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Title: Status report of the 28 GHz superconducting electron cyclotronresonance ion source VENUS

Journal Article · · Review of Scientific Instruments
OSTI ID:894232

The superconducting versatile electron cyclotron resonance ECR ion source for nuclear science (VENUS) is a next generation superconducting ECR ion source designed to produce high-current, high-charge-state ions for the 88-Inch Cyclotron at the Lawrence Berkeley National Laboratory. VENUS also serves as the prototype ion source for the rare isotope accelerator RIA front end, where the goal is to produce intense beams of medium-charge-state ions. Example beams for the RIA accelerator are 15 p mu A of Kr17+ (260 e mu A), 12 p mu A of Xe20+ (240e mu A), and 8 p mu A of U28+ (230 e mu A). To achieve these high currents, VENUS has been optimized for operation at 28 GHz, reaching maximal confinement fields of 4 and 3 T axially and over 2.2 T on the plasma chamber wall radially. After a commissioning phase at 18 GHz, the source started the 28 GHz operation in the summer of 2004. During that ongoing 28 GHz commissioning process, record ion-beam intensities have been extracted. For instance, measured extracted currents for the low to medium charge states were 270 e mu A of Xe27+ and 245 e mu A of Bi29+, while for the higher charge states 15 e mu A of Xe34+, 15 e mu A of Bi41+, and 0.5 e mu A of Bi50+ could be produced. Results from the ongoing 28 GHz commissioning as well as results using double-frequency heating with 18 and 28 GHz for oxygen and xenon are presented. The effect of the minimum B field on the ion source performance has been systematically measured for 18 and 28 GHz. In both cases the performance peaked at a minimum B field of about 80 percent of the resonance field. In addition, a strong dependence of the x-ray flux and energy on the minimum B field value was found.

Research Organization:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Organization:
USDOE Director. Office of Science. Office of AdvancedScientific Computing Research. Office of Nuclear Physics
DOE Contract Number:
DE-AC02-05CH11231
OSTI ID:
894232
Report Number(s):
LBNL-59836; RSINAK; R&D Project: N88OPS; BnR: KB0402024; TRN: US0700104
Journal Information:
Review of Scientific Instruments, Vol. 77, Issue 3; Related Information: Journal Publication Date: 2006; ISSN 0034-6748
Country of Publication:
United States
Language:
English