The Dielectric Resonator Wakefield Accelerator

Abstract

We report preliminary studies of a three-channel, rectangular, high gradient dielectric wakefield accelerator element, which, unlike the collinear cylindrical dielectric wakefield device, does not suffer from low transformer ratio and may offer relief from the beam breakup instability. When configured as a resonator (DWR), it can be driven by a series of modest-charge drive bunches. This rectangular mode-locked resonator consists of three channels lined with low-loss dielectric slabs: the central wider channel is the drive bunch channel, whereas two adjacent narrow channels are used to accelerate electron and/or positron bunches; this provides a favorable transformer ratio. At the moment when, after reflecting from the resonator exit, the wakefield returns to the resonator entrance, the next bunch is injected into the resonator entrance. The length of the resonator is also chosen to be a multiple of half the desired wakefield wavelength. The rectangular geometry permits superposition of harmonics of wakefields in the resonator. The short length of the device and its planar configuration should allow management of beam breakup, and a lengthy drive bunch train can be dynamically stabilized by using a series of DWR units rotated about the z-axis in 90 increments.

Modernization and Adjustment of the Microwave Power Control System of the “Almaz-2m” Accelerator

“…In a structure with collinear motion of bunches, where the drive and accelerated bunch move along the same path, the transformer ratio, defined as the ratio of the maximum increase in the energy of the electrons of the accelerated beam to the maximum energy loss of the particles of the leading beam [8,9], cannot exceed 2. To increase it, it was proposed to use charge profiling inside a single bunch [10], profiling a sequence of bunches (ramped bunch train) [11][12][13][14], or using multi-zone multi-channel dielectric structures [15][16][17][18]. In order to obtain profiling a sequence of bunches, precise synchronization of separated units of the "Almaz-2M" accelerator is necessary.…”

Approximate method for electromagnetic analysis of a dielectric-loaded coupler used in accelerating structures

“…Nowadays, dielectric-loaded waveguides have broad applications in electron devices such as power extractors and electron beam accelerators [1][2][3][4][5]. Because of their compact size, light weight and ease of fabrication, they have received much attention in high power terahertz and X-ray sources used in industrial, medical, and military applications [6][7][8][9].…”