Figure 1
The beam geometry in the xz plane. The X-ray beam direction is along the z axis, and the target gas jet flows along the y axis. When the highest peak fluence is desirable, the target gas is located at z = 0. For the single Gaussian spatial profile, the beam shape in the xz plane is shown in purple. For the double Gaussian spatial profile, the purple area is for the first Gaussian and the green area for the second Gaussian. zR1 and zR2 are the Rayleigh ranges for the first and second Gaussian profiles, respectively. Δ indicates the X-ray beam width or focal spot size, which varies along with z. The spatial fluence distribution is given in the xy plane, and a spatial profile as a function of x at y = z = 0 is shown in Fig. 2. The produced ions are collected by a detector with a slit length z0 shown at the top of the figure. |