Gotthard-II is a charge-integrating silicon microstrip detector developed for energy-dispersive experiments and X-ray photon beam diagnostics at the European X-ray Free-Electron Laser (EuXFEL). Its one-dimensional geometry, featuring fewer readout channels than pixel detectors, and its fast readout capability make it the only segmented detector able to perform experiments at a 4.5 MHz frame rate while capturing all 2700 X-ray pulses in a bunch train produced by the EuXFEL machine. The Gotthard-II detector was tested for single-photon sensitivity and dynamic range, meeting all specifications. In addition to FEL applications operating at a 4.5 MHz frame rate in burst mode, the detector supports continuous acquisition at up to 400 kHz and counting mode at ≤4.5 MHz for synchrotron applications. Experimental tests with standard samples using X-ray diffraction and X-ray emission spectroscopy were conducted at several beamlines of the Swiss Light Source (SLS) and EuXFEL. The measurement results were compared with those obtained using established detectors at these beamlines, demonstrating the performance of the detector in energy-dispersive experiments.
