Fig. 5.

Dependency of gamma-ray generation on laser powers and wire widths. Angular distributions of gamma rays with different wire widths (A) and under different laser powers (B), where “$\times 10$” in the legend means the photon number multiplied by a factor of 10. Energy conversion efficiency of the gamma rays versus wire widths (C) and laser powers (D). (E) Energy spectra of gamma rays at 50 ${\tau }_0$ under different laser powers. In A and C, the laser power is fixed at 2.5 PW. In B, D, and E, the wire width is fixed at 0.6 $\mathrm{\mu }\mathrm{m}$.