Generation and Applications of Parametric X-ray Radiation by Using an Electron LINAC

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When a relativistic electron is passing through a single crystal, it. generates X-rays to the direction corresponding to the Bragg condition. The generated X-rays are new type and named as parametric X-rays (PXR). Parametric X-rays constitute a tunable source (by rotating the crystal relative to the direction of the incident electron beam) of monochromatic and very directional X-rays. As one of the purpose of this project, we attempted to confirm a high-quality tunable monochromatic hard X-ray radiation field. The conditions of constructing this X-ray field were determined by the classical and quantum field theory and experiments using HOKUDAI 45 MeV Electron LINAC.For an electron beam incident on a Si single crystal at an angle φ = 10°to the (100) surface, PXR was detected at the point of 3 m distant from the target at an angle θ=20°. The 15〜 30 keV hard X-ray fields were constructed. For the energy and angular distributions of PXR, the theoretical results were in agreement with the experiments. The tunability and monochromaticy of PXR were confirmed.Another purpose of this project was applications by using the tunable monochromaticy of PXR. The K-edge absorption characteristics of Nb, Zr and Mo were measured. The experimental results were agreed quite well with the theoretical results on the Web: http://physics.nis.gov/PhysRefData/cover.html. In synchrotron radiation a high amount of monochromaticy can be achieved by passing the radiation through a crystalline Bragg diffractor. As synchrotron radiation is very intense, however, the huge loss of intensity suffered by this Bragg diffraction can sometimes be partially accepted. PXR can be sufficiently useful and tactful without a huge scale accelerator.