Quality assurance of vessels for UHV applications

Vessels for UHV applications are prone to detrimental imperfections leading to either poor performance or complete failure of the system. Both design parameters as well as fabrication process affects performance of the vessels. Since UHV vessel operates at pressure less then 1 x 10-7 torr gaseous molecules can easily leak in to the system even through sub micron level path. These leaks are detrimental to system operation since they make pumping speed insufficient to maintain desired ultimate vacuum. In view of these facts UHV vessel construction demands careful design, stringent quality control during material procurements and systematic adoption of the approved fabrication process. This paper has been designed to facilitate some of the special requirement of vacuum technology and their implementation in shop so that the fabricators can improve upon their existing procedures. The subject is of greater importance in the view of the fact that there is an increasing trend in budgetary allocations throughout the world towards vacuum technology