On a possible use of multiple Bragg reflections for high-resolution monochromatization of neutrons

Multiple diffraction effects resulting in Umweganregung have been studied in cylindrically bent perfect silicon single crystals. The aim of this experiment was to find strong umweg-effects providing a highly monochromatic and collimated beam for a possible practical use. Using three different cuts of the Si crystal slabs, several very intensive umweg-effects in the thermal region from 0.1 to 0.25nm which could be used for high-resolution monochromatization namely at high-flux neutron sources have been found. The advantage of such umweg-monochromators would be their tunability through the variation of the curvature and thus the variability of the bandwidth D lambda/lambda in the range from 10(-4) to 10(-3) and collimation of the orders of minutes of arc without any employment of Soller collimators. (C) 2004 Elsevier B.V. All rights reserved.