A COMBINATION COMPACT KNUDSEN CELL-MASS SPECTROMETER APPARATUS FOR ALLOY STUDIES

An unique Knudsen cell-mass inlet to a quadrupole mass-spectrometer was designed, constructed, and used to study the activities of individual components of multicomponent alloys. The compact chamber reduces the evacuation time and its design provides the good alignment and close control of all parameters necessary to obtain reproducible data in successive measurements. The ratio of the ion currents obtained from one component of an alloy and from the same component in pure form can thus be used to obtain the activity of that component in the alloy. Through effective heating and shielding, the chamber does not need water cooling when operated below 2000 K.