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Singer, W.

Paper Title Page
TPPT072 Effects of Electric and Magnetic Fields on the Performance of a Superconducting Cavity 3874
 
  • G. Ciovati, P. Kneisel
    Jefferson Lab, Newport News, Virginia
  • J.S. Sekutowicz, W. Singer
    DESY, Hamburg
 
  Funding: Work supported by the U.S. DOE Contract No DE-AC05-84ER40150.

A special two-cell cavity was designed to obtain surface field distributions suitable for investigation of electric and magnetic field effects on cavity performance. The cavity design and preliminary results were presented in a previous contribution. The bulk niobium cavity was heat-treated in a vacuum furnace at 1250C to improve the thermal conductivity. Three seamless hydroformed NbCu cavities of the same design were fabricated to investigate the role of the electron beam welds located in high field areas.

 
TPPT075 Influence of Ta Content in High Purity Niobium on Cavity Performance 3955
 
  • P. Kneisel, G. Ciovati, G. Myneni
    Jefferson Lab, Newport News, Virginia
  • T. Carneiro
    Reference Metals, Bridgeville, Pennsylvania
  • D. Proch, W. Singer, X. Singer
    DESY, Hamburg
 
  Funding: Work supported by the U.S. DOE Contract No DE-AC05-84ER40150.

In a previous paper* we have reported about initial tests of single cell 1500 MHz cavities made from high purity niobium with three different Ta contents of 160 ppm, ~600 ppm and ~1400 ppm. These cavities had been treated by buffered chemical polishing several times and 100 mm, 200 mm and 300 mm of material had been removed from the surfaces. This contribution reports about subsequent tests following post purification heat treatments with Ti and “in situ” baking. As a result, all cavities exhibited increased quench fields due to the improved thermal conductivity after the heat treatment. After the "in situ" baking at 120C for ~40 hrs the always present Q-drop at high fields disappeared and further improvements in accelerating gradient could be realized. Gradients as high as Eacc = 35 MV/m were achieved and there were no clear indications that the cavity performance was influenced by the Ta content in the material. A multi-cell cavity from the high Ta content material is being fabricated and results will be presented at this conference.

*P. Kneisel et al., Linac 2004.

 
FPAT078 Supporting Cavity Production Using an Engineering Data Management System 4024
 
  • J. Buerger, J.A. Dammann, L. Hagge, J.I. Iversen, A. Matheisen, W. Singer
    DESY, Hamburg
 
  The reliable production of superconducting cavities is an essential issue for any future accelerator applying the “cold” technology. At DESY the complex manufacturing process is supported by an engineering data management system (EDMS). During the mechanical manufacturing process many quality checks are performed and their results are documented in inspection sheets, which are stored in the system and used for controlling. The EDMS further controls the subsequent preparation process by automatically creating and issuing work instructions for the treatment of the surfaces of the cavities. In parallel the necessary documentation for quality assurance is generated. The documentation is linked to the product breakdown structure; this enables users to easily navigate from inspection sheets of selected components forward to their 3D CAD model as well as back to the results of the examination of the original niobium sheet. The poster presents the structural approach for the documentation using a commercially available EDMS. Supporting the lifecycle by electronic workflow techniques is described.