Abstract: A compact proton-beam therapy linac utilizing a linear, cascaded organization including a proton source, a radio-frequency-quadrupole (RFQ) linac coupled to the output of the source, a stepped-frequency (around 500- to around 100-MHz), low-peak-beam-current (around 100- to around 300-.mu. A) drift-tube linac (DTL) coupled to receive the output of the RFQ, and a plural-stage, low-peak-beam-current stage-switchable, side-coupled linac (SCL) coupled to the output of the DTL for producing the ultimate output proton-therapy beam.

Abstract: A radio-frequency quadrupole which includes four, extruded, identical cross-section, elongate structural components, each of which lacks any longitudinally extending plane of bilateral assembly. Joinder of these components to form a quadrupole body results in an overall axial cross-sectional configuration which has an infinite number of claims of inverted bilateral symmetry extending in all radial directions relative to the long axis of that body. Coolant-carrying boreholes extend longitudinally throughout each component with precise location and proper longitudinal-axial-parallelism.

Abstract: Apparatus for normalizing and maximizing the performance of a drift tube on the operational axis of a drift tube linac. The apparatus features drift tube positioning through structure which includes orthogonally disposed, facially complementary datum surfaces, interposed which surfaces are dimensionally stable, clamped shim structure. Also offered is independently attachable/detachable (non-dedicated in place) adjustment mechanism employable to effect adjustments in the usual post-coupler structures associated with drift tubes.

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.