Saturation Effect of Secondary Emission Coefficient in MCP-based Multipliers

A strong dependence of the time-of-flight mass spectrum on the signal value was found when ions were detected by an MCP-based secondary electron multiplier. Ions were created by the photoionization of atoms generated during laser metal evaporation. The results indicate that this effect is associated with a saturation of the detector sensitivity, which is especially strong when recording translationally cold ions. This effect can lead to large distortions of the mass spectrum when time-of-flight mass spectrometry is used in combination with molecular beam sampling.