METHODS AND APPARATUS FOR CONTROLLING CONTAMINANT DEPOSITION ON A DYNODE ELECTRON-EMMISSIVE SURFACE

Components of scientific analytical equipment, and particularly to methods for extending the operational lifetime or otherwise improving the performance of dynodes used in electron multipliers. The method includes: (i) increasing the secondary electron yield of a dynode and/or (ii) decreasing the rate of degradation of electron yield of a dynode, by exposing a dynode electron-emissive surface to an electron flux under conditions causing electron-impact induced removal of a contaminant deposited on the dynode electron-emissive surface. The conditions may be selected such that the electron-mediated removal is enhanced relative to a contaminant deposition process so as to provide a net decrease in the rate of contaminant deposition and/or a decrease in the amount of contaminant present on the dynode electron-emissive surface.