Speaker
Description
Over the last two decades, Hybrid Photon-Counting (HPC) pixel detectors have revolutionised and enabled a wide range of techniques at synchrotron light sources. These achievements are driven by their high frame rates, large dynamic range, radiation hardness, high DQE, and no noise associated with the readout operation [1]. However, the impact of HPC detectors has so far been largely confined to the tender and hard X-ray regimes, while the soft X-ray range remains comparatively inaccessible. DECTRIS lowest energy detectors are those from the PILATUS series, which achieve energy thresholds as low as 1.6 keV [2,3].
DECTRIS is actively pushing the lower energy boundary. This contribution presents ongoing R&D efforts at DECTRIS to extend X-ray photon-counting capabilities towards 1 keV for small-pixel sizes of 75 µm2. Several complementary approaches are being pursued, including optimization of existing detector designs, exploration of novel sensor concepts with internal gain such as Low-Gain Avalanche Diodes (LGADs)—building on the work reported in [4,5]—and the development of a new low-noise application-specific integrated circuit (ASIC).
Characterization results from multiple prototype systems will be presented, based on both in-house and synchrotron beamtime measurements. In addition, the first performance results in ptychography applications at SoftiMAX (MAX IV) and experiments at SIRIUS (SOLEIL) will be shown.
References:
[1] Förster, A., Brandstetter, S. & Schulze-Briese, C. Transforming X-ray detection with hybrid photon counting detectors. Philos. Trans. R. Soc. A 377, 20180241 (2019).
[2] Wernecke, Jan, et al. "Characterization of an in-vacuum PILATUS 1M detector." Synchrotron Radiation 21.3 (2014): 529-536.
[3] O. Chellai et al.; Calibration of a versatile multi-energy soft X-ray diagnostic for WEST long pulse plasmas. Rev. Sci. Instrum. 1 April 2021; 92 (4): 043509. https://doi.org/10.1063/5.0043456
[4] Zhang, J., et al. “Development of LGAD sensors with a thin entrance window for soft X-ray detection.” Journal of Instrumentation 17.11 (2022): C11011.
[5] Baruffaldi, F., Bergamaschi, A., Boscardin, M. et al. Single-photon counting pixel detector for soft X-rays. Commun Phys 8, 321 (2025). https://doi.org/10.1038/s42005-025-02240-9
We acknowledge MAX IV and SoftiMAX, in particular K.Thanell, I. Beinik, and J.Schwenke, for close collaboration, enabling calibration, characterization, and application results. We also acknowledge SOLEIL SIRIUS, especially M. Chauvin, A. Dawiec, M. Andrä, K. Paton, P. Fontaine, and G. Ciatto, for beamline access, characterization, and XRD measurements.