Poster: POLDI: a tof-diffractometer for residual stress investigations at PSI
Authors: U. Stuhr and G. SchuckConference: 10th European Powder Diffraction Conference (EPDIC), 1st to the 4th September 2006 in Geneva, Switzerland , PDF
POLDI is a novel type of
tof-diffractometer at PSI, which is designed mainly for strain scanning
experiments. The concept of the instrument is based on multiple
overlapping neutron pulses and allows to tune the resolution and the
intensity independently. The dependence of the time-of-flight of the
neutrons on the scattering angle is used as extra information in order
to analyze the data. This concept made it possible to build a
time-of-flight diffractometer at a continuous neutron source with short
flight path, high resolution and high intensity. The best resolutions
(ΔQ/Q , FWHM) achievable are between 1.2·10-3 and 1.8·10-3. at Q = 2 Å-1 and Q = 8 Å-1,
respectively. Since the neutron beam at the sample has only a width of
3 mm the instrument is best suited for experiments with small samples
or small gauge volumes within large samples where high resolution in a
broad Q-range is required.
The principle concept and the layout of the instrument with its main components (chopper, neutron mirror and the 3He
detector in time focusing geometry) will be presented and the
performance of the instrument will be demonstrated with some
experimental results.