X-ray Free-Electron Lasers (XFELs) such as the European XFEL (EuXFEL) generate extremely brilliant, ultra-short X-ray pulses at megahertz repetition rates. Because the pulse energy, position, and temporal propertiesfluctuate strongly from pulse to pulse, precise, non-invasive, pulse-resolved diagnostics are essential for optimalbeam delivery and advanced experiments. This work demonstrates the use of electronic-grade single-crystalCVD (scCVD) diamond detectors in a duo-lateral electrode configuration as a high-speed, radiation-hard beam-position monitor and intensity detector for hard X-rays (> 20 keV), where conventional gas detectors loseefficiency. Two diamond detectors (different thicknesses) were tested at the Materials Imaging and Dynamics(MID) instrument of the EuXFEL. They successfully performed pulse-resolved beam position and intensitymeasurements at 2.25 MHz repetition rate. The position uncertainty was < 1 % of the beam size. Excellentagreement was observed both between the two diamond sensors and with reference detectors (gas ionizationchamber and X-ray imager). These results establish duo-lateral scCVD diamond detectors as a powerful,compact, and reliable diagnostic tool for high-repetition-rate hard X-ray FELs, enabling real-time beam-basedalignment and intra-pulse-train position feedback.
Yildiz et al. (Thu,) studied this question.