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Photon-counting imaging camera for high-resolution X-ray and γ-ray applications

Hall, D. J. and Holland, A. (2011). Photon-counting imaging camera for high-resolution X-ray and γ-ray applications. Journal of Instrumentation, 6(C01022)

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Standard X-ray imaging techniques using CCDs require the integration of thousands of X-ray photons into a single image frame. Through the addition of a scintillating layer to the CCD it is possible to greatly increase the X-ray detection efficiency at high energies. Using standard imaging techniques with the inclusion of the scintillating layer does, however, leave serious limitations on the spatial resolution achievable due to the spreading of the light generated in the scintillator. The Electron-Multiplying CCD (EM-CCD) shares much of the common architecture of the standard CCD but for the inclusion of a supplementary readout register. This additional high-voltage register allows the signal electrons to be `multiplied' before reaching the readout node of the CCD, increasing the signal before any significant noise is introduced. The increase in the signal-to-noise ratio allows very low signals to be extracted above the noise floor, leading to the common use of EM-CCDs in night-vision and security applications. Through the coupling of a scintillator to an EM-CCD it is possible to resolve individual X-ray photon interactions in the scintillator above the noise floor. Without this extra gain these low signals would be lost beneath the noise floor. Using various centroiding techniques it is possible to locate the interaction position of the incident X-ray photon in the scintillator to the sub-pixel level, with measurements here at 59.5 keV giving an initial FWHM of the line spread function of 31μm. This high-resolution, hard X-ray imager has many potential applications in medical and biological imaging, where energy discrimination at a high resolution is desired. Further applications include synchrotron-based research, an area in which high-resolution imaging is essential.

Item Type: Journal Item
Copyright Holders: 2011 IOP Publishing Ltd and SISSA
Extra Information: 12th International Workshop on Radiation Imaging Detectors, July 11th–15th 2010, Robinson College, Cambridge, U.K.
Keywords: X-ray detectors; Scintillators, scintillation and light emission processes (solid, gas and liquid scintillators); Gamma camera, SPECT, PET PET/CT, coronary CT angiography (CTA); Photon detectors for UV, visible and IR photons (solid-state) (PIN diodes, APDs, Si-PMTs, CCDs, EBCCDs etc)
Academic Unit/School: Faculty of Science, Technology, Engineering and Mathematics (STEM) > Physical Sciences
Faculty of Science, Technology, Engineering and Mathematics (STEM)
Research Group: Centre for Electronic Imaging (CEI)
Item ID: 26204
Depositing User: David Hall
Date Deposited: 10 Feb 2011 16:34
Last Modified: 08 Dec 2018 01:46
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