Abstract: The present invention provides a method for brazing a metal object to a ceramic surface defining a recess for receiving the metal object where the space between the metal object and the ceramic surface defining the recess inhibits the establishment of the oxygen depleted environment necessary to establish a reliable braze joint. The present invention includes the use of a material having a high affinity for oxygen that is positioned adjacent to the space between the metal object and the ceramic surface defining the recess and serves to pull or draw oxygen from the space to establish the oxygen depleted environment required to produce a reliable braze joint.

Abstract: The present invention provides a chop mode operated mass spectrometer that substantially reduces the effects of line signals on the operation of the mass spectrometer by admitting gas samples to the analyzer of the mass spectrometer at a frequency that is a sub-multiple of the line frequency. The signal output by the analyzer is sampled at a frequency that is a multiple of frequency at which the gas is being admitted to the analyzer and processed using a digital filter that results in the line signal being isolated from the signal or signals of interest.