Distance Detector Manometer for Measurement and Control of Liquid Helium Temperatures in Magnetic Fields

Abstract

An accurate device for measuring and controlling the pressure of a liquid helium bath is described. The device makes use of distance detectors which sense the levels of mercury in a manometer and adjust heat to the helium bath to keep the pressure constant. The device, unlike those using resistors as a sensing element, gives highly accurate control in the presence of changing magnetic fields. The manometer is also useful for general pressure measurements, giving rapid, accurate, and easily read results.