Compact High-Resolution Multi-GeV Electron Spectrometer for PW-Laser-Driven Plasma Accelerators and Approximate Trajectory Method for Spectrum Analysis

For the past decade, laser-plasma accelerators (LPAs) of millimeter to centimeter lengths have provided compact sources of nearly mono-energetic, highly directional electron bunches, with energies as high as 1 GeV. With the advent of petawatt scale lasers, these accelerators are now poised to go well beyond 1 GeV energies. In contrast to large-scale accelerator facilities, these LPA's will be compact devices, requiring compact electron spectrometers adapted to the unique properties of the LPA electron bunches. We report on a compact high-resolution spectrometer adapted to these conditions.