### SURFACE AREA MEASUREMENT OF GRAPHITE USING THE $gamma$-RADIATION OF Kr$sup 8$sup 5$SURFACE AREA MEASUREMENT OF GRAPHITE USING THE$gamma$-RADIATION OF Kr$sup 8$sup 5$

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 Author Clarke, J. T. Source United States Department of Energy Office of Scientific and Technical Information Content type Text Language English
 Subject Keyword CHEMISTRY ♦ ADSORPTION ♦ GAMMA RADIATION ♦ GRAIN SIZE ♦ GRAPHITE ♦ HALF-LIFE ♦ KRYPTON ♦ KRYPTON 85 ♦ MEASURED VALUES ♦ PERFORMANCE ♦ SURFACES Abstract BS>A method was developed to measure the surface area of small samples of low surface area materials using the gamma radiation of /sup 85/Kr-traced Kr to determine the amount of Kr adsorbed. Since the count rate observed is directly proportional to the Kr adsorbed, the method is much more rapid and the calculations much less time-consuming than other methods of surface area measurement. The method is applicable over a wide range of surface areas (0.001 to 10 m/sub 2//g) and to sample sizes of 0.5 g or less. The long half life of / sup 85/Kr (10.5 years) minimizes the corrections necessary for radioactive decay. The usual advantages of Kr over nitrogen (inertness, low vapor phase corrections, and spherical shape) are utilized in this method. Using this new method, it was found that the surface area of TSX nuclear graphite increased by a factor of four as the particle size was reduced from 3-mm cubes to 80-mesh. This is interpreted as indicating that the increased surface area results primarily from the opening of closed pores; this allows the surface area of graphite samples having different sizes and shapes to be estimated. (auth) ISSN 00223654 Educational Use Research Learning Resource Type Article Publisher Date 1964-04-01 Publisher Department Brookhaven National Lab., Upton, N.Y. Publisher Place United States Journal Journal of Physical Chemistry Volume Number 68 Technical Publication No. BNL-7566 Organization Brookhaven National Lab., Upton, N.Y.