Experimental progress towards laser acceleration of relativistic electrons with the Micro Accelerator Platform (MAP)

The Micro Accelerator Platform (MAP) is a side-coupled resonant, standing-wave dielectric laser accelerator. Its development and testing for laser acceleration of relativistic electrons has been under way for a few years. MAP has a vacuum gap formed between reflective thin film layers (Distributed Bragg Reflectors or DBRs) that generate the resonant electric field in the gap when powered with a laser of the design wavelength. The vacuum gap has a height around eight hundred nanometers while the thin film layers each are on the order of hundred nanometers thicknesses. Working with sub-micron scale structures like MAP has various challenges in both fabrication and testing. Laser acceleration testing has been taking place at SLAC NLCTA E163 using a 60 MeV electron beam together with an 800 nm wavelength laser to power the structure. Here, the transmission signature of the beam through a MAP structure is presented, and work towards detecting the acceleration signature will be discussed in light of simulation results. Discussion will incorporate progress on the whole experimental effort including challenges and iterations of fabrication, experimental setup and procedures, and subsequent data analysis.