VARIABLE FREQUENCY RFQ LINEAR ACCELERATOR

摘要

A variable frequency RFQ linear accelerator, has a sequence of variable inductance coils (9, 10) connected at intervals along the electric vanes (1, 2, 3, 4), to form an LC resonant circuit in relation to the operating frequency of the accelerator. The variable inductance coil (9, 10) is comprised of a helical bifilar coil (9, 10), with each filament being connected to one pair of vane electrodes (1, 2, 3, 4), and a movable shorting bar (21), to vary the inductance. The helical bifilar coils (9, 10) in adjacent sections are disposed on opposite sides of the beam axis, and their axes are parallel to the beam axis and mutually coincident. Drive shafts (19) extend along these axes, with control rods (20) extending radially outward to each of the shorting bars (21), and a ganging mechanism providing control for all the shorting bars (21) to maintain the same resonant frequency. The vane electrodes (1, 2, 3, 4) are energized through a capacitive impedance (54, 55). Mode switches, at the ends of the bifilar inductance coils, alleviate interfering resonances from the sections of the coils (9, 10) beyond the shorting bars (21).