NOVEL HIGH-TEMPERATURE, HIGH-VACUUM, ALL-METAL SAMPLE CELLS FOR MICROCALORIMETRIC MEASUREMENTS OF SOLIDS

The design of a novel microcalorimetric sample cell which allows rapid transfer of heat from the sample to the cell wall is described. The s olid sample is dispersed around the internal walls of the cell. Since the thermopiles of the microcalorimeter are in contact with the outer surface of the cell, the new design of the cell allows rapid recording of the heat generated by the sample. The robust all-metal cell allows in situ sample activation under conditions of high vacuum and at temp eratures up to 500 degrees C. The dispersion of the sample avoids any ''deep bed'' effects where gas may not be able to diffuse freely to th e surface of all of the sample, which may be the case when a thick lay er or plug of the sample is used. The cell enables faster acquisition of heat data and minimizes effects of self-heating of the sample. A si mple tool, which assists the introduction of the solid sample into the cell and a compact resistor-element, which fits inside the cell for c alibration, are described. (C) 1997 American Institute of Physics.