High-Resolution Neutron Powder Diffractometer (HRNPD)

Available at Brookhaven

This new user facility offers resolution in neutron powder diffraction patterns exceeding that of many X-ray diffractometers in the high angle region. The HRNPD has an instrumental profile which is smooth and narrow and nearly symmetric. To combine high resolution with high intensity, the unit features a 25-element "Venetian blind" monochromator design and 64 ³He detectors.

As is shown by the 420 reflection of CeO₂, above, the FWHM of the instrumental profile is no more than 0.15° at 103° (2 Θ) with 11'-11'-5' collimators in place. This corresponds to (Δd)/d in the 10^-4 range. Many studies dependent on details of the reflection profiles (e.g., slight splitting from subtle phase changes, correct separation of the contributions from different phases, microstructure studies via details of "line" broadening) are made possible by the instrument.

Half of the instrument's time is available to general users on a competing proposal basis. One may gain access to the instrument either as a general user or through collaboration with a Participating Research Team (PRT) member. For a General User proposal form, write to Ms Rae Greenberg, HFBR User Programs Administrator, Physics Dept., Brookhaven National Laboratory, Upton, NY 11973, USA. For a list of PRT members and their addresses, contact Prof. R. A. Young, PRT Chairman for the HRNPD, School of Physics, Georgia Institute of Technology, Atlanta, GA 30332, USA.