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College Park, Maryland      June 6 - 10 , 2004

WP58: Second Generation Neutron Residual Stress Mapping Facility at ORNL

C. R. Hubbard, M.C. Wright, S. Spooner, E. A. Payzant, S. Craig, A. Stoica (Oak Ridge National Laboratory)

The replacement of the beryllium reflector at the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL) presented an opportunity to make major upgrades of beam tubes, shutters, shielding, neutron optics and instrumentation. The upgrade of the Neutron Residual Stess mapping Facility (NRSF) at HFIR is one of the major instrument upgrades taking advantage of this special opportunity. The NRSF upgrade aims to return to operation an improved world class strain mapping and research instrument at HFIR, a high flux steady state reactor, and reintegrating it into the Residual Stress User Center suite of instruments used to study residual stress and materials behavior using neutron diffraction as well as laboratory and synchrotron x-ray diffraction.

The upgrades of NRSF aim to greatly improve the systemís capabilities and create a 2nd generation strain mapping facility. The upgrades include utilizing: (a) the new larger and higher flux beam at HB-2; (b) a new multiwafer Si, doubly focusing, two crystal monochromator which yields a choice of wavelengths (from 0.145 nm to 0.227 nm) and supports horizontal bending of the monochromator to achieve optimal focusing; (c) two new very stable high precision goniometers, one of which is capable of quite large specimens while the other will enable strain tensor and highly textured specimen studies; and (d) and an array of seven 40 x 100 mm active area 1-D position sensitive detectors. The flux on specimen is predicted to be of the order of 108 neutrons/cm2/sec. Estimates of the various gains indicate that approximately a 10-fold improvement in strain measurement capability will be achieved.

As of March 1st we have initiated radiological tests of the shielding and expect in April and May to complete the installation and launch commissioning of the new facility. User access to this instrument is via the High Temperature Materials Laboratory User Program ( http://html.ornl.gov/ ). The results of monochromator tests, calibration of the instrument, and initial performance tests will be highlighted.

Research sponsored by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of FreedomCAR and Vehicle Technologies, as part of the High Temperature Materials Laboratory User Program, Oak Ridge National Laboratory, managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract number DE-AC05-00OR22725.

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