Possibility for ultra-bright electron beam acceleration in dielectric wakefield accelerators

Design of an emittance exchanger for production of special shapes of the electron beam current

“…Similar to the drive bunch shaping, some optimization of the witness beam can be used to satisfy the additional requirements on uniformity of the accelerating gradient within the witness bunch. We have shown that proper timing between the DT drive beam and the witness bunch together with a custom trapezoidal shape of the witness bunch can be used to reduce the witness beam energy spread, and, in doing so, preserve the beam brightness [17]. Figure 1 shows the proposed time profiles of the drive and accelerated bunches for a possible proof-of-principal experiment.…”

“…If one can make the wakefield to be longitudinally constant along the bunch it will result in no induced energy spread within the bunch, leading to an extraordinary condition of preserving the main beam brightness while providing high gradient acceleration. We have realized that it is possible for an accelerated beam in a DWA to achieve the needed small energy spread if the longitudinal witness bunch profile is properly customized [17].…”

Suppressing parasitic effects in a long dielectric wakefield accelerator

“…Due to the small diameter it can be inserted inside of the beam focusing magnets and, in particular, inside of the quadrupole FODO lattice. The small energy spread inside of the main bunch can be achieved by proper shaping of the main bunch itself [3] through the self-wake. The wakefield acting on the bunch is a superposition of the self-wakefield and the wakefield from the drive bunch, the last one usually being much stronger.…”

“…A high transformer ratio wakefield can be realized with a custom (double triangular) shape of the drive bunch which experiences almost uniform deceleration [2]. In addition, by proper shaping and timing of a witness bunch one can minimize the growth of its energy spread [3]. However, for the high acceleration efficiency, proper bunch shapes, timing, and small beam width must be preserved over the whole length of the DWA, which may be as long as hundreds of meters.…”

Adaptive electron beam shaping using a photoemission gun and spatial light modulator

“…The 3D distribution has been shown to have a significant impact on the emittance evolution of a space charge dominated beam [1][2][3][4][5], and is significant for various other applications such as conventional or cold atom electron sources for electron diffraction [6,7], or next generation acceleration techniques [8,9]. Furthermore, during high current photoinjector beam operation, the uniformity of the photocathode can be damaged by various phenomena including ion back-bombardment, high voltage discharge, or increased vacuum pressure, and may therefore change the electron density from a given laser shape as a function of time.…”