Abstract: An electrostatic linear accelerator includes an electrode stack comprised of primary electrodes formed or Kovar and supported by annular glass insulators having the same thermal expansion rate as the electrodes. Each glass insulator is provided with a pair of fused-in Kovar ring inserts which are bonded to the electrodes. Each electrode is designed to define a concavo-convex particle trap so that secondary charged particles generated within the accelerated beam area cannot reach the inner surface of an insulator. Each insulator has a generated inner surface profile which is so configured that the electrical field at this surface contains no significant tangential component. A spark gap trigger assembly is provided, which energizes spark gaps protecting the electrodes affected by over voltage to prevent excessive energy dissipation in the electrode stack.

Abstract: A resistor device for use with electrostatic particle accelerators includes a resistor element positioned within a tubular housing having a fixed end cap at one end thereof and a movable end cap at the other end thereof. The tubular housing, fixed end cap, and movable end cap serve as an electromagnetic field for the resistor element. Conductive disks engage opposite ends of the resistor element and concentrically position the resistor element within the tubular housing. Helical springs engage the conductive disks and the end caps to yieldably support the movable end caps and resistor element for yieldable axial movement relative to the tubular housing. An annular conducting ring is secured to the tubular housing and is spaced radially from the movable end cap and cooperates with the latter to define an annular spark gap.

Abstract: A method for increasing the efficiency of gas ionization detectors for diagnostic x-rays by matching a detector gas absorption edge with the energy level of an x-ray source to produce photons of only slightly higher energy. Sequential x-ray images using different matched gas absorption edges and x-ray source energies allows contrast information to be obtained to distinguish calcium deposits or dye from bone, for example.Specific ionization detectors useful for practicing the inventive methods are also described. One such detector uses ultrafast electronics associated with individual wires of a multiwire two dimensional proportional counter.Another detector employs a conductor backed sheet of insulating material to immobilize positive gas ions in a density distribution conforming to the x-ray image. The density distribution may subsequently be read out by electromechanical means for sensing the potential differences on the sheet.