Paper | Title | Page |
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TUPSM05 | Studies of Field and Photo-Emission in a New Short-Pulse, High-Charge Cs2Te RF Photocathode Gun | 637 |
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Funding: This work was funded by the U.S. Dept. of Energy Office of Science under contract number Agency DE-AC02-06CH11357. A new high-charge RF gun is now operating at the Argonne Wakefield Accelerator (AWA) facility at Argonne National Laboratory (ANL). The 1.5 cell 1.3 GHz gun uses a Cesium telluride photocathode driven with a 248 nm laser to provide short-pulse, high charge electron beams for the new 75 MeV drive beamline. The high-gradient RF gun (peak field on the cathode > 80MV/m) is a key piece of the facility upgrade (see M. E. Conde, this proceedings). The large Cs2Te photocathode (diameter > 30 mm) is fabricated in-house. The photo-injector generates high-charge, short pulse, single bunches (Q > 100 nC) or bunch-trains (Q > 1000 nC) for wakefield experiments, typically involving dielectric-loaded accelerating structures. Field-emitted dark current from the Cs2Te cathode was measured during RF conditioning. Fowler-Nordheim plots of the data are presented and compared to similar measurements made using a copper cathode in the initial phase of conditioning. Results of quantum efficiency (QE) studies are presented with the cathode operating in both single and bunch-train modes. |
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