The end-use performance of a paperboard depends on its quality. The major properties of a good quality paperboard include consistency in the expected ratio between the thickness of the core and the coating layers, and the uniformity in the coating layer. Measurement systems using X-rays to monitor these properties could assist the paperboard industries to assure the quality of their products in a non-destructive and automatic manner.   Phase Contrast X-ray Imaging (PCXI) has been used successfully to look inside a wide range of objects using synchrotron radiation sources. Recent advancements in the grating interferometer based PCXI technique enables high quality phase-contrast and dark-field images to be obtained using conventional X-ray tubes. The darkfield images map the scattering inhomogeneities inside objects and is very sensitive to micro-structures, and thus, can reveal useful information about the object’s inner structures, such as, the fibre structures inside paperboards.   In this thesis, methods, using spectroscopic X-ray imaging and PCXI technique have been demonstrated to measure paperboard quality. The thicknesses of the core and the coating layers on a paperboard with the coating layer on only one side can be measured using spectroscopic X-ray imaging technique. However, the limited spectral and spatial resolution offered by the measurement system being used led to the measured thicknesses of the layers being lower than their actual thicknesses in the paperboard sample. Suggestions have been made in relation to overcoming these limitations and to enhance the performance of the method.   The dark-field signals from paperboard samples with different quality indices are analysed. The isotropic and the anisotropic scattering coefficients for all of the samples have been calculated. Based on the correlation between the isotropic coefficients and the quality indices of the paperboards, suggestions have been made for paperboard quality measurements.

The new generation of X-ray free electron laser sources are capable of producing light beams with billion times higher peak brilliance than that of the best conventional X-ray sources. This advancement motivates the scientific community to push forward the detector technology to its limit, in order to de-sign photon detectors which can cope with the extreme flux generated by the free electron laser sources. Sophisticated ex-periments like deciphering the atomic details of viruses, filming chemical reactions or investigating the extreme states of matter require detectors with high frame rate, good spatial resolution, high dynamic range and large active sensor area. The PERCI-VAL monolithic active pixel sensor is being developed by an international group of scientists in collaboration to meet the aforementioned detector requirements within the energy rangeof 250 eV to 1 keV, with a quantum efficiency above 90%. In this doctoral research work, Monte Carlo algorithm based Geant4 and finite element method based Synopsys SentaurusTCAD toolkits have been used to simulate, respectively, theX-ray energy deposition and the charge sharing in PERCIVAL. Energydeposition per pixel and charge sharing between adjacent pixels at different energies have been investigated and presented. Novel methods for industrial and environmental applications of some commercially available X-ray detectors have been demonstrated. Quality inspection of paperboards by resolving the layer thicknesses and by investigating orientation of the cellulose fibres have been performed using spectroscopic and phase-contrast X-ray imaging. It was found that, using phase-contrast imaging it is possible to set burn-out like quality index on paperboards non-destructively. X-ray fluoroscopic measurements have been conducted in order to detect Cr inwater. This method can be used to detect Cr and other toxic elements in leachate in landfills and other waste dumping sites.