Figure 15

(a) Measured 2^nd IVAC trace of the He⁺ (b) 2^nd IVAC trace of the Ar²⁺ ion signal as a fuction of the delay of the XUV-XUV delay line. The gray circles correspond to the raw data recorded, the moving averages of the raw data taken over 10 points are represented by the red circles. The black curves is a Gaussian fit over the averaged points. The temporal width of the Gaussian fit corresponds to a pulse duration of 670 ± 80 as and 650 ± 80, for He⁺ and Ar²⁺ respectively.