Control of ultralow pressures: an absolute thermodynamic manometer.
A method of accurately manipulating the pressure of helium gas in the range P=10(-1) to 10(-20) Torr, T<5 K is presented. The method requires only a very modest apparatus and makes use of thermodynamic measurements on the 4He-Grafoil system. A calibration curve and a pressure scale for the manometer are developed which will allow convenient application in other laboratories. An experiment which utilizes the technique is briefly disscussed.
Taborek
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P
California Institute of Technology, Pasadena, California 91125, USA.
Goodstein
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