The Characterization Of Secondary Electron Emitters For Use In Large Area Photo‐Detectors

The Large‐Area Picosecond Photo‐Detector Project is focused on the development of large‐area systems to measure the time‐of‐arrival of relativistic particles with, ultimately, 1 pico‐second resolution, and for signals typical of Positron‐Emission Tomography (PET), a resolution of about 30 pico‐seconds. Our contribution to this project is to help with identification and efficient fabrication of novel electron emitting materials with properties optimized for use in such detectors. We have assembled several techniques into a single ultra‐high vacuum apparatus in order to enable characterization of both photocathode and secondary electron emission (SEE) materials. This apparatus will examine how photocathode quantum efficiency and SEE material electron yield correlate to surface chemical composition, state, and band structure. The techniques employed in this undertaking are X‐ray photoelectron spectroscopy (XPS) for surface chemical composition, ultraviolet photoelectron spectroscopy (UPS) for the determinati...