An increase in the order of spatiotemporal focusing in the time-of-flight mass spectrometer with nonuniform field in the ion-acceleration regions

An algorithm for the calculation of electrostatic field in an arbitrary region of acceleration in the mass reflector using the criterion of an increase in the spatiotemporal focusing is presented. Nonuniform accelerating field providing spatiotemporal focusing of the third and fourth orders in the presence of uniform field in the reflector is calculated for a mass reflector with ionization on the surface of target. The effect of the size of input window of detector on the resolution in the presence of nonuniform field in (i) ion source and (ii) ion source and reflector is considered.