Currents on MDT end plugs

A sample of MDT tubes was irradiated in the CERN X5 facility to study their aging behaviour. Part of these tubes were subjected to a glow discharge cleaning (sputtering) with reversed high voltage up to 1660 mC/cm. Current and Ohmic resistance measurements on these tubes gave the same null result as for non-irradiated tubes. The inner plastic surface of one end plug was analysed through the XPS technique. No traces of aluminium were found.