Investigation of quantum efficiencies in multilayered photocathodes for microchannel plate applications

Microchannel plates (MCPs) are used in many diagnostic systems to study las er-plasma interactions. Typically the front surface of a MCP is coated with some photocathode (PC) material to convert x ray to electron. This is foll owed by electron multiplication along the microchannels. Materials such as CsI, Al, and Au have been identified as good PC materials, but the overall quantum efficiencies of these materials are low, so that electron multiplic ation along the channel has been the only path to signal amplification. Thi s approach is known to have some problems (J.D. Wiedwald, University of Cal ifornia UCRL-JC-110906, August 1992). We investigated the effect of pairing transmission PC to standard MC's and found that CsI and Au foils used in m ultilayered configuration, significantly enhance the overall quantum effici ency of the combination. The findings could lead to better MCP design and f abrication. [S0034-6748(99)60201-5].