ION SOURCES AND METHODS OF OPERATING AN ELECTROMAGNET OF AN ION SOURCE

摘要

Ion sources and methods of operating an electromagnet of an ion source for generating an ion beam with a controllable ion current density distribution. The ion source (10) includes a discharge chamber (16) and an electromagnet (42; 42a-d) adapted to generate a magnetic field (75) for changing a plasma density distribution inside the discharge chamber (16). The methods may include generating plasma (17) in the discharge space (24), generating and shaping a magnetic field (75) in the discharge space (24) by applying a current to an electromagnet (42; 42a-d) that is effective to define the plasma density distribution, extracting an ion beam (15) from the plasma (17), measuring a distribution profile for the ion beam density, and comparing the actual distribution profile with a desired distribution profile for the ion beam density. Based upon the comparison, the current applied to the electromagnet (42; 42a-d) may be adjusted to modify magnetic field (75) the magnetic field in the discharge space and, thereby, alter the plasma density distribution.