HFIR Sample Environment

The HFIR Sample Environment group provides users with equipment and support for temperature, pressure, and magnetic field environments.  We are continually developing greater capabilities through internal and collaborative research and development with the scientific community.

HFIR Sample Environment Equipment — These devices are shared among all beamlines — tested and operational as of November 2, 2007.

Fig. 1. Special environment developed by ORNL scientists to study thermal-magnetic materials processing.  For the first time ever, in-situ, time-resolved measurements of the shift in the equilibrium phase transformation temperatures by the application of a high magnetic field at elevated temperatures have been accomplished using neutron diffraction methods on Fe-C binary alloys.

Developing New Sample Environment Capabilities at the HFIR
HFIR is in the midst of major upgrades in many areas, including sample environment. These upgrades are resulting from standard equipment purchases, addition of dedicated Sample Environment staff, and collaborative R&D.

Collaborative R&D

Fig. 2. Atmosphere furnace consisting of an off-the-shelf water-cooled outer jacket with ORNL-designed controls, zirconia foam liner, and MoSi2 heating elements.

ORNL scientists performed the first in-situ study of phase transformation under simultaneous high magnetic field and high temperature [1]. This proof of principle experiment began with building a high-temperature sample insert to fit inside the magnet on the WAND instrument of HFIR (fig. 1). The success of this new technique opens the door to greater understanding of the role of magnetic field on structure changes at high temperatures.

A 1700 Celsius controlled atmosphere reaction (CAR) furnace was tested off-line in October [2].  The CAR furnace will be commissioned on the HFIR WAND instrument, and will be available for use on other HFIR and SNS instruments.  Additional furnace designs are under development.

Several high pressure projects are underway.  The Sample Environment group is working with the SNAP (Spallation Neutrons And Pressure) team to develop a cryogenic cooling rig for large anvil pressure cells.  Special gas pressure cell are also being developed for use at both the HFIR and the SNS.

Progress Reports

 [1] G. M. Ludtka and J. Fernandez-Baca, Neutron Sciences Progress at Oak Ridge National Laboratory,  July 2007

[2] Original design by A. Payzant, ORNL Laboratory Directed Research and Development Award; Adapted and assembled by Sample Environment Group

Fig 3. Controlled environment sample cell for in situ neutron scattering studies of clathrate hydrates.  The image to the right shows methane hydrate forming in the upper half of the sapphire cell.