A cylindrical magnetron ionisation gauge

Abstract

this report describes a new vacuum gauge in the form of an inverted cylindrical magnetron. This gauge is useful in the pressure range 10 −4mm. Hg. to 10 −8mm. Hg. The main advantages over existing gauges are a much higher current output at a given pressure and the elimination of elaborate devices for emission stabilisation. It is very well adapted for use in a bridge-type leak detector using butane as a probe gas and a leak detector using these tubes has indicated leaks of less than 10 −6 lusec. The best figure claimed for the mass spectrometer is 10 −7 lusec, so the sensitivities of the two leak detectors are of the same order.