11 September 2015 Review and present status of preparation of thin layer lead photocathodes for e- injectors of superconducting RF linacs
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Proceedings Volume 9662, Photonics Applications in Astronomy, Communications, Industry, and High-Energy Physics Experiments 2015; 966233 (2015) https://doi.org/10.1117/12.2205443
Event: XXXVI Symposium on Photonics Applications in Astronomy, Communications, Industry, and High-Energy Physics Experiments (Wilga 2015), 2015, Wilga, Poland
Abstract
Results are reported on using evaporation and UHV arc lead deposition to create thin-layer superconducting Pb photocathodes on niobium wall of electron gun. Evaporated photocathodes were prepared and tested for the first time in 2014. A complete XFEL-type photo-injector with an evaporated photocathode underwent successful quality check at DESY - an acceptable working point was reached. On the other hand poor adhesion to niobium proved to be the most serious shortcoming of the evaporated Pb layers. UHV arc deposition seems to be much more promising in this context as it allows energetic coating. Filtered arc coating lead to creation of uniform, 2 μm thick lead layers with casual spherical extrusions which enhance locally electric field and leads to high dark current. Conditioning in electric field is needed to reduce the field emission effects from these layers to acceptably low value. Using non-filtered UHV lead deposition enabled fast coating up to a thickness above 10 μm. Pb films obtained in this way require further post-processing in pulsed plasma ion beams in a rod plasma injector. In order to reach a sufficiently planar film surface the pulsed heat flow through a lead layer on niobium was modeled and computed.
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Jerzy Lorkiewicz, Jerzy Lorkiewicz, Robert Nietubyc, Robert Nietubyc, Jacek Sekutowicz, Jacek Sekutowicz, Marek Barlak, Marek Barlak, Denis Kostin, Denis Kostin, Anna Kosinska, Anna Kosinska, Roman Barday, Roman Barday, Rong Xiang, Rong Xiang, Robert Mirowski, Robert Mirowski, Wojciech Grabowski, Wojciech Grabowski, Jan Witkowski, Jan Witkowski, } "Review and present status of preparation of thin layer lead photocathodes for e- injectors of superconducting RF linacs", Proc. SPIE 9662, Photonics Applications in Astronomy, Communications, Industry, and High-Energy Physics Experiments 2015, 966233 (11 September 2015); doi: 10.1117/12.2205443; https://doi.org/10.1117/12.2205443
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