The use of multiple-discrete microwave radiation to enhance the performances of traditional B-minimum ECR ion sources

Technical Report · Wed Dec 31 04:00:00 EST 1997

OSTI ID:314114

Alton, G D; Meyer, F W; Liu, Y; Beene, J R ^[1]; Tucker, D ^[2]

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1. Oak Ridge National Lab., TN (United States)
2. Lambda Technologies, Inc., Raleigh, NC (United States)

The performances of ECR ion sources, in terms of high-charge-state yields and intensities within a particular charge state, can be enhanced by increasing the physical sizes of the ECR zones in relation to the sizes of their plasma volumes. The creation of a large ECR plasma volume permits coupling of more power into the plasma, resulting in the heating of a much larger electron population to higher energies, the effect of which is to produce higher charge state distributions and higher intensities within a particular charge state than possible in present forms of the ECR source. The ECR volumes can be increased in both the spatial and frequency domains. In the spatial domain, large ECR plasma volumes can be effected by designing the central field so that it is uniformly-distributed about the axis of symmetry and of so that its magnitude is in resonance with single-frequency microwave radiation power source used to excite the plasma. Similarly, the frequency domain complements (multiple-discrete frequency, variable frequency or broad bandwidth frequency microwave radiation) can be used to increase the physical sizes of the ECR zones in conventional B-minimum ECR sources. To demonstrate that the frequency domain technique can be used to enhance the performance of a traditional B-minimum ECR ion source, a series of comparative studies was made to assess the relative performance of the ORNL Caprice ECR ion source, in terms of multiple charged ion beam generation capabilities, when excited with high-power, single frequency or multiple-discrete frequency microwave radiation, derived from standard klystron and/or TWT technologies. These studies demonstrate that the most probable charge state for Xe is increased by one charge state unit while the beam intensities for charge states higher than the most probable are increased by factors of {approximately}3 compared to those observed for single frequency plasma excitation. The results of these measurements along with details on the modifications to the injection system required to couple the microwave radiation into the plasma volume of the Caprice source will be presented in this report.

• Research Organization: Oak Ridge National Lab., TN (United States); Lambda Technologies, Inc., Raleigh, NC (United States)
• Sponsoring Organization: USDOE Office of Energy Research, Washington, DC (United States)
• DOE Contract Number: AC05-96OR22464; FG02-96ER86042
• OSTI ID: 314114
• Report Number(s): ORNL/CP--95037; CONF-970958--; ON: DE99001680; BR: KB0402000
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
CHARGE STATES
ECR ION SOURCES
EXPERIMENTAL DATA
MAGNETIC FIELDS
MICROWAVE RADIATION
MULTICHARGED IONS
PERFORMANCE
PLASMA PRODUCTION