A 10 Kelvin cryogenic system for separating gases

Cryogenic traps are used as a simple medium to transport gases in vacuum systems, as a means to separate gases in mixtures, or to clean gases from contamination. Different components ask for different temperature traps. When more than two gases have to be separated from a gas mixture, it may be a complicated and time-consuming operation because several stable cold traps need to be aligned. The poster presents the development of a system that allows to cool down a gas mixture to 10 K via a built-in oven, including a fine temperature controller. The fractions of the gas mixture can be released depending on their chemical composition and their vapour pressure. The cryogenic system uses helium in a closed system. It turns the mixture of gases into a liquid or a solid, and operates completely free of additional chemical products and gases can be released free of isotopic effects. The system operates in a very safe mode and can easily be connected to measurement apparatus such as a gas chromatograph or a mass spectrometer. The unit was initially developed for chemical analysis of a mixture of perfluoroalkanes (CF4, C2F6, C3F8, etc) but could also be used for isotope amount ratio measurements of gas mixtures or for low volume preparation of high purity gases from a gas mixture. (authors)