Diffraction physics3/15/2023 ![]() Finally, a crystalline undulator was produced using sandblasting and tested using γ-ray diffraction at the ILL. Moreover, the method allowed curved samples to be obtained free of any additional material. In particular, the experiment showed that the crystalline quality of the bulk was preserved. A good agreement with the dynamical theory of diffraction was observed. The curvature of the machined samples was also tested using γ-ray diffraction at the Institut Laue–Langevin (ILL), Grenoble, France. Their curvature was verified using interferometric profilometry, showing a deformation in agreement with the Stoney formalism. Several samples were manufactured and bent using the sandblasting method at the Sensor and Semiconductor Laboratory of Ferrara, Italy. A sandblasted bent crystal can also be used as an optical element for steering charged particles in accelerator beamlines. It is shown that a sandblasted crystal can be used as an X-ray optical element for astrophysical or medical applications. This procedure permits the fabrication of homogeneously curved crystals in a fast and economical way. It is demonstrated that the amorphized layer behaves as a thin compressive film, causing the curvature of the substrate. The method is based on a sandblasting process capable of producing an amorphized layer on the substrate. We therefore conclude that such self-standing crystals are good candidates as Laue lens components for astrophysics applications.Ī technique to obtain self-standing curved crystals has been developed. A careful analysis of the experimental data highlighted that the samples feature large energy bandpass, wide geometrical acceptance for incoming hard X-rays, and high diffraction efficiency. Finally, the samples were tested exploiting hard X-ray diffraction at the ID11 facility of the European Synchrotron Radiation Facility (ESRF) in Grenoble, France. The manufactured samples were characterised via optical interferometry, and showed a fairly uniform curvature. This proved to be a relatively low cost method for crystal bending, suitable for mass production. ![]() The crystals were bent through the application of a carbon fibre composite. In particular, two bent crystals featuring a thickness of 5 mm, made of Si and Ge respectively, were produced at the Sensor and Semiconductor Laboratory in Ferrara, Italy. The curvature of the crystals is a key factor to enhance diffraction efficiency and energy bandpass for such an optic. for optic to focus hard X-rays in the 100–1000 keV energy range. In this paper we report progresses in the realization of self-standing bent crystals, which are suitable as optical elements for Laue lenses, i.e. The latter case is more difficult but can be approached by more sophisticated theories such as that of Takagi and Taupin. The results are analytical in the case of a constant strain gradient and are otherwise described by simulations which can be compared to the experimental results. The diffraction by the former is handled using extensions of the dynamical theory of diffraction by perfect crystals using ray tracing. They may be nearly perfect with small strains and/or individual lattice defects faults or they may be highly deformed with large strains and a high density of defects. The main features of the diffraction by a perfect crystal are briefly reviewed: total reflection and Darwin width associated with the Bragg gap, standing waves, anomalous absorption, ray tracing, plane-wave and spherical-wave Pendellösung, polarization properties. The limitations of the geometrical theory are discussed and the concept of extinction introduced. The main theories of diffraction are briefly described and their more important results compared.
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