High-resolution and high-intensity neutron diffractometer with linear position-sensitive detector

The characteristics of a neutron diffractometer using a He-3 one-dimensional position-sensitive detector (PSD) with delay line readout, a 200 (length) x 100 (height) mm(2) active window and 2.5 mm spatial resolution have been studied and compared with those of the High-Resolution Powder Diffractometer (HRPD) of KAERI with 32 He-3 conventional tube (circle divide 50 mm) detectors and Soller collimators (10') before detectors. For the sample to PSD distance R = 1200 mm, the PSD subtends 8degrees angle of 2theta and provides the resolution and the peak-to-background ratio close to that for HRPD. Time for scanning (with the same statistics) of a 0-160degrees interval is about 1.6 times longer and the multi-PSD system providing efficiency about 10 times higher than HRPD is proposed. Because of the small angle subtended by the PSD, the parasitic peaks from the sample environment are eliminated and operation without an oscillating radial collimator is possible. Additionally, the proposed diffractometer has an advantage for small samples. (C) 2003 Elsevier B.V. All rights reserved.