DETERMINATION OF THE EFFICIENCY OF CHANNEL ELECTRON MULTIPLIERS BY THE PULSE METHOD

A method for measuring the efficiency of electron detection by channel electron multipliers (CEMs) is described. In this method, an accelera ting voltage is applied to the cathode of the electron source (a three -electrode gun) in the form of short (similar to 100 ns) rectangular p ulses with a low repetition rate (that is much lower then the upper li miting value of the particular CEM type). For the rest of the time, th e electron flux is closed and does not arrive at the CEM input. Therew ith, the constant current of the gun may be increased by two to three orders of magnitude as compared to the maximum value for a particular type of GEM. This allows one to avoid the difficulties involved in mea surements of low currents. Using this method in combination with an el ectrostatic analyzer having known characteristics makes it possible to not only measure the electron-detection efficiency over a wide energy range (0.005-15 keV), but also to carry out the certification of trit ium sources of electrons that are used in the calibration of spectrome tric equipment.