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Description
The radiation emitted by relativistic charged particles traversing natural or artificial periodic structures has been extensively studied in recent decades. Research has demonstrated that, within such periodic media, well-known phenomena, including Parametric X-ray Radiation (PXR), Cherenkov radiation, and transition radiation undergo interference effects that can significantly influence their properties. This report presents the investigation of PXR generated by electrons with energies between 0.7 and 4 GeV as they traverse a stack of Si crystal plates. Two crystal stacks, each consisting of 11 plates, were used in the study, one with a plate thickness of approximately 200 µm and the other with 400 µm. Previous studies have demonstrated that the use of a multi-plate crystal target enhances PXR intensity as a result of interference effects. However, in these studies, separate crystal plates were used as target, potentially resulting in minor misalignments that could not be fully eliminated. In our study, we used a stack of crystal plates mounted on a single base and cut from the same crystal, ensuring significantly better alignment. In the experiment, PXR from Si(220) reflecting planes was recorded using an AMPTEK X-123SDD X-ray spectrometer equipped with a Silicon Drift Detector. The detector was positioned at an angle of 27.3° relative to the primary electron beam direction and placed 25 cm from the crystal target. The observed PXR peak energy was 13.7 keV, with FWHM of approximately 1 keV. The spectrometer’s energy resolution at this energy is 135 eV. The results indicate that increasing the electron energy leads to a reduction in PXR intensity and a corresponding narrowing of the spectral peak.