| Paper | Title | Page |
|---|---|---|
| WEPWI010 | Results from the First Single Cell Nb3Sn Cavity Coatings at JLab | 3509 |
|
||
|
Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. Nb3Sn is a promising superconducting material for SRF applications and has the potential to exceed the limitations of niobium. We have used the recently commissioned Nb3Sn coating system to investigate Nb3Sn coatings on several single cell cavities by applying the same coating procedure on several different single cells with different history and pre-coating surface preparation. We report on our findings with four 1.5 GHz CEBAF-shape single cell and one 1.3 GHz ILC-shape single cavities that were coated, inspected, and tested. |
||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWI010 | |
| Export • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | |
| WEPWI011 | Commissioning Results of Nb3Sn Cavity Vapor Diffusion Deposition System at JLab | 3512 |
|
||
|
Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. Nb3Sn as a BCS superconductors with a superconducting critical temperature higher than that of niobium offers potential benefit in lower surface resistance at the same temperature and frequency for SRF cavities. A Nb3Sn vapor diffusion deposition system was built and commissioned at Jefferson Lab. As the part of the commissioning a single cell 1.5 GHz CEBAF-shaped cavity was coated in the built system. The cavity exhibited the superconducting transition at about 17.9 K. The low field quality factor was about 5x109 at 4 K and 7x109 at 2 K dropping with field to about 109 at both temperatures at about 8 MV/m. |
||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWI011 | |
| Export • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | |
| WEPWI019 | Quench Studies of Six High Temperature Nitrogen Doped 9 Cell Cavities for Use in the LCLS-II Baseline Prototype Cryo-module at Jefferson Laboratory | 3528 |
|
||
|
Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. Jefferson Lab (JLab) processed six nine-cell cavities as part of a small-scale production for LCLS-II cavity processing development utilizing the promising nitrogen-doping process. [1] Various nitrogen-doping recipes have been scrutinized to optimize process parameters with the aim to guarantee an unloaded quality factor (Q 0) of 2.7·1010 at an accelerating field (Eacc) of 16 MV/m at 2.0 K in the cryomodule. During the R&D phase the characteristic Q0 vs. Eacc performance curve of the cavities has been measured in JLab’s vertical test area at 2 K. The findings showed the characteristic rise of the Q0 with Eacc as expected from nitrogen-doping. Initially, five cavities achieved an average Q0 of 3.3·1010 at the limiting Eacc averaging to 16.8 MV/m, while one cavity experienced an early quench accompanied by an unusual Q 0 vs. Eacc curve. The project accounts for a cavity performance loss from the vertical dewar test (with or without the helium vessel) to the horizontal performance in a cryomodule, such that these results leave no save margin to the cryomodule specification. Consequently, a refinement of the nitrogen-doping has been initiated to guarantee an average quench field above 20 MV/m without impeding the Q 0. This paper covers the refinement work performed for each cavity, which depends on the initial results, as well as a quench analysis carried out before and after the rework during the vertical RF tests as far as applicable. |
||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWI019 | |
| Export • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | |