Abstract: A method for controlling a particle acceleration energy in a radio-frequency quadrupole accelerator, the method being particularly adapted for ion implantation in the process of manufacturing semiconductor devices, wherein the particle acceleration energy is varied without the necessity of changing the resonant frequency of the RFQ accelerator so that the final energy of the particles has a plurality of distinct energy having a lower value than the designed voltage.

Abstract: A control system for controlling a radio frequency resonant cavity type linear accelerator so as to be power-supplied always at a resonance frequency of a resonat cavity constituting the accelerator. The system consists essentially of a signal pick-up coil inserted in the resonat cavity, a voltage-controlled oscillator assembly, a phase detector for detecting a phase difference between a signal picked up from the cavity by the signal pick-up coil and an output from the voltage-controlled oscillator assembly. An output from the phase detector controls the voltage-controlled oscillator assembly so as to make it oscillate at a frequency equal to a resonance frequency of the resonant cavity.

Abstract: In a multipole linear accelerator such as of a quadrupole type, fine positional adjustment of the tip portions of the electrodes constituting the multipole structure can be made with electric contact kept substantially unaffected between the electrodes and the cavity drum in which the electrodes are mounted. Each of the electrodes are provided with a series of contact plates on both sides of the root portion of the electrode over the whole length thereof. Each of the contact plates, which are held to the root portion of the electrode by means of an adjusting screw bolt, slantwise bridges the root portion of the electrode and the inner surface of the cavity drum with elastic contact pieces interposed.