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ANNUAL REPORT SMITHSONIAN INSTITUTION, 19 64 



and much new useful knowledge of nature's physical extremes is com- 

 ing from this work. 



Many of the exploratory elforts in superpressure incorporate so- 

 called "dynamic" or explosive shock techniques in which very high 

 temperatures and pressures up to a million atmosplieres are obtained 

 for very short periods of time, usually a few millionths of a second. 

 Diamonds have been made by these processes. Alternatively, very 

 high "static" pressures, sucli as 500 kilobars, together with high 

 temperatures, may be attained at a sacrifice of reaction volume, and 

 some interesting researches are being conducted by this method. Many 

 new forms of matter are being explored at superpressures, and it is 

 clear that the final chapters to the story of superpressure have not yet 

 been written. One must expect exciting news from this source of 

 scientific exploration for many years in the future. 



The cliart in figure 3 shows some of the capabilities of different ap- 

 proaches. The "belt" apparatus developed at the General Electric Re- 

 search Laboratory, because of its unique combination of 200 kilobar 

 pressures and 3000 to 5000° K. temperatures — plus workable pressure- 

 chamber volumes — has thus far provided an excellent diamondmaking 

 method as well as the research technique with greatest versatility. 

 Superpressure research around tlie world is now concerned with such 

 subjects as the determination of the elastic constants of various mate- 



PRESSURE-TEMPERATURE AREAS ATTAINABLE 



1964 



800 r 



PRESSURE 

 (KILOBARS) 



600 



400 



200 



SHOCK 

 COMPRESSION 

 (millionths of 



a second ) 



MODIFIED 

 ANVIL 

 APPARATUS 

 (hours) 



BELT APPARATUS (hours) 



3100" 



Figure 3. — Capabilities of different approaches. 



