Indirect X-ray detectors with single-photon sensitivity

Abstract

The new generation of synchrotron light sources are pushing X-ray detectors to their limits. Very demanding conditions with unprecedented flux and higher operating energies now require high-performance X-ray detectors combining sensitivity, efficiency and scalability. Over the years, hybrid pixel detectors have supplemented indirect detectors based on scintillation, with undeniable advantages. Such detectors based on silicon are, however, rather expensive to produce and are no more satisfying in terms of X-ray stopping power when targeting energies above 20 keV. An indirect detector with single X-ray photon sensitivity therefore offers promising opportunities for applications operating over a wide range of energies and fluxes. In this work, the performances of such an approach are investigated with state-of-the-art elements: a commercial sCMOS camera with fiber-optics plate coupling and a Gd2O2S:Tb powder-based scintillator. A simple method is presented for evaluation of the single X-ray photon detection limit and single X-ray sensitivity is demonstrated with the studied detector above 20 keV. Geant4 simulations also provide insight to better define the limiting factors. Finally, guidelines are provided for future R&D in the design and assembly of an innovative detector combining advantages of direct and indirect detection schemes.

Advances in Perovskite Nanocrystals and Nanocomposites for Scintillation Applications

“…In the case of scintillating NCs or nanocomposites with low density, the photoelectric peak is difficult to observe and a relative method is used for the LY measurement, which can follow three alternative approaches: ( i ) the RL intensity corrected for the fraction of absorbed X-rays evaluated by monitoring the variation of the response of a reference scintillator, ( ii ) a side-by-side comparison of the RL intensity with a reference scintillator in identical geometrical conditions, and ( iii ) the RL intensity corrected for the X-ray mass attenuation coefficient and the sample thickness, which overestimates the LY by neglecting the self-absorption and the light outcoupling factor. In Table we report LY values of PNC-based scintillators produced and processed following various synthesis and fabrication approaches, in comparison to crystal and plastic scintillators.…”