Comparison of the effects of X-ray-pulse structure and dose on different jets. (a) A water jet similar to the one shown in Figs. 4 and 5, exposed to a full train of 250 X-ray pulses at a repetition rate of 1 MHz, measured 90.1 s; after the initial pulse. (b) A thinner and faster water jet exposed to the same pulse train structure, measured 3.14 s after the initial pulse. (c) An ethanol jet also exposed to the same pulse train structure and measured at the same delay. (d) A slow water jet exposed to two FLASH pulses with a spacing of 221.5 ns. (e) A faster water jet exposed to the double-pulse, measured 50 ns after the second pulse. (f) A slow ethanol jet that barely recovers before the second X-ray pulse hits it 221.5 ns later, as measured 50 ns after the second pulse. (g) A fast ethanol jet under the same conditions. (h) A table with the experimental conditions of the jets shown in panels (a)–(g). The jets shown in (a)–(c) were formed with one particular nozzle and (d)–(g) were formed with another. A slice through an X-ray tomogram of the latter nozzle is shown in Fig. 1. The ethanol jets, especially (f) and (g), exhibit a non-symmetric gap formation where the jet explosion is directed towards the right side. The X-ray beam is incident from the left and is strongly absorbed at the surface of the jet. The energy deposition into the jet is consequently non-uniform.