US 4,712,042 AGranted

Variable frequency RFQ linear accelerator

AssigneeAccSys Technology, Inc.

InventorRobert W. Hamm

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Abstract

A variable frequency RFQ linear accelerator has a sequence of variable inductance coils connected at intervals along the electrode vanes, such that each coil together with the corresponding section of the vanes forms an LC resonant circuit having a resonant frequency equal to the operating frequency of the accelerator. The variable inductance coils are each comprised of a helical bifilar coil, with each filament of a given coil being connected to one pair of vane electrodes on opposite sides of the beam axis, and a movable shorting bar is provided for each bifilar coil to vary the inductance. The helical bifilar coils in adjacent sections are disposed on opposite sides of the beam axis, the axes of the coils on either side being parallel to the beam axis and mutually coincident. Drive shafts extend along these axes through the wall of the vacuum vessel, with control rods extending radially outward to each of the shorting bars, and a ganging mechanism is provided to control all of the shorting bars so that the LC circuits all maintain the same resonant frequency. The power supply is connected to the vane electrodes through a capacitive impedance. Mode switches are further provided at the ends of the bifilar inductance coils to avoid interfering resonances from the sections of the coils beyond the shorting bars.

Claims54

Dependent claims

A variable frequency RFQ linear accelerator for accelerating, focusing or bunching a beam of charged particles, comprising:

an evacuated vessel through which said beam of charged particles travels:
an even-numbered plurality of elongated electrodes, supported within said vessel in parallel relation to the trajectory of said beam of charged particles, said elecrodes being disposed azimuthally around said trajectory, said electrodes further having a structrue such that they produce an RFQ electric field useful for accelerating, focusing or bunching said beam of charged particles;
power supply means connected to said electrodes for supply radio-frequency elecrical power thereto, such that said electrodes are caused to generate said RFQ elecctric field by said power supply means;
variable inductance means having an inductance which may be varied over a substantial range, said variable inductance means being electrically communicative with said electrodes, such that said variable inductance means and said electrodes form an LC resonant circuit which oscillates at the frequency desired for said RFQ electric field, and said frequency may be varied by varying the inductance of said variable inductance means;
and
inductance control means connected to said variable inductance means such that the inductance of said variable inductance means may be controlled from the exterior of said evacuated vessel.

3 more elements

Dependencies are inferred from the claim text.