Cluster size measurement of large Ar cluster ions with time of flight

Cluster size distribution is one of the most important factors in impact processes. In this study, cluster size distributions were studied with a time of flight (TOF) mass analyzer which has high mass resolution (M/ΔM=500). The average and maximum cluster size increase with the increase of the source gas pressure. The detection of time of flight ions was performed with micro channel plate (MCP) and the detection probability of MCP decreased in proportion to the velocity of the ions. As the mass of a cluster is much higher than that of a monomer, the velocity of a cluster is much slower at the same acceleration energy. Therefore, higher acceleration energy is required for the detection of large cluster ions