Periodic Reporting for period 2 - PEARL (Periodically bent crystals for crystalline undulators)
Reporting period: 2018-01-01 to 2019-12-31
Improvement in the technologies for manufacturing periodically bent crystals (PBC) of exceptional quality;
Developing techniques for high precision characterization of periodical bending by means of the highest quality X-ray diffraction imaging apparatus and beam;
Channelling experiments with CUs and the radiation detection;
Advanced algorithms and computer codes for crystalline structure modelling and optimization, in order to simulate particle propagation through media, calculate the spectral-angular distribution of the emitted radiation.
Within the PEARL project a series of CUs were manufactured at the Ferrara lab, Italy and their structural properties were characterized at the European Synchrotron Radiation Facility (ESRF) x-ray light source. A number of experiments aimed at accurate characterisation of the quality of the periodic bending in the PBCs produced by means of different technologies has been carried out at the ESRF. The bent and periodically bent crystalline samples were exposed to intensive beams of ultra-relativistic electrons and positrons at different accelerator facilities (at MAMI, SLAC, CERN). During these experiments the channeling properties of the projectiles were analysed and the radiation emitted was measured. Within the project, computational support of various experimental activities has been carried out by means of the MBN Explorer package. Channeling phenomenon and radiation emission has been studied computationally for ultra-relativistic electrons and positrons passing through Si1-xGex superlattices, periodically bent diamond crystals and in a heavier tungsten crystal. The features of the channeling process have been highlighted, the radiation spectra have been computed, discussed and the recommendation for the experimental observation of the predicted features have been formulated.