Absolute ion detection efficiencies of microchannel plates and funnel microchannel plates for multi-coincidence detection

Modern momentum imaging techniques allow for the investigation of complex molecules in the gas phase by detection of several fragment ions in coincidence. For these studies, it is of great importance that the single-particle detection efficiency is as high as possible, as the overall efficiency scales with epsilon(n), i.e., the power of the number of detected particles. Here we present measured absolute detection efficiencies for protons of several micro-channel plates (MCPs), including efficiency enhanced funnel MCPs. Furthermore, the relative detection efficiency for two-, three-, four-, and five-body fragmentation of CHBrClF has been examined. The funnel MCPs exhibit an efficiency of approximately 90%, gaining a factor of 24 (as compared to normal MCPs) in the case of a five-fold ion coincidence detection. (C) 2018 Author(s).