High-resolution neutron diffraction monochromators

Cylindrically bent perfect crystals (BPC) as neutron monochromators/analyzers have been proved as an excellent alternative of conventional mosaic crystals providing a way how to increase luminosity and angular/energy resolution of some dedicated scattering devices installed at steady state sources [1-3].In our contribution we present the recent results of test experiments with dispersive monochromators based on a double-reflection process realized either in one cylindrically bent perfect crystals (often called as Renninger or Umweganregung effect) or by means of a sandwich using two bent perfect crystal slabs of a different cut.Depending on the bending radius of the crystal slab (or the sandwich of two slabs) the resolution / and the collimation of the monochromatized beam can be continuously adjusted in the range of 5x10 -5 -1x10 -3 .Of course, that the dispersive bent perfect crystal elements can be used also for the high-resolution analysis of the scattered beam as well as for a high precision -calibration of the TOF neutron scattering devices. Neutron diffraction investigations are in this field partially supported by the projects AV0Z10480505, GACR.