Observation of multiple Bragg reflections of neutrons in bent perfect crystals

Multiple reflection effects resulting in Umweganregung or Aufhellung have been studied in elastically bent perfect silicon single-crystals which are often used for focusing monochromators or analyzers. It has been proved that under certain conditions strong multiple reflections with intensities comparable or even higher than those corresponding to single diffraction process can be excited in the deformed single crystals. This effect is documented on diffraction by cylindrically bent perfect silicon crystals.