ABSTRACT
This chapter describes devices constructed to produce and detect ultra-cold neutron (UCN) with well-defined velocity characteristics and discusses their various applications. The instruments can be roughly divided into two main classes: those that define or measure a single UCN velocity component—one-dimensional UCN spectrometers—and those that determine the total UCN kinetic energy—UCN monochromators. The axial (vertical) velocity component of UCN generated in the converter and successfully passing the chopper gradually decreases as they rise against gravity in the guide tube. Their transverse velocity component remains constant providing that the reflection at the guide surfaces between the chopper and detector can be considered to be specular. Several multiple mirror systems have been designed which can simultaneously eliminate magnification and position chromatism to various orders. Such mirror systems have been used in all of the UCN microscopes so far designed.
