First dielectric wakefield experiments at Daresbury Laboratory

The first dielectric wakefield acceleration (DWA) experiments have been conducted at the CLARA/VELA test facility at Daresbury Laboratory, UK. The DWA structures were of planar geometry with variable gap and dielectric thicknesses ranging from 0.025 to 0.2 mm. The facility, in its current state, provided electron bunches with up to 100 pC bunch charge, and variable 0.2-2.0 ps bunch lengths at the beam energy of 35 MeV. All major wakefield effects have been observed including energy modulation in longer bunches, energy dechirping, and transverse streaking and focussing. With a modest bunch charge of ~ 50 pC, a decelerating field of ~ 8 MV/m was measured. Using this variable gap planar structure, we have also demonstrated generation of continuously tunable narrowband THz. A summary of experimental results and near future developments are presented.