17 October 2012 An attempt to overcome diffraction limit in detectors for x-ray nanotomography
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In synchrotron set-ups with a parallel x-ray beam, the spatial resolution is fully defined by the x-ray camera performance. This is also true in some laboratory x-ray imaging and CT instruments with an object position close to the detector. Fiber optic coupling does not allow camera resolutions reaching micron and submicron range, while cameras with lens coupling demonstrate resolutions close to diffraction limit, i.e. around 0.5 microns. Considering the conversion of x-rays to light in scintillator materials as a type of fluorescence under certain excitation, it should be possible to implement a method similar to Stochastic Optical Reconstruction Microscopy (STORM) in fluorescent microscopy to overcome diffraction limit in detector resolution. Our idea to overcome diffraction limit in such detectors is as follows. Every x-ray photon produces a significant amount of optical photons emitted from one particular point inside the scintillator. A fraction of the emitted optical photons is collected by a lens and hits the detector with a spread defined by the diffraction limit. Comparing the signal spread from every individual x-ray photon with the expected pre-calculated spread function, one can find the exact positions of primary x-ray photon. Using such exact positions to create images instead of collecting all incoming optical photons allows tracking exact positions of all original emitting points of x-ray photons without influence of optical diffraction limit. It can create images with a spatial resolution significantly better than what can be achieved in conventional diffraction limited optical acquisition.
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A. Sasov, A. Sasov, "An attempt to overcome diffraction limit in detectors for x-ray nanotomography", Proc. SPIE 8506, Developments in X-Ray Tomography VIII, 85060T (17 October 2012); doi: 10.1117/12.929520; https://doi.org/10.1117/12.929520

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