A compact light source providing high-flux, quasi-monochromatic, tunable X-rays in the laboratory

There is a large performance gap between conventional, electron-impact X-ray sources and synchrotron radiation sources. Electron-impact X-ray sources are compact, low to moderate cost, widely available and can have high total flux, but have limited tunability (broad spectrum bremsstrahlung plus fixed characteristic lines) and low brightness. By contrast, synchrotron radiation sources provide extremely high brightness (coherent flux), are tunable and can be monochromatized to a very high degree. However, they are very large and expensive, and typically operated as national user facilities with limited access. An Inverse Compton Scattering (ICS) X-ray source can bridge this gap by providing a narrow-band, high flux and tunable X-ray source that fits into a laboratory at a cost of a few percent of a large synchrotron facility. It works by colliding a high-power laser beam with a relativistic electron beam, in which case the backscattered photons have an energy in the X-ray regime. This paper will describe the working principle of the Lyncean Compact Light Source, a storage-ring based ICS source, its unique beam properties and recent developments that are expected to increase flux and brightness by an order of magnitude compared to earlier versions. Furthermore, it will illustrate how such an X-ray source can be the cornerstone of a local X-ray facility serving applications from diffraction and imaging to scattering and spectroscopy. An overview of demonstrated and potential applications will be provided.