Neutron energy analysis by silicon prisms

Neutron energy analysing allows to measure at di fferent wavelengths at the same time thus avoiding losses due to monochromatization. We built and tested a refractive energy analysing device made from small prisms, where losses only occur due to the attenuation in the material. We measured the refraction and the transmission of MgF2 and Si prisms at the V14 reflectometer in Berlin at 4.9 Angstroem to check their applicability. The experimentally determined linear attenuation coe cients are 0.055 cm 1 for the MgF2 and 0.03 cm 1 for the Si prisms. An energy analyser consisting of silicon prism layers was measured at the EROS reflectometer at the LLB in a white neutron beam. The useful wavelength band was 2.4 to 7.6 Angstroem . At 6.7 Angstroem a wavelength resolution of 5 and a transmission of 53 were achieved. The surface roughness of the prisms could be determined to be 0.011 0.006 de