The Coherent X-ray Imaging (CXI) instrument at the Linac Coherent Light Source (LCLS)

The Linac Coherent Light Source (LCLS) became the first ever operational hard x-ray free-electron laser in 2009. It will operate as a user facility capable of delivering unique research opportunities in multiple fields of science. The LCLS and the LCLS Ultrafast Science Instruments (LUSI) construction projects are developing instruments designed to make full use of the capabilities afforded by the LCLS beam. One such instrument is being designed to utilize the LCLS coherent beam to image with high resolution any sub-micron object. This instrument is called the Coherent X-ray Imaging (CXI) instrument. This instrument will provide a flexible optical system capable of tailoring key beam parameters for the users. A suite of shot-to-shot diagnostics will also be provided to characterize the beam on every pulse. The provided instrumentation will include multi-purpose sample environments, sample delivery and a custom detector capable of collecting two-dimensional (2D) data at 120 Hz. In this paper, the LCLS will be briefly introduced, as well as the technique of coherent x-ray diffractive imaging (CXDI). A few examples of scientific opportunities arising from use of the CXI instrument will be described. Finally, the conceptual layout of the instrument will be presented, together with a description of the key requirements for the overall system and of specific devices required.