Accessing off-Hugoniot states via multilayer ring-up targets

While laser shocks have long been used as a method for reaching high pressure states, their highly entropic nature limits the range of pressures over which a sample can be kept solid. Laser pulse shaping has been used to ramp compress samples while keeping them close to the isentrope, but this requires long laser pulses that are unavailable to most facilities or expensive pusher materials such as diamond or sapphire. We introduce a technique that uses a multilayer target with different impedance layers that result in the sample `ringing-up' to the desired pressure via a series of smaller shocks, keeping it cooler. We present data from a recent experiment performed at LCLS using this technique, allowing us to reach 170 GPa in Pb while keeping it solid.