SRF2017 - List of Authors (Gai, W.)

Paper	Title	Page
MOPB065	Development of Hybrid Superconducting Photocathodes on Niobium Using High QE Coatings	205
	M. Warren, A.R. Denchfield, N. Samuelson, J. Zasadzinski IIT, Chicago, Illinois, USA W. Gai, J.H. Shao, E.E. Wisniewski ANL, Argonne, Illinois, USA L.K. Spentzouris, Z.M. Yusof Illinois Institute of Technology, Chicago, Illinois, USA
	High power, low emittance electron beams require superconducting RF photoinjectors, typically made of pure Nb, and a superconducting photocathode is desired. However, superconductivity and high photocathode quantum efficiency (QE) are not compatible, e.g. QE for pure Nb is only 10^-5 at 260 nm wavelength. Here is presented the current status of the development of hybrid superconducting photocathodes by the deposition of thin films of a high QE metal or semiconductor on Nb. Nb plugs coated with 10-100 nm of Mg have been tested for adhesion and dark current under RF fields as high as 60MV/m. QE measurements show significant enhancements over Nb. In another test, ultra thin films of the high QE material Cs2Te deposited on Nb are reported. Using the standard deposition procedure, QE ~12% is found for films ~ 200Å. As the thickness is reduced QE maintains a high value ~ 6% for films as thin as 2.0 nm. These results are quite promising for future superconducting photocathodes.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB065
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Paper

Title

Page

Development of Hybrid Superconducting Photocathodes on Niobium Using High QE Coatings

205

M. Warren, A.R. Denchfield, N. Samuelson, J. Zasadzinski
IIT, Chicago, Illinois, USA
W. Gai, J.H. Shao, E.E. Wisniewski
ANL, Argonne, Illinois, USA
L.K. Spentzouris, Z.M. Yusof
Illinois Institute of Technology, Chicago, Illinois, USA

High power, low emittance electron beams require superconducting RF photoinjectors, typically made of pure Nb, and a superconducting photocathode is desired. However, superconductivity and high photocathode quantum efficiency (QE) are not compatible, e.g. QE for pure Nb is only 10^-5 at 260 nm wavelength. Here is presented the current status of the development of hybrid superconducting photocathodes by the deposition of thin films of a high QE metal or semiconductor on Nb. Nb plugs coated with 10-100 nm of Mg have been tested for adhesion and dark current under RF fields as high as 60MV/m. QE measurements show significant enhancements over Nb. In another test, ultra thin films of the high QE material Cs2Te deposited on Nb are reported. Using the standard deposition procedure, QE ~12% is found for films ~ 200Å. As the thickness is reduced QE maintains a high value ~ 6% for films as thin as 2.0 nm. These results are quite promising for future superconducting photocathodes.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB065

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)