Large scale light source facilities such as synchrotrons and X-ray free electron lasers (XFELs) are used across the breadth of scientific applications from helping to develop new energy storage materials to understanding viruses and aiding the development of vaccines. The demands of making faster measurements with high fluxes of X-rays has driven the development of new readout electronics and supported the adoption of direct detection materials. Driven by the upgrade to “3rd generation” synchrotrons, Si based photon counting detectors have been used on synchrotrons since the mid-2000s [1] with high-Z semiconductor options, such as CdTe, following over the next decade. In parallel, similar technologies were in development for medical-CT, but the certification requirements and barriers to entry in the medial field meant it was not until the 2020s that the first photon-counting detector CT systems reached the clinic [2].

Whereas the requirement of medical CT detectors to measure hard X-rays up to a flux of 109 photon/mm2/s at a resolution of 0.3-0.5mm is unlike to change, the synchrotron detector technology is being pushed further. Spatial resolutions less than 0.1mm are already commonplace and the advent of 4th generation synchrotrons is pushing the flux requirements up to 1012 photons/mm2/s. In parallel, XFELs which deliver very intense femto-second X-ray pulse are moving to continuous repetition rates in the MHz range which will require X-ray detectors to operate at similarly high fluxes and small pixel sizes.

Currently, the best candidate detector material for these applications is CdZnTe. It has the benefit of high X-ray stopping power, low leakage current, good electron charge transport properties, is available with fine pixelation and is compatible with some standard interconnection techniques [3]. However, CdZnTe is melt grown in 3-inch boules that limit the single die size and has limited hole transport properties that may ultimately limit the operating flux. The rapid development of Perovskite and similar detector materials have demonstrated the potential of these materials as hard X-ray detectors [4]. The challenges and opportunities that these new materials may bring to the scientific X-ray detector community will be discussed.

Whilst the ~70 light source facilities around the world may not represent the largest volume detector market, they have the benefit of being research facilities that can support the development and advancement of new detectors materials and readout technology to push the boundaries of X-ray detection.