Separation of beam and electrons in the spallation neutron source H{sup {minus}} ion source
- Oak Ridge National Lab., TN (United States)
- Lawrence Berkeley National Lab., CA (United States)
The Spallation Neutron Source (SNS) requires an ion source producing an H{sup {minus}} beam with a peak current of 35 mA at a 6.2% duty factor. For the design of this ion source, extracted electrons must be transported and dumped without adversely affecting the H{sup {minus}} beam optics. Two issues are considered: (1) electron containment transport and controlled removal; and (2) first-order H{sup {minus}} beam steering. For electron containment, various magnetic, geometric and electrode biasing configurations are analyzed. A kinetic description for the negative ions and electrons is employed with self-consistent fields obtained from a steady-state solution to Poisson`s equation. Guiding center electron trajectories are used when the gyroradius is sufficiently small. The magnetic fields used to control the transport of the electrons and the asymmetric sheath produced by the gyrating electrons steer the ion beam. Scenarios for correcting this steering by split acceleration and focusing electrodes will be considered in some detail.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC05-96OR22464
- OSTI ID:
- 554842
- Report Number(s):
- ORNL/CP-95176; CONF-970958-; ON: DE98000798; TRN: 98:008865
- Resource Relation:
- Conference: 7. international conference on ion sources, Taormina (Italy), 7-13 Sep 1997; Other Information: PBD: [1997]
- Country of Publication:
- United States
- Language:
- English
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