Optimizing area-backlighter performance in a difficult geometry

It is relatively easy to predict backlighter performance when few beams intercept a simple flat target and backlight an optically thin object. However, when faced with a thick target, noncooperating geometry, and multiple objects in the path of the laser beams, it becomes a challenge to find the optimum arrangement to satisfy all these conditions. On Omega, we came up with a unique solution, using more than one coaxial foil to optimize, not only the pointing and focusing, but also the uniformity and flux of x rays on the target using as many of the laser beams as possible. We will describe the method used, the geometry used, and compare the prediction and the measurement.