RefloGrad/GradTOF: Neutron energy analysis for a very high-flux neutron reflectometer

Abstract

The possibility of analyzing the neutron energy coupled with a position-sensitive detector enables to perform specular reflectivity measurements on continuous neutron sources without any monochromator or chopper and thus permits intensity gains up to 20 compared to conventional reflectometers equipped with a monochromator or a chopper. In this communication, we present a spectrometer design using an energy analysis performed with a permanent magnet Stern–Gerlach device. We also propose a modified version of the spectrometer in which we combine the above setup with a high-speed chopper in order to perform classical TOF measurements (at a high repetition rate, up to 200 Hz) while still being able to use up to 30% of the full white spectrum available in the neutron guide.