A Method for the Study of Correlated Events in Time-of-Flight Mass-Spectrometry and its Application to Fission-Fragment Induced Desorption

For experiments on fission-fragment induced desorption the detection o f significant correlations between desorbed ions has been reported [1]. In this paper the method for the detection and quantitative description o f these correlations will be described. The statistics o f the desorption-process leads to equations for mass-line intensities o f ion spectra. Using a t ime-to-amplitude-converter for flight-time measurements these intensities depend on interdependences o f different ions desorbed b y the same fission-fragment. The equations allow the computation o f correlationcoefficients whose interdependence with desorption probabilities o f the respective ions can be shown in Venn-diagrams. Results are given and an interpretation is suggested for fission-fragment desorbed thiamine molecular and fragment ions.