Abstract: A system has been developed for adsorbing gases at high vacuum in a closed area. The system utilizes large surface clean anodized metal surfaces at low temperatures to adsorb the gases. The large surface clean anodized metal is referred to as a metal sponge. The metal sponge generates or maintains the high vacuum by increasing the available active cryosorbing surface area.

Abstract: An apparatus for measuring a level of a cryogenic fluid in a cryostat includes a semiconductor pressure sensor mounted at the end of an elongated vertically disposed tube. The semiconductor pressure sensor is located at the bottom of the tube and is sealed in the bottom of the tube by a polymeric insulating material. The upper end of the tube is provided with a vent hole which communicates vapor pressure within the cryostat to the interior of the tube. The pressure sensor outputs an electrical signal in accordance with the differential pressure exerted on a semiconductor element of the pressure sensor from opposite sides by the vapor pressure within the tube and the fluid pressure outside the tube.