I. Ionita 1), B. Grabcev 2), S. Todireanu 2), G. Popescu 5), F. Constantin 3), M. Mincu 1), E. Anghel 1), V. Shvetsov 4), A. Datcu 1)

Abstract:
The SANS configuration with mechanical monochromator has significantly increased luminosity while the spatial extension of the instrument is quite reasonable. Tacking account that TRIGA reactor existing at INR Pitesti is a medium flux reactor and that the available dimension for the SANS instrument is severely limited by the dimensions of the room where the instrument has to be installed, this experimental configuration has been chosen as the most suited for the situation existing in our institute. For usual collimation values of about 30 minutes, and for an inclination angle of the monochromator axis of about 2-3 degrees, Dl/l is about 20-30%, i.e. quite reasonable value. The sample width may be fixed between 10 mm and 20 mm. The minimum value of the scattering vector is while the maximal value is . The relative error is . In the case of our SANS instrument a monochromatic neutron beam with is produced by a mechanical velocity selector with helical slots. The distance between sample and detectors plane is (5.2 m).