Abstract
The Nanoscale Ordered Materials Diffractometer (NOMAD) is neutron time-of-flight diffractometer designed to determine pair dist
ribution functions of a wide range of materials ranging from short range ordered liquids to long range ordered crystals.
Due to a large neutron flux provided by the Spallation Neutron Source SNS and
a large detector coverage neutron count-rates exceed comparable instruments
by one to two orders of magnitude.
This is achieved while maintaining a relatively high momentum transfer
resolution of a $\delta Q/Q \sim 0.8\%$ FWHM (typical), and an achievable
$\delta Q/Q$ of 0.24\% FWHM (best).
The real space resolution is related to the maximum momentum transfer;
A maximum momentum transfer of 50\AA$^{-1}$
can be achieved routinely and the maximum momentum transfer given by the
detector configuration and the incident neutron spectrum is 125 \AA$^{-1}$.
High stability of the source and the detector allow small contrast isotope
experiments to be performed.
A detailed description of the instrument is given and the results of
experiments with standard samples are discussed.
