CHRNS CANDOR - White-Beam Reflectometer

The CHNRS Chromatic Analysis Neutron Diffractometer or Reflectometer (CANDOR) instrument is a cold white beam neutron reflectometer used to study surface and interface science across a wide range of disciplines including quantum materials, magnetic multilayers, polymer films, battery heterostructures, and biological membranes. CANDOR is primarily used for specular neutron reflectometry, a technique sensitive to the depth profiles of the nuclear composition and the vector magnetization in thin films and multilayers. CANDOR offers significant advantages over traditional monochromated neutron reflectometers at reactor sources. Rather than using an extremely narrow wavelength band, as illustrated by the vertical red line in the image below, CANDOR simultaneously collects data utilizing a continuous range of neutron wavelenths from 4 Å - 6 Å. Thanks to this design, CANDOR has realized a of 20× - 30× gain factor relative to previous designs while reducing the relative noise floor. This greatly increases instrument sensitivity and enables measurements previously expected to take a week of beamtime to be done in a matter of hours.

The CHRNS CANDOR instrument is able to interpret a reflected beam with a broad wavelength dispersion thanks to the unique design of the detector arrays. Each array consists of 54 pyrolytic graphite monochromators arranges at different angles relative to the propagation direction of the reflected beam. As the beam passes through each monochromator, a relatively narrow wavelength window is diffracted into one of the 54 individual thin film neutron detectors in the side-wall of the array. As shown below, the CANDOR detector array can therefore reproduce the tight resolution function of a traditional reactor-source reflectometer while utilizing a continuous wavelength band from 4 Å - 6 Å. CANDOR currently employs 2 detector arrays, with the instrument designed to support expansion to a maximum of 26 arrays, installed in the scattering plane to increase intensity or simultaneously measure background.