Adapting the TRIGA Pitesti Q-space focusing crystal neutron diffractometer for stress determinations

During the last decade new principles for the design of high-resolution configurations for crystal neutron diffractometry have been developed leading to the concept of Q-space high-resolution configuration which proved to be an alternative to the existing conventional configuration. The characteristics of such a focusing configuration are the use of open beam geometry, use of the bent crystals in asymmetric reflection as monochromators and the rotation of the sample during the diffraction pattern raise, to fulfil the focusing conditions. High-resolution is obtained with no collimators by controlling the curvature and reflectivity of bent monochromators. This paper aims to clarify in which conditions such a Q-space focusing configuration, particularly that existing at INR Pitesti, can be used for stress determinations. Taking account of the characteristics of such measurements, it is quite obvious that the sample cannot be put in focusing position appearing a limitation of the dimension of the sample region for which stress determinations are made, if we want still to have a reasonable good resolution. (authors)