Photocathodes: Mapping, Controlled Porosity, Cesium, and Gold

dc.contributor.advisorO'Shea, Patrick Gen_US
dc.contributor.authorRiddick, Blake Cutleren_US
dc.contributor.departmentPhysicsen_US
dc.contributor.publisherDigital Repository at the University of Marylanden_US
dc.contributor.publisherUniversity of Maryland (College Park, Md.)en_US
dc.date.accessioned2014-02-12T06:31:00Z
dc.date.available2014-02-12T06:31:00Z
dc.date.issued2013en_US
dc.description.abstractPhotocathodes play a critical role in a large variety of applications, from detectors in medical imaging to electron beam sources for fundamental science. Via the photoelectric effect, photocathodes emit electrons in response to light of sufficient energy. Three important characteristics of photocathodes are quantum efficiency (the fraction of incident photons that generates emitted electrons), lifetime (how long the cathodes are operational), and emission uniformity. Coating a photocathode with an atomic layer of cesium dramatically improves quantum efficiency, but the inherent fragility of this layer worsens lifetime. The design and testing of a cesium rejuvenation system which prolongs lifetime will be presented, and a controlled porosity design which could improve emission uniformity will be discussed. A new method of mapping quantum efficiency will be presented. The initial results of testing cesium auride will be discussed, as they show the cathodes have surprisingly high quantum efficiency and the potential for very long lifetime.en_US
dc.identifier.urihttp://hdl.handle.net/1903/14944
dc.language.isoenen_US
dc.subject.pqcontrolledPhysicsen_US
dc.titlePhotocathodes: Mapping, Controlled Porosity, Cesium, and Golden_US
dc.typeDissertationen_US

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