Dependence of PXR beam performance on the operation of the pulsed electron linac

Advanced applications of parametric X-ray radiation (PXR) such as energy-dispersive X-ray absorption fine structure (DXAFS) analysis and phase-contrast imaging have been developed at the Laboratory for Electron Beam Research and Application (LEBRA) of Nihon University. To improve the electron beam quality and geometrical stability of the target crystal, the cooling-water system for the linac and the PXR target was replaced with a new one capable of more precise control. As a result, the reliability of the experimental data in PXR applications, especially in X-ray imaging, has improved. The effect of the electron beam focusing on the target crystal was also investigated. The results of X-ray imaging with a long propagation distance and measurement of the time-structure of the PXR intensity suggest that the correlation between the electron beam profile and the X-ray coherence is rather complicated. It is possible that incident electrons cause some deformation of the target crystal, becoming the dominant factor restricting the quality of intense PXR.