A Mass Spectrometer and Gaseous Thermal Diffusion Isotope Separator

A Nier type mass spectrometer is described in which the constant deflecting magnetic field is provided by a permanent magnet. An auxiliary magnetic field parallel to the electron beam in the ion source was found necessary. A six-tube gas thermal diffusion apparatus with convective coupling for concentrating heavy carbon is described. This compact unit (seven feet high) yields concentrations of C13 up to 20 percent. The concentration was observed as a function of time and the equilibrium concentration compared with theory for several pressures.