Abstract:
The neutron powder diffractometer, recently installed at the IPEN-CNEN/SP IEA-R1 3.5 MW research reactor, is equipped with a position sensitive detector (PSD). A focusing Si monochromator and a rotating-oscillating collimator (ROC) were also installed in the new instrument. At a take-off angle of 84ｰ, chosen for the monochromator, the following wavelengths can be attained: 1.111, 1.399, 1.667 and 2.191 Angstroms. The ROC, installed at the entrance to the detector shield, eliminates parasitic scattering from furnace or cryorefrigerator heat shields in the vicinity of the sample. It also makes the PSD less sensitive to ambient background. In this work, several neutron powder patterns, obtained with different compounds, will be presented in order to give an idea of the quality of the new instrument. Use of the IPEN-CNEN/SP PSD neutron diffractometer is open to the scientific and technological communities from Brazil and other Latin-American countries.
The authors acknowledge the financial support given by Funda鈬o de Amparo ・Pesquisa do Estado de S縊 Paulo (FAPESP), under project no. 95/05173-0.