ULTRAHIGH VACUUM IN SMALL GLASS SYSTEMS

Abstract

Techniques and apparatus used in these laboratories for the production of ultrahigh vacuum in glass systems of 1 to 5 liters volume are described. Constructional details of the gauges, ionization pumps, and control circuits are given. No diffusion pumps are used with this method, thus avoiding contamination from pump fluids and the need for refrigerated vapor traps. Pressures in the range 5 × 10 −11 to 10 −10 torr are routinely obtained in Pyrex glass systems by minimizing the outgassing rate of the components and by pumping with small ionization pumps.