LINAC2014 - List of Authors (Okamura, M.)

Paper

Title

Page

Low Charge State Laser Ion Source for the EBIS Injector

64

M. Okamura, J.G. Alessi, E.N. Beebe, T. Kanesue, C.J. Liaw, V. LoDestro, A.I. Pikin, D. Raparia, J. Ritter
BNL, Upton, Long Island, New York, USA
Y. Fuwa, S. Ikeda, M. Kumaki
RIKEN, Saitama, Japan

Funding: NASA
In March 2014, we have successfully commissioned a newly designed low charge high brightness laser ion source (LIS) which delivers various singly charged heavy ions to the electron beam ion source (EBIS) at Brookhaven National Laboratory. Now the LIS is used at routine operation of the RHIC-AGS accelerator complex and is providing stable less-contaminated beams. The laser power density was optimized to provide singly charged ions with low material consumption rate. The nominal laser energy on the target is around 500 mJ with 1064 nm Nd:YAG of the wave length. The induced plasma by the laser is transported through a 3 m pipe to stretch ion beam pulse length to match the EBIS’s requirement and the degradation of the beam current caused by the long drift section of the pipe can be compensated by a longitudinal magnetic filed induced by a coil surrounding the pipe. We also employed a twin laser system to extend the beam width further. At the conference, we will discuss the effect of the new LIS on the various accelerated beams through the EBIS, RFQ and IH-linac.

MOPP112

Beam Dynamics of Multi Charge State Ions in RFQ Linac

317

SUPG015

use link to see paper's listing under its alternate paper code

Y. Fuwa, S. Ikeda, M. Kumaki
RIKEN, Saitama, Japan
Y. Fuwa, Y. Iwashita
Kyoto ICR, Uji, Kyoto, Japan
T. Kanesue, M. Okamura
BNL, Upton, Long Island, New York, USA

Laser ion source with DPIS (Direct Plasma Injection Scheme) is a promising candidate for a pre-injector of the high-intensity accelerator. Eliminating LEBT (Low Energy Beam Transport) where the space charge effect is severe, DPIS provides high current ion beam from laser plasma at the entrance of a RFQ linac and ion beams are injected directly into the RFQ linac. However, the injected beam consists of multi charge state ions and their behavior in RFQ linac has not been well understood. In this research, we study the beam dynamics of multi charge state ions in a RFQ. Using the result of computer simulation, a set of 100MHz 4-rod RFQ vanes, which accelerates Al 12+ ion among various charge states of aluminum ions from 8.9 keV/u to 200 keV/u, is newly designed and fabricated to be tested with beams. The result of beam acceleration test using the vane will be reported.

THPP106

High charge heavy ion production for DPIS

M. Kumaki, Y. Fuwa, S. Ikeda
RIKEN, Saitama, Japan
T. Kanesue, M. Okamura
BNL, Upton, Long Island, New York, USA
M. Washio
RISE, Tokyo, Japan

We have studied intense heavy ion acceleration using direct plasma injection scheme (DPIS). The DPIS consists of a laser ion source and RFQ linac. The produced laser ablation plasma is transported to an RFQ directly and the high brightness heavy ion flux can be efficiently captured by the RF focusing force. In the scheme, one of the most important key issues is how to control the ablation plasma properties. Recently we have tried to use a sub nano second laser system and found that the depth of plasma surface layer, where the laser energy is absorbed, is too thin to heat the plasma. To overcome this issue, the laser beam is split into two beams and those reached at the same spot on the target surface with a few nano second time interval. We will report the experimental results of the new irradiation technique.

Paper	Title	Page
MOPP010	Low Charge State Laser Ion Source for the EBIS Injector	64
	M. Okamura, J.G. Alessi, E.N. Beebe, T. Kanesue, C.J. Liaw, V. LoDestro, A.I. Pikin, D. Raparia, J. Ritter BNL, Upton, Long Island, New York, USA Y. Fuwa, S. Ikeda, M. Kumaki RIKEN, Saitama, Japan
	Funding: NASA In March 2014, we have successfully commissioned a newly designed low charge high brightness laser ion source (LIS) which delivers various singly charged heavy ions to the electron beam ion source (EBIS) at Brookhaven National Laboratory. Now the LIS is used at routine operation of the RHIC-AGS accelerator complex and is providing stable less-contaminated beams. The laser power density was optimized to provide singly charged ions with low material consumption rate. The nominal laser energy on the target is around 500 mJ with 1064 nm Nd:YAG of the wave length. The induced plasma by the laser is transported through a 3 m pipe to stretch ion beam pulse length to match the EBIS’s requirement and the degradation of the beam current caused by the long drift section of the pipe can be compensated by a longitudinal magnetic filed induced by a coil surrounding the pipe. We also employed a twin laser system to extend the beam width further. At the conference, we will discuss the effect of the new LIS on the various accelerated beams through the EBIS, RFQ and IH-linac.

MOPP112	Beam Dynamics of Multi Charge State Ions in RFQ Linac	317
SUPG015	use link to see paper's listing under its alternate paper code
	Y. Fuwa, S. Ikeda, M. Kumaki RIKEN, Saitama, Japan Y. Fuwa, Y. Iwashita Kyoto ICR, Uji, Kyoto, Japan T. Kanesue, M. Okamura BNL, Upton, Long Island, New York, USA
	Laser ion source with DPIS (Direct Plasma Injection Scheme) is a promising candidate for a pre-injector of the high-intensity accelerator. Eliminating LEBT (Low Energy Beam Transport) where the space charge effect is severe, DPIS provides high current ion beam from laser plasma at the entrance of a RFQ linac and ion beams are injected directly into the RFQ linac. However, the injected beam consists of multi charge state ions and their behavior in RFQ linac has not been well understood. In this research, we study the beam dynamics of multi charge state ions in a RFQ. Using the result of computer simulation, a set of 100MHz 4-rod RFQ vanes, which accelerates Al 12+ ion among various charge states of aluminum ions from 8.9 keV/u to 200 keV/u, is newly designed and fabricated to be tested with beams. The result of beam acceleration test using the vane will be reported.

THPP106	High charge heavy ion production for DPIS
	M. Kumaki, Y. Fuwa, S. Ikeda RIKEN, Saitama, Japan T. Kanesue, M. Okamura BNL, Upton, Long Island, New York, USA M. Washio RISE, Tokyo, Japan
	We have studied intense heavy ion acceleration using direct plasma injection scheme (DPIS). The DPIS consists of a laser ion source and RFQ linac. The produced laser ablation plasma is transported to an RFQ directly and the high brightness heavy ion flux can be efficiently captured by the RF focusing force. In the scheme, one of the most important key issues is how to control the ablation plasma properties. Recently we have tried to use a sub nano second laser system and found that the depth of plasma surface layer, where the laser energy is absorbed, is too thin to heat the plasma. To overcome this issue, the laser beam is split into two beams and those reached at the same spot on the target surface with a few nano second time interval. We will report the experimental results of the new irradiation technique.