TUCOAK04	Production of Highly Charged U Ion Beam from RIKEN SC-ECRIS	84
	Y. Higurashi, M. Fujimaki, A. Goto, H. Haba, E. Ikezawa, O. Kamigaito, M. Kase, M. Komiyama, T. Nakagawa, J. Ohnishi, Y. Watanabe RIKEN Nishina Center, Wako, Japan T. Aihara, M. Tamura, A. Uchiyama SHI Accelerator Service Ltd., Tokyo, Japan
	In 2008, we successfully produced 345 MeV/u U beam (~0.4 pnA on target) for RIKEN RIBF project. However, to meet the requirement of the RIBF (primary beam intensity of 1pμA on target), we still need to increase the beam intensity. To increase the beam intensity of U ion, we started to make a test experiments for production of U ion beam from the new SC-ECRIS. In this experiment, we produced 2~1.5 pμA of medium charge state U ion (ex., 55 eμA of U³¹⁺, 57 eμA of U²⁷⁺) at the RF power of 1.2 kW with sputtering method. For testing the effect of the ionized gas on the U ion beam, we chose Ar, Ar + O₂ and O₂ gas for producing U ion beam. In this experiment, we observed that the beam intensity of lower charge state of U ion beam (<33+) was increased and the emittance of the U ion beam was decreased from ~0.1 π.mm mrad (1rms) to 0.05 π.mm mrad with adding Ar gas to O₂ gas. Using this method, we supplied U³⁵⁺ beam for ~1 month without break for the RIBF experiment. In this contribution, we present the experimental results for production of U ion beam from SC-ECRIS in detail and future plan to increase the U ion beam intensity.
	Slides TUCOAK04 [1.709 MB]

TUCOBK03	Time Evolution of Plasma Potential in Pulsed Operation of ECRIS	93
	O.A. Tarvainen, H. A. Koivisto, T. Ropponen, V.A. Toivanen JYFL, Jyväskylä, Finland Y. Higurashi, T. Nakagawa RIKEN Nishina Center, Wako, Japan
	The time evolution of plasma potential has been measured in pulsed operation mode with electron cyclotron resonance ion sources at JYFL and RIKEN. Three different ion sources with microwave frequencies ranging from 6.4 to 18 GHz were employed for the experiments. The plasma potential during the preglow and afterglow transients was compared with steady state conditions. The plasma potential was observed to increase 25-75 % during the preglow and 10-30 % during the afterglow. We describe the experimental procedure and present the results of the study in detail.
	Slides TUCOBK03 [0.973 MB]