The single-crystal/powder diffractometer WAND² at the High-Flux-Isotope reactor
by
Zoom Webinar
The Wide Angle Neutron Diffractometer (WAND) at the High Flux Isotope Reactor (HFIR) at the Oak Ridge National Laboratory (ORNL) has been part of HFIRs instrument suite since the 1980s. In October 2017, the last phase of the planned upgrade program had begun and one of the two ever built 120 degree, 2-dimensional position sensitive detector from Brookhaven National Laboratories (BNL120) had been installed at the HB-2C beamport.The updated instrument has been named WAND² and has been back in the user program from May 2018.
WAND² is positioned as a thermal, multi-purpose, high throughput powder-/single crystal diffractometer. The instrument can use a large portion of HFIRs sample environment, allowing measurements from mK to 1500 K, magnetic fields up to 6 T and high pressures (~ 16 GPa). The large area coverage allows efficient collection of powder data in short time and is combined with the possibility to event filter to external synchronized parameters. We installed two time domains, one for slow controls with time resolution of ms and one synchronized domain with ~100ns resolution for stroboscopic measurements.
For single crystal diffraction the instruments strenght is the mapping of a large area in reciprocal space with an excellent noise to background ratio. This allows for instance the search for weak magnetic signals when the propagation vector is unknown and the mapping of diffuse scattering.
In my talk I will introduce the HFIR and the history of the WAND diffractometer. I will detail the improvements on WAND² implemented during the upgrade and review some of the challenges we encountered. I will review a selection of showcase experiments to show the performance of the new instrument.
Dr. Christian Franz
Dr. Jitae Park
