The beamline was to be for “Magnetic and High Resolution Diffraction”. An 18-month design study was funded and begun in March 1992: the evolution of the design considerations are described in Paul et al. Rev. Sci. Instr. 66, 1741-5, (1995)
. After advice from a review panel chaired by Denis McWhan, the two mirror design, which would have maximized the wave-vector resolution attainable, was rejected in favour of simpler optics consisting of a water cooled constant exit double-crystal monochromator, followed by a toroidal mirror, which provided a focal spot (1:1 focussing) at the centre of a multi-axis diffractometer. Provision was also made for unfocussed monochromatic and white beam operation.