Articles you may be interested inOptimization of closed ion source for a high-sensitivity residual gas analyzer J. Vac. Sci. Technol. A 32, 021603 (2014); 10.1116/1.4835635Size-selected cluster beam source based on radio frequency magnetron plasma sputtering and gas condensation Rev. Sci. Instrum. 76, 045103 (2005); 10.1063/1.1869332Investigation and reduction of spurious peaks caused by electron-stimulated desorption and outgassing by means of a grid heating method in a hot-cathode quadrupole residual gas analyzer Monitoring of gas composition for processes in the mTorr range is not possible with a conventional residual gas analyzer ͑RGA͒ unless a pressure reduction pumping system is used. A miniature sensor, having dimensions compatible with the mean-free path of gas molecules can operate directly at mTorr pressures while being less expensive and more compact than a conventional apparatus. This article describes a quadrupole RGA which is scaled down by a factor of 7 to operate at pressures up to 10 mTorr. This sensor requires different construction methods and drive electronics than a traditional RGA. A unique ion source with high output has been developed. The small sensor has resolution characteristics very similar to standard size models but sensitivity is reduced in proportion to the ratio of cross-sectional area for each quadrupole r 0 . Response is linear to the mTorr range and a correction method for gas scattering, based on pressure measured by a total pressure gauge included in the ion source design, extends the linear response to 10 mTorr.