Rapid Cycling Valve for 30-HZ Pulsed H- Ion Source

Abstract

This valve is used to reduce the gas loading on the vacuum system of a multipulsing H- ion source. It is a self-aligning chopper type. A mechanism of this construction assures the reilability required for an ion source of this nature. The reliability of this mechanism is due to the fact that the disc of the chopper is rotated at a relatively slow constant velocity and no wearing parts of the assembly are subjected to the extreme vacuum atmosphere. The entire valve assembly is very simple in construction. It is driven with a synchronous motor to keep it in step with the accelerating frequency. Vacuum integrity is maintained with the use of a ferromagnetic fluid coupling as part of the drive system. All bearings, motors, and drive mechanisms are external to the vacuum cavity.