ECRIS2012 - Table of Session: THXO (Superconducting Sources)

Paper

Title

Page

Optimization of the New SC Magnetic Structure Design with a Hybrid Magnet

149

D. Xie, W. Lu, L.Z. Ma, L.T. Sun, X.Z. Zhang, H.W. Zhao, L. Zhu
IMP, Lanzhou, People's Republic of China

In the development of the next generation ECRISs, so far either a set of full NbTi or full Nb₃Sn magnets has been proposed to construct the magnet system. However, the single set of magnets may not be the optimum in terms of the field strength and configuration. An optimization of the new SC magnetic structure with a set of hybrid magnets (NbTi and Nb₃Sn) is being investigated. With the hybrid magnet the optimized new magnetic system is capable of producing field maxima of 9.0 T on axis and 4.0 T at the plasma wall, which are 30 and 10% higher than the previously proposed magnetic structure to be built with a set of full NbTi magnets. In addition, the axial length of the optimized magnetic structure has been slightly shrunk resulting in a more compact system. This new magnetic field profile is high enough for operation frequency up to 56 GHz. The design features and the preliminary force/stress analyses of the optimized new SC magnetic structure will be presented and discussed.

Slides THXO01 [2.603 MB]

THXO02

Current Developments of the VENUS Ion Source in Research and Operations

153

J.Y. Benitez, K.Y. Franzen, C.M. Lyneis, L. Phair, M.M. Strohmeier
LBNL, Berkeley, California, USA
G. Machicoane
FRIB, East Lansing, Michigan, USA
L.T. Sun
IMP, Lanzhou, People's Republic of China

The VENUS ion source functions as a research and development tool in the ECR community as well as an injector for LBNL's 88-Inch cyclotron. In order to meet the needs of both the ECR community and users at the 88-Inch cyclotron, technology such as ovens and a sputter probe have been developed for introducing metals into the plasma. Using a modified high temperature oven, VENUS has produced 450 eμA of ²³⁸U³³⁺ and 400 eμA of ²³⁸U³⁴⁺, twice the required Uranium beam current needed for FRIB. In addition, after upgrading its high voltage capabilities VENUS produced 11emA of ⁴He²⁺, a capability that remains unparalleled by other ECR ion sources. In addition to its recent record high intensities VENUS is also being developed to deliver low intensity, ultra high charge state ions for the cocktails beams, where many species are produced simultaneously for use by the BASE Facility. ¹²⁴Xe⁴³⁺ is now in regular production for the 16 MeV/u cocktail, and development of ²⁰⁹Bi⁵⁶⁺ for the 10 MeV/u cocktail is in progress and has been accelerated through the 88-Inch cyclotron. This paper presents the latest work towards integrating the VENUS ion source into our research and operational goals.

Slides THXO02 [8.391 MB]

THXO03

Recent RIKEN 28 GHz SC-ECRIS Results

159

Y. Higurashi, M. Fujimaki, H. Haba, O. Kamigaito, M. Kidera, M. Komiyama, J. Ohnishi, K. Ozeki
RIKEN Nishina Center, Wako, Japan
T. Aihara, M. Tamura, A. Uchiyama
SHI Accelerator Service Ltd., Tokyo, Japan

For increasing the beam intensity of highly charged heavy ions at RIKEN RIBF, we constructed new SC-ECR ion source. In the spring of 2011, we injected 28GHz microwave into the ion source and obtained first beam. Since then, we made several test experiments for increasing the beam intensity of highly charged Xe and U ion beam, and produced ~60 eμA of U³⁵⁺, ~90 eμA of U³³⁺ at the injected RF power of ~2 kW using sputtering method. In case of Xe²⁵⁺, 250 euA was obtained at RF power of 1.7 kW. Using sputtering method, we produced U³⁵⁺ ion beam longer than one month for the RIBF experiment without break. In the beginning of 2012, we installed additional GM-JT refrigerator to increase the cooling power at 4.2 K, then the total cooling power became higher than 9 W. Using it, we can use higher than 8 W of cooling power for heat load due to the absorbed X-rays. In this summer, we will install the new plasma chamber made of Al for increasing the cooling power. We will also use high temperature oven to increase the U vapor. In this contribution, we report the recent modification of the ion source and test experiments for production of U and Xe ion beam.

Slides THXO03 [49.487 MB]

THXO04

SECRAL status and future challenge

H.W. Zhao, W. Lu, L.T. Sun, D. Xie, X.Z. Zhang
IMP, Lanzhou, People's Republic of China

SECRAL, the superconducting ECR ion source at IMP, has been in routine operation for the HIRFL accelerator complex since May 2007. The total operation beam time provided by SECRAL has so far exceeded 9500 hours. In most cases SECRAL has been operating at 18 GHz for the accelerator complex, and only operating at 24 GHz for the very high charge states and very heavy ion beams such as Bi and U beams. Uranium beam was tested at 24 GHz with ion sputtering in which 160 eμA of ²³⁸U³³⁺ was produced, and ²³⁸U³²⁺ beam was delivered to the accelerator continuously for almost one month. Beam long-term stability and emittance at high rf power of 24 GHz were studied. The operation status and the latest performance of SECRAL ion source will be presented. A new heavy ion accelerator facility HIAF has been proposed at IMP. HIAF requests an ion source capable of producing a pulse beam of 2.0 emA of ²³⁸U³⁴⁺. A next generation superconducting ECR ion source with operating frequency up to 50-60 GHz is under consideration in which a few options for the superconducting magnet configuration are being studied. Technical challenges for the next generation ECR ion source will be reviewed.

Slides THXO04 [12.086 MB]

Paper	Title	Page
THXO01	Optimization of the New SC Magnetic Structure Design with a Hybrid Magnet	149
	D. Xie, W. Lu, L.Z. Ma, L.T. Sun, X.Z. Zhang, H.W. Zhao, L. Zhu IMP, Lanzhou, People's Republic of China
	In the development of the next generation ECRISs, so far either a set of full NbTi or full Nb₃Sn magnets has been proposed to construct the magnet system. However, the single set of magnets may not be the optimum in terms of the field strength and configuration. An optimization of the new SC magnetic structure with a set of hybrid magnets (NbTi and Nb₃Sn) is being investigated. With the hybrid magnet the optimized new magnetic system is capable of producing field maxima of 9.0 T on axis and 4.0 T at the plasma wall, which are 30 and 10% higher than the previously proposed magnetic structure to be built with a set of full NbTi magnets. In addition, the axial length of the optimized magnetic structure has been slightly shrunk resulting in a more compact system. This new magnetic field profile is high enough for operation frequency up to 56 GHz. The design features and the preliminary force/stress analyses of the optimized new SC magnetic structure will be presented and discussed.
	Slides THXO01 [2.603 MB]

THXO02	Current Developments of the VENUS Ion Source in Research and Operations	153
	J.Y. Benitez, K.Y. Franzen, C.M. Lyneis, L. Phair, M.M. Strohmeier LBNL, Berkeley, California, USA G. Machicoane FRIB, East Lansing, Michigan, USA L.T. Sun IMP, Lanzhou, People's Republic of China
	The VENUS ion source functions as a research and development tool in the ECR community as well as an injector for LBNL's 88-Inch cyclotron. In order to meet the needs of both the ECR community and users at the 88-Inch cyclotron, technology such as ovens and a sputter probe have been developed for introducing metals into the plasma. Using a modified high temperature oven, VENUS has produced 450 eμA of ²³⁸U³³⁺ and 400 eμA of ²³⁸U³⁴⁺, twice the required Uranium beam current needed for FRIB. In addition, after upgrading its high voltage capabilities VENUS produced 11emA of ⁴He²⁺, a capability that remains unparalleled by other ECR ion sources. In addition to its recent record high intensities VENUS is also being developed to deliver low intensity, ultra high charge state ions for the cocktails beams, where many species are produced simultaneously for use by the BASE Facility. ¹²⁴Xe⁴³⁺ is now in regular production for the 16 MeV/u cocktail, and development of ²⁰⁹Bi⁵⁶⁺ for the 10 MeV/u cocktail is in progress and has been accelerated through the 88-Inch cyclotron. This paper presents the latest work towards integrating the VENUS ion source into our research and operational goals.
	Slides THXO02 [8.391 MB]

THXO03	Recent RIKEN 28 GHz SC-ECRIS Results	159
	Y. Higurashi, M. Fujimaki, H. Haba, O. Kamigaito, M. Kidera, M. Komiyama, J. Ohnishi, K. Ozeki RIKEN Nishina Center, Wako, Japan T. Aihara, M. Tamura, A. Uchiyama SHI Accelerator Service Ltd., Tokyo, Japan
	For increasing the beam intensity of highly charged heavy ions at RIKEN RIBF, we constructed new SC-ECR ion source. In the spring of 2011, we injected 28GHz microwave into the ion source and obtained first beam. Since then, we made several test experiments for increasing the beam intensity of highly charged Xe and U ion beam, and produced ~60 eμA of U³⁵⁺, ~90 eμA of U³³⁺ at the injected RF power of ~2 kW using sputtering method. In case of Xe²⁵⁺, 250 euA was obtained at RF power of 1.7 kW. Using sputtering method, we produced U³⁵⁺ ion beam longer than one month for the RIBF experiment without break. In the beginning of 2012, we installed additional GM-JT refrigerator to increase the cooling power at 4.2 K, then the total cooling power became higher than 9 W. Using it, we can use higher than 8 W of cooling power for heat load due to the absorbed X-rays. In this summer, we will install the new plasma chamber made of Al for increasing the cooling power. We will also use high temperature oven to increase the U vapor. In this contribution, we report the recent modification of the ion source and test experiments for production of U and Xe ion beam.
	Slides THXO03 [49.487 MB]

THXO04	SECRAL status and future challenge
	H.W. Zhao, W. Lu, L.T. Sun, D. Xie, X.Z. Zhang IMP, Lanzhou, People's Republic of China
	SECRAL, the superconducting ECR ion source at IMP, has been in routine operation for the HIRFL accelerator complex since May 2007. The total operation beam time provided by SECRAL has so far exceeded 9500 hours. In most cases SECRAL has been operating at 18 GHz for the accelerator complex, and only operating at 24 GHz for the very high charge states and very heavy ion beams such as Bi and U beams. Uranium beam was tested at 24 GHz with ion sputtering in which 160 eμA of ²³⁸U³³⁺ was produced, and ²³⁸U³²⁺ beam was delivered to the accelerator continuously for almost one month. Beam long-term stability and emittance at high rf power of 24 GHz were studied. The operation status and the latest performance of SECRAL ion source will be presented. A new heavy ion accelerator facility HIAF has been proposed at IMP. HIAF requests an ion source capable of producing a pulse beam of 2.0 emA of ²³⁸U³⁴⁺. A next generation superconducting ECR ion source with operating frequency up to 50-60 GHz is under consideration in which a few options for the superconducting magnet configuration are being studied. Technical challenges for the next generation ECR ion source will be reviewed.
	Slides THXO04 [12.086 MB]