OSIRIS (the first step). A user guide

The OSIRIS Project will explore the instrumental horizons available with the cold neutrons from a pulsed source and especially the totally new avenues available to polarised neutrons on these sources. On pulsed sources, polarisation techniques offer great potential for high resolution studies, and only lack of opportunity has left the field unexploited. On OSIRIS, the fundamentally novel methods developed on IRIS will be combined with proven and extended neutron polarising techniques. The high flux available at ISIS, coupled to the advanced design of the OSIRIS guide, will provide the means to take this field to its next evolutionary stage. By exploiting the combination of sharp pulses, white beams and cold neutrons from ISIS, high resolution measurements, both dynamic and structural, can be carried out using both unpolarised and polarised neutrons. The OSIRIS Project is an international collaboration involving India, Italy, Spain, Sweden, Switzerland and the United Kingdom. The project has three well-defined phases; phase 1: Extraction of a second cold beam guide from the IRIS beam line; phase 2: large d-spacing powder diffraction, incident beam polarised powder diffraction; phase 3: high resolution spectroscopy, spectroscopy polarisation analysis, diffraction polarisation analysis. This is the user manual for the first step of the OSIRIS project, which means that phase 2 is now almost finished, i.e. we have a high resolution large d-spacing diffractometer, but the incident beam polarisation is as of yet only used for tests. You can find more information on the Osiris web-pages at . This document is also available in an html version at that address. This document is divided into five different parts. First, this short introduction, then what you need to think about before your arrive at ISIS, thereafter, the different parts of the instrument are described, together with some examples of sample environments. Fourthly, the actual running of an experiment is dealt with, and you should read this carefully. When you understand how to write a command file to run the experiment you are ready to go. Finally, the the data reduction programmes available on OSIRIS are described. Reading the short part about syntax will save you a lot of trouble. (author)