Output Systems for Time-Of-Flight Mass Spectrometers

Abstract

The three major types of output systems for time-of-flight mass spectrometers are described and their applications discussed. An oscilloscope output system is used to obtain quick answers with accuracy being limited to the accuracy of the oscilloscope employed For very small mass peaks, accuracy degenerates to zero. An analog output system is considered to be the most useful and versatile output system. It uses a selective gated input to measure simultaneously the areas under several mass peaks. Using this type of output, spectral patterns which are normally generated in several miscrosec can be recorded on recorders with a response of 100 cps or less. When the average number of ions per mass peak per mass spectrum is considerably less than one, a counter circuit (digital output system) can be used to totalize the ions which occur in specific mass peaks. Several mass peaks can be counted simultaneously