D33—a third small-angle neutron scattering instrument at the Institut Laue Langevin

D33 will be a third small-angle neutron scattering (SANS) instrument at the Institut Laue Langevin (ILL). Modern trends in materials science, physics and in particular nano-structured materials require that D33 should provide both high resolution and a wide dynamic range of measured scattering vector, q. In 'monochromatic' mode a velocity selector and flexible system of inter-collimation apertures will define the neutron beam. A double chopper system will enable a 'time-of-flight' (TOF) mode of operation allowing an enhanced dynamic q-range (qmax/qmin) and flexible wavelength resolution. Two large multitube detectors will extend the dynamic q-range further, giving qmax/qmin ~ 20 in the monochromatic mode and massive qmax/qmin > 1000 in the TOF mode. Beam polarization and 3He spin analysis will facilitate and expand studies of magnetism and allow a more quantitative analysis of spin incoherent samples. The position of D33 will be such as to allow high magnetic fields at the sample position.