Neutron Sciences Directorate

PIONEER is a time-of-flight, single-crystal diffractometer optimized for studying small-volume samples (< 1mm³) in a range of sample environments, including high/low temperature, magnetic field, and pressure. The instrument will provide world-leading capabilities by reducing sample volume requirements for single-crystal neutron diffraction experiments by more than one order of magnitude, allowing detailed atomic-scale structural characterization of materials at the earliest stages of discovery when large crystals are typically unavailable. PIONEER will be capable of measuring tiny crystals (~ 0.001 mm³) and ultra-thin epitaxial films (~10 nm thicknesses  x 25 mm² area). It will also provide a polarized beam option to study weak magnetic scattering signals and support a high-resolution mode to probe large unit cells up to 200 Å.

PIONEER will leverage the unique Second Target Station source characteristics of high cold-neutron flux and a small beam footprint with the latest advances in neutron optics, neutron spin manipulation, instrument design, and computational techniques to enable rapid data collection despite small-volume samples and weak signals. Time-of-flight resolution will significantly reduce reflection overlap and lower the background noise. With a 4-Å wavelength band and 4.4-sr detector coverage, PIONEER will measure a broad reciprocal space at a single sample rotation. The 800-mm sample-to-detector distance will provide flexibility in using various sample environments.