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U.S. Department of Energy
Office of Scientific and Technical Information

Electron energy recovery system for negative ion sources

Patent ·
OSTI ID:864205
An electron energy recovery system for negative ion sources is provided. The system, employs crossed electric and magnetic fields to separate the electrons from ions as they are extracted from a negative ion source plasma generator and before the ions are accelerated to their full kinetic energy. With the electric and magnetic fields oriented 90.degree. to each other, the electrons are separated from the plasma and remain at approximately the electrical potential of the generator in which they were generated. The electrons migrate from the ion beam path in a precessing motion out of the ion accelerating field region into an electron recovery region provided by a specially designed electron collector electrode. The electron collector electrode is uniformly spaced from a surface of the ion generator which is transverse to the direction of migration of the electrons and the two surfaces are contoured in a matching relationship which departs from a planar configuration to provide an electric field component in the recovery region which is parallel to the magnetic field thereby forcing the electrons to be directed into and collected by the electron collector electrode. The collector electrode is maintained at a potential slightly positive with respect to the ion generator so that the electrons are collected at a small fraction of the full accelerating supply voltage energy.
Research Organization:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN
DOE Contract Number:
W-7405-ENG-26
Assignee:
United States of America as represented by United States (Washington, DC)
Patent Number(s):
US 4329586
OSTI ID:
864205
Country of Publication:
United States
Language:
English