LEAK DETECTION IN 10-13 TORR ALUMINUM VACUUM-SYSTEMS

10 −13Tonr aluminum vacuum systems with sputter ion pumps, titanium sublimation pumps, and roughing pumps consisting of turbobacked, turbomolecular pumps have been completed. Leak detection has been accomplished by means of the buildup method of helium monitored with a quadrupole residual gas analyzer. The minimum detectable leak rate is below 2 × 10−15Torr /7s. Most leaks below IX 10−10Torr 77s were found in flange joints with aluminum A1G50 H18 gaskets. However, few leaks occurred in flange joints with aluminum A105O H24 gaskets or in feedthroughs, liquid nitrogen shrouds, aluminum alloy-stainless steel transitions, view ports, or electron beam welded parts. © 1990, American Vacuum Society. All rights reserved.