Narrow-band acceleration of gold ions to GeV energies from ultra-thin foils

Experimental results

Figure 1a shows a schematic of the experimental setup at Vulcan, the details of which can be found in the Methods section. Figure 1e, f, g shows the Au ion spectra obtained using Thomson parabola spectrometers (TPS) directed along three observation lines, from the interaction with a 15 nm (black) and a 30 nm (red) thick Au target. The Au traces for similar charge states (typically between 36–55+ for the 15 nm target, and 44–58+ for the 30 nm target) had an unavoidable overlap at energies above a few MeV/n, as can be seen in the traces shown in Fig. 1b–d. The…