Chemical Method to Increase Extreme Ultraviolet Microchannel-Plate Quantum Efficiency. II. Analysis and Optimization

Enhancement of the extreme ultraviolet quantum detection efficiency (QDE) of microchannel plate (MCP) detectors by use of a wet chemical method is examined. It is shown that the chemical process of ion exchange, in addition to physical processes that increase surface roughness and decrease surface density, augments the secondary electron emission coefficient, which in turn increases the quantum detection efficiency of the input MCP. The method has been demonstrated with nitric acid, acetic acid, or water used as the active reactant. By monitoring and optimizing the ion-exchange process, we achieved a 2.6 -4.4 increase in the MCP QDE from 1216 to 304 A, respectively, with an absolute QDE of approximately 50% at 304 A.