Four-Circle Neutron Diffractometer FONDER at JRR-3: Quantitative Reciprocal-Space Measurements in Structural Physics

The Four-circle Off-centered Neutron DiffractometER (FONDER), which is a four-circle neutron diffractometer used to study structures under various sample environments with single crystals, has been revealed to be an efficient instrument not only for the measurement of crystal and magnetic structural analyses, but also for the quantitative measurements of superlattice reflections and diffuse scattering. Here, the performance of FONDER and the comparison of its use with the curved two-dimensional position sensitive detector (C-2DPSD) are described, and studies using FONDER for the structural analyses of trehalose dihydrate, the multiferroic compound RMn₂O₅, and short-range magnetic ordering in Pt–Mn alloys are reviewed. The prospects for combining the technique with X-ray or time-of-flight (TOF) Laue diffraction techniques are discussed.