The hybrid a-Se/CMOS detector uses an a-Se photoconductor with high intrinsic spatial resolution for direct conversion of X-ray photons to electric charge. The electronic signal is then read out by a low noise CMOS active pixel sensor (APS). Without the need to first convert X-ray photons to visible light, as in indirect scintillator-based approaches, thinning of the conversion layer to minimize optical scatter is not necessary.
The direct conversion approach allows a thick conversion layer and operation at 100% fill factor for high DQE. At 35 keV, BrillianSe™ has a market leading combination of high DQE (40% at 10 cycles/mm) and a small point-spread function (PSF) (1.1 pixel). This facilitates imaging for low flux applications such as X-ray diffraction, dose sensitive protein crystallography or throughput-limited imaging of materials with and without phase-contrast.
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Parsafar, C. Scott, A. El-Falou, P. Levine, K.S. Karim, “Direct-Conversion CMOS X-Ray Imager with 5.6μm × 6.25 μm Pixels,” IEEE Electron Device Letters, 36(5), pp. 481-3, May 2015.
C.C. Scott, A. Parsafar, A. El-Falou, P. M. Levine, K.S. Karim, “High Dose Efficiency, Ultra-high Resolution Amorphous Selenium/CMOS Hybrid Digital X-ray Imager,” IEEE International Electron Devices Meeting (IEDM) Technical Digest, December 2015.
Comparing conventional and phase contrast imaging
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