Increasing sensitivity of the ion analyzer on the base of the MI-1305 mass spectrometer

A design of a modernized ion-analyzer collector unit is described. The unit is based on the MI-1305 mass-spectrometer designed to study element and chemical compositions of solids by using the method of secondary ion-ion emission. A channel electron multiplier (CEM) employed in an ion current recording circuit in con unction with a movable collector permits the measurement of ion currents in the range from 10-10 to 10-18 A. Specific features of CEM operation in an ion analyzer are considered. It is pointed out that to provide stable operation of the CEM the current at the multiplier input shall not exceed 10-12 A. To increase the CEM useful life it is necessary to use at the input a changeable plate made of Cu-Be alloy