Fig. 3: Scan of the target size.

a, b Proton cutoff energy Ecut at 0° and 30°, respectively. The results of a total of 58 shots are plotted and the error bars indicate the standard deviation. The dashed lines were obtained from 2D PIC simulations, and a factor of 0.6 was multiplied to correct the dimensional effect. c, d Measured and simulated electron spectra at 20° from various targets, respectively. The shaded regions in c represent the standard errors of 10 (planar) and 5 (D = 50 μm) laser shots.