Pixelated Energy-dispersive Photon-counting Detector Calibration with X-ray Diffraction

X-ray photon counting detector (PCD) technology has brought great energy-resolved imaging ability into medical imaging applications such as spectral CT, X-ray fluorescence (XRF) and X-ray diffraction (XRD). However, practical factors such as statistical charge fluctuation, charge sharing and K-escape effect deforms detected spectrums. Accurate PCD energy response calibration is critical for spectrum restoration. Metal powder XRF is the most commonly used calibration method for PCD energy response in laboratories. However, XRF is limited by few discrete incident energies and relatively narrow energy range of easily-accessed metal materials. In this work, we proposed a new method for PCD energy response calibration based on crystal XRD. Crystal XRD can generate continuously adjustable monochromatic X-rays at different diffraction angles, which is suitable for energy response calibration task. In this work, we use crystal XRD for an energy-dispersive PCD (EDPCD) calibration. EDPCD detects full spectrum data at each detector pixel. It plays an important role in XRD imaging (XRDI) and XRD tomography (XRDT). We verified the EDPCD calibration result with metal powder XRF experiments. Results suggest the accuracy of the proposed method.