Search Results (3 total)

We report the first high-gradient studies of a millimeter-wave accelerator, employing for the first time a planar dielectric accelerator, powered by means of a 0.5-A, 300-MeV, 11.424-GHz drive electron beam, synchronous at the 8th harmonic, 91.392 GHz. Embedded in a ring-resonator circuit within the electron beam line vacuum, this structure was operated at 20 MeV/m, with a circulating power of 200 kW, for 2×10⁵ pulses, with no sign of breakdown, dielectric charging, or other deleterious high-gradient phenomena. We also present the first measurement of the quadrupolar content of an accelerating mode.

There are three requirements in making a traveling wave accelerator: longitudinal electric field, synchronization, and confinement. We present and analyze a conceptually new kind of charged particle accelerator, making use of a photonic band gap lattice for field confinement near the beam axis, and employing dielectric material to produce a speed of light synchronous longitudinal electric field. An example structure design is presented. We also discuss nonlinear effect and other configurations without higher order dipole modes. Parallel scheme and fabrication are presented.

When charged particles pass through a metal pipe, they are accompanied by an image current on the metal surface. With intense short bunches passing near or even into the metal surface, the peak image current density can be very high. This current may result in substantial temperature rise on the surface, especially in high peak current, multibunch operation. In this paper, we derive an explicit formula for the surface temperature rise due to this previously unrecognized pulsed heating effect and show that this effect dominates the proposed linear coherent light source collimator spoiler and wire scanner heating. Without proper account, it can result in component and instrument failures. The result also applies to optical transition radiation screens, profile screens, wire scanners, exit windows, and targets, which the beam crosses.