The nucleon facility NA at PSI

The Nucleon Area (NA) at the Paul-Scherrer-Institut (PSI) was built as a multi-purpose facility for experiments with polarized or unpolarized protons or neutrons. For both kinds of nucleons the available energy ranges from about 100 MeV up to a maximum of 590 MeV. This article presents technical details of the layout of the nucleon beams and areas, the experimental arrangements, and the equipment employed. An experimental program on neutron-proton scattering is presently carried out using the NA facility at PSI. We put special emphasis on the polarized neutron beam and its use to measure the neutron-proton elastic scattering.