Liquid sample delivery controls at LCLS

The Linac Coherent Light Source (LCLS) at SLAC National Accelerator Laboratory is a pioneering X-ray free-electron laser that provides researchers with the ability to investigate matter at atomic and molecular scales with unprecedented temporal and spatial resolution. Its applications span a wide range of scientific disciplines, including materials science, chemistry, biology, and physics. A vital aspect of conducting successful experiments at LCLS is the precise delivery of samples into the X-ray beam. Depending on the nature of the sample—whether liquid, gas, or solid—various delivery systems are employed to ensure accurate positioning, high repetition rates, and minimal sample waste. In this talk, I will present an overview of the control systems developed to support liquid sample delivery for the chemRIXS instrument. I will focus on two advanced systems that have significantly enhanced experimental capabilities. The first is a recirculating liquid sheet jet system that enables the generation of tunable liquid sheets with minimal sample volume, making it ideal for experiments with limited material availability. The second is a Droplet-on-Demand (DoD) robot designed for high-throughput pump–probe studies. This system allows precise sample placement, low sample consumption, and efficient mixing, which are essential for time-resolved measurements.