Introducing the CANDOR polychromatic reflectometer

The new CANDOR neutron reflectometer at the NIST Center for Neutron Research marries the advantages of time-of-flight polychromatic reflectometers, such as those commonly employed at pulsed neutron sources, to the high time-averaged flux of a reactor neutron source. CANDOR’s unique energy dispersive detector, currently comprising 108 individual wavelength-sensitive neutron detectors operating at over 90% efficiency, allows simultaneous detection of cold neutrons in the 4 Å to 6 Å wavelength range. In this talk, I will describe the instrument features of CANDOR and compare its performance to that of conventional reflectometers. In particular, CANDOR’s 20-fold speed increase over NIST’s monochromatic reflectometers enables faster measurement, smaller sample sizes, and improved sensitivity to small effects. These features will be demonstrated in combination with CANDOR’s full neutron polarization capabilities for magnetic thin film samples. For solid/liquid interfaces, CANDOR’s measurement speed increase and intrinsic background rejection allows routine measurement to at least twice the scattering vector, and hence resolution, of conventional measurements.