We present a combined theoretical and experimental study of Silicon Carbide–based sensors for X-ray white-beam monitoring and diagnostics in synchrotron facilities. Two complementary sensor architectures have been analysed: hole-type sensors, offering mature operation and high spatial sensitivity, and blade-type sensors, providing enhanced robustness under large beam missteers and suited as upstream “first-element” X-ray diagnostics before front-end diaphragms. Each architecture shows distinct advantages and limitations, meeting different monitoring requirements along the beamline. These sensors, produced and commercialized by SenSiC GmbH, were tested across several international facilities, including Diamond Light Source, the Swiss Light Source (SLS 2.0), SOLEIL, and HEPS, demonstrating stable operation, accurate position sensitivity, and reliability under high thermal and photon-flux loads. Theoretical modeling, supported by detailed spectral and power-absorption simulations, shows excellent agreement with experimental results. The long-term objective of this work is to establish a unified class of reliable SiC-based diagnostics that can act as a bridge between the accelerator and beamline communities, providing synchronized upstream (electron-beam) and downstream (X-ray beam) information to enhance beam stability, optimization, and control across the full "photon-production chain".

Beam stability is essential in beamline experiments, where vibrations, thermal drifts, misalignment of the optical components (mirrors, monochromators), beam energy variations and electronic noise can influence the beam position leading to non-negligible drifts, degrading the quality of the measurements, as observed during X-Ray Absorption Spectroscopy (XAS) experiments. To address these issues, STLab s.r.l. in collaboration with SenSiC GmbH is developing a compact real-time feedback system embedding a PID controller directly inside its custom readout electronics, the PCR4 picoammeter. The unit provides four 24-bit channels at 10 kHz and two 16-bit ultra-low-latency DACs enabling control-loop frequencies up to 1 kHz. Tests at the GALAXIES beamline (SOLEIL Synchrotron) using two in-line 10-µm SiC XBPMs, one for feedback and one at the sample position, demonstrated compensation of a 50 µm vertical drift during XAS, achieving stabilization within 1 µm around the setpoint. The dual-function PCR4, acting as both readout and control system, offers a compact and scalable approach to beam stabilization. Future developments aim to extend the control bandwidth toward 10 kHz and integrate the system into the machine using white-beam X-ray monitors, enabling faster control loops synchronized with the electron beam.