Three Axis Crystal Spectrometer for Neutrons

Abstract

The spectrometer has been in operation since 1963 at the reactor R2 in Studsvik, mainly for measurements on phonons in metals, with emphasis on precision. Shielding is considered first, with mention of conclusions drawn from experimentation with the shielding around the beam from the reactor and with that around the detector. The mechanical design aims to achieve easy exchange or replacement of parts (particularly crystals and collimators), automatic operation, and low cost. Angles are changed and measured by means of worm gears driven by further gears from stepping motors, which permits control of the spectrometer from a programming tape in a simple and reliable manner. Some examples are given of results for aluminum.