Control of ultralow pressures: an absolute thermodynamic manometer

摘要

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.