Charge distribution of elements in the ion beam produced from an rf-spark ion source

The ion yield distribution of elements with respect to charge in the beam produced from an rf-spark ion source has been studied for eight matrices. The thermochemical behaviour of the elements as well as the features of the matrix plasma are found to be the key factors. It is shown that the consideration of charge distribution helps to improve the precision of the spark source mass spectrometric analysis. It is argued that, in the course of the development of the matrix plasma, the vaporised particles in the sparking zone undergo element-sensitive multiple ionization. It is further concluded that, during the process of expansion of the plasma into the vacuum, the ions of different elements suffer different rates of recombination. Thus, the ionization energy available per particle controls the charge distribution of the elements in the plasma while the abundances of ions according to charge in the beam are regulated by the average energy available per particle and different recombination rates.