Parametric X-ray Radiation (PXR) is well known as intense, tunable and quasi-monochromatic x-ray source. From the very first work of Ter-Mikaelian, who proposed the interaction phenomenon for Parametric X-rays, many theoretical and experimental studies have investigated the characteristics of such a novel x-ray source. Within the framework of classical electrodynamics, we have thoroughly studied the physical implications of electrons moving through a medium at relativistic speed and then developed an analytical model of x-ray diffraction based on the PXR phenomenon. The model has been used to obtain information on the characteristics of PXR diffracted beam in terms of x-ray intensity, energy spectrum and angular distribution. Preliminary results on the diagnostic potential of PXR have shown that, at a distance from the crystal which produces a size of the x-ray field useful for an imaging application, the photon yield of PXR is higher than that produced by a conventional x-ray tube, provided that a similar electron current is available. Based on the analytical model of PXR generated by a relativistic electron beam in crystals, in this contribution we discuss the possible application to x-ray breast imaging. Since the Parametric X-ray Radiation depends on the characteristics of electron beam, crystal target, and geometric configuration, an optimization study has been carried out to evaluate the performance of this novel x-ray source. Several crystals have been taken into account both in Bragg and Laue geometry and their relative yield has been compared. We also investigated the irradiation field by considering real experimental conditions that broaden theoretical PXR photon distribution. To this aim the effects of multiple scattering and divergence of electron beam have been included in the analytical model and the characteristics of the x-ray field are presented in terms of beam uniformity and energy gradient. Finally, the effects of electron interaction within the crystal target on the spatial resolution properties of PXR source are also discussed.
Application of Parametric X-ray Radiation to Diagnostic Radiology: A Theoretical Study
DI DOMENICO, Giovanni;CARDARELLI, Paolo;GAMBACCINI, Mauro;MARZIANI, Michele;TAIBI, Angelo
2010
Abstract
Parametric X-ray Radiation (PXR) is well known as intense, tunable and quasi-monochromatic x-ray source. From the very first work of Ter-Mikaelian, who proposed the interaction phenomenon for Parametric X-rays, many theoretical and experimental studies have investigated the characteristics of such a novel x-ray source. Within the framework of classical electrodynamics, we have thoroughly studied the physical implications of electrons moving through a medium at relativistic speed and then developed an analytical model of x-ray diffraction based on the PXR phenomenon. The model has been used to obtain information on the characteristics of PXR diffracted beam in terms of x-ray intensity, energy spectrum and angular distribution. Preliminary results on the diagnostic potential of PXR have shown that, at a distance from the crystal which produces a size of the x-ray field useful for an imaging application, the photon yield of PXR is higher than that produced by a conventional x-ray tube, provided that a similar electron current is available. Based on the analytical model of PXR generated by a relativistic electron beam in crystals, in this contribution we discuss the possible application to x-ray breast imaging. Since the Parametric X-ray Radiation depends on the characteristics of electron beam, crystal target, and geometric configuration, an optimization study has been carried out to evaluate the performance of this novel x-ray source. Several crystals have been taken into account both in Bragg and Laue geometry and their relative yield has been compared. We also investigated the irradiation field by considering real experimental conditions that broaden theoretical PXR photon distribution. To this aim the effects of multiple scattering and divergence of electron beam have been included in the analytical model and the characteristics of the x-ray field are presented in terms of beam uniformity and energy gradient. Finally, the effects of electron interaction within the crystal target on the spatial resolution properties of PXR source are also discussed.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
