Abstract: A lens surrounded by a protective chamber is focused by utilizing a magnetic field to adjust the position of the lens within the chamber. By using a magnetic field to adjust the lens position, it is not necessary to pass a mechanical device through the surface of the chamber, thereby allowing the chamber to be completely sealed to prevent contaminants from contacting the lens.

Abstract: A coaxial TWT comprises a hollow beam gun which injects a thin annular beam between multifilar helices independently supported by thin-walled dielectric sleeves. The beam is focussed by a balanced, coaxial PPM focussing assembly, causing a stable hollow beam flow. The input and output coupling helixes, and the interaction helices which form the slow-wave structure on the exterior and the interior of the hollow beam, respectively, are preferably counterwound with respect to each other to provide greater frequency bandwidth than when similarly wound. Input and output helix coupling to either the inner or the outer helix is possible.

Abstract: A tilt-angle electron gun provides a conical beam of electrons for injection into an axially aligned magnetic field of a gyrotron tube. The beam is formed by an electrostatic lens system for focussing and accelerating the electrons within a magnetically shielded region. The conical beam is substantially monoenergetic and laminar so that after injection into the magnetic field the resulting hollow beam has gyrating electrons which have an axial velocity spread sufficiently low for high efficiency gyrotron amplification.

Abstract: An axially aligned pair of spaced bucking coils energized to produce respective magnetic fields having cooperating radial components in an annular gap between the coils, and magnetic means for enhancing the radial components of the fields in the annular gap.

Abstract: A magnetic material comprising a substantially homogeneous mixture of rare earth, cobalt, and carbon elements, the percentage weight of the carbon component being in the range of about 1 percent and one-hundreth of one percent of the mixture; and a magnet made therefrom.

Abstract: A magnetic metering system comprising a transversely magnetized cylinder carrying a radially extending pointer and mounted for axial rotation between a diametrically disposed pair of biasing magnets and a diametrically disposed pair of solenoid coils, and rotation compensating means disposed between the biasing magnets and the solenoid coils for providing the cylinder and pointer with an angular movement proportional to changes in a current flowing through the solenoid coils.