Fig. 2.

Measured LWFA beam energy and transverse distribution without QUAPEVA. a Measurement with the spectrometer before the first screen, with corresponding energy profile and vertical divergence evaluated by superimposing the divergence in energy slices of ±1 MeV and renormalised to the charge in the given slice (solid line), and in the case of 176 ± 5 MeV (dashed line). b Electron beam transverse distribution observed on the first LANEX screen located at 64 cm from the source, without spectrometer, with corresponding horizontal and vertical profiles. c Shot-to-shot measured pointing stability and d associated statistics on the electron beam sizes