Precise stress measurements with white synchrotron x rays

Abstract

In situ measurement of stress in polycrystalline samples forms the basis for studies of the mechanical properties of materials with very broad earth science and materials science applications. Synchrotron x rays have been used to define the local elastic strain in these samples, which in turn define stress. Experimental work to date has been carried out on a prototype detection system that provided a strain measurement precision >10(-4), which corresponds to a stress resolution >50 MPa for silicate minerals. Here we report operation of a new, permanent, energy dispersive detection system for white radiation, which has been developed at the National Synchrotron Light Source. The new system provides differential strain measurements with a precision of 3 x 10(-5) for volumes that are 50 x 50 x 500 microm(3). This gives a stress precision of about 10 MPa for silicate minerals.