Abstract: Process for increasing the density and improving the homogeneity of Chevrel phase powders and Chevrel phase wire obtained using said process. Chevrel phase powers are compounds of lead, mobydenum, and sulfur. Metallic additives in the range of 0.5% to 20% by weight are introduced in the Chevrel phase powders by a physical or chemical process. The melting temperature of the metallic additives is lower than the synthesis temperature of the Chevrel phase powders so as to increase the homogeneity. The wires obtained using this process are capable of generating high magnetic fields.

Abstract: The apparatus described basically includes a vessel (10) which has a horizontal transparent window (11) and contains an index liquid (12). An optical fiber (13) is mounted in this vessel perpendicular to the window (11). Light (14) is launched and focused by a condenser (15) onto fiber (13). The light cone of aperture angle (2.beta.) due to the guided and leaky modes is eliminated using an annular mirror (16) that reflects the remaining portion of the aperture light cone (2.alpha.) escaping laterally from the fiber. This light reflected by the mirror (16) is focused by an annular condenser (18) and reflected onto a detector (20) by a flat mirror (19) with a hole in the center. Measuring the amount of light received by the detector (20) allows the refractive index of the fiber to be determined.