Spectral X-ray phase contrast imaging with a CdTe photon-counting detector

摘要

The present study focuses on the implementation of two X-ray phase contrast imaging (XPCI) techniques: free-space propagation (FSP) and single mask edge illumination (SM-EI) with a microfocus polychromatic X-ray source and a Timepix3 photon-counting detector with a CdTe sensor. This detector offers high spatial resolution, high detection efficiency and it is able to simultaneously record information about Time-over-Threshold (ToT) and Time-of-Arrival (ToA) for each X-ray photon. All these features play a key role in enabling an improvement of XPCI image quality, especially through spectral analysis, since it is possible to measure the energy of each incident X-ray photon. Measurements of phase contrast and contrast-to-noise ratio (CNR) are presented for different energy bins within the typical spectrum of soft X-ray imaging. It is shown that a significant enhancement of XPCI image quality can be obtained, for both implemented techniques, by performing pixel clustering to correct for charge sharing and by introducing some degree of energy-weighting.