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Title |
Page |
| MOPLT151 |
Study of Arc-related RF Faults in the CEBAF Cryomodules
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890 |
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- E. Daly, D. Curry, J. Musson, G. Myneni, T. Powers, H. Wang, T.E. Whitlatch
Jefferson Lab, Newport News, Virginia
- I.E. Campisi
ORNL/SNS, Oak Ridge, Tennessee
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A series of measurements has been conducted on two superconducting radio-frequency cavity pairs, installed in cryomodules and routinely operated in the Continuous Electron Beam Accelerator Facility, in order to study the RF-vacuum interaction during an RF fault. These arc-related fault rates increase with increasing machine energy, contribute to system downtime and directly affect the accelerator?s availability. For this study, the fundamental power coupler waveguides have been instrumented with vacuum gauges, additional arc detectors, additional infrared sensors and temperature sensors in order to measure the system response during both steady-state operations and RF fault conditions. Residual gas analyzers have been installed on the waveguide vacuum manifolds to monitor the gas species present during cooldown, RF processing and operation. Simultaneous measurements of the signals are presented, a comparison with analysis is shown and results are discussed. The goal of this study is to characterize the RF-vacuum interaction during normal operations. With a better understanding of the installed system response, methods for reducing the fault rate may be devised, ultimately leading to improvements in availability.
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| TUPKF074 |
Niobium Thin Film Cavity Deposition by ECR Plasma
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1108 |
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- A-M. Valente, H.L. Phillips, H. Wang, A. Wu, G. Wu
Jefferson Lab, Newport News, Virginia
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Nb/Cu technology for superconducting cavities has proven to be over the years a viable alternative to bulk niobium. Energetic vacuum deposition is a very unique alternative method to grow niobium thin film on copper. Single crystal growth of niobium on sapphire substrate has been achieved as well as good surface morphology of niobium on small copper samples. The design of a cavity deposition system is in development. This paper presents the exploratory studies of the influence of the deposition energy on the Nb thin film properties. Several possible venues to achieve Nb/Cu cavity deposition with this technique are also discussed along with the design of the cavity deposition setup under development.
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| TUPKF072 |
Production and Performance of the CEBAF Upgrade Cryomodule Intermediate Prototypes
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1105 |
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- A-M. Valente, E. Daly, J.R. Delayen, M. Drury, R. Hicks, C. Hovater, J. Mammosser, H.L. Phillips, T. Powers, J.P. Preble, C. Reece, R.A. Rimmer, H. Wang
Jefferson Lab, Newport News, Virginia
- C. Thomas-Madec
SOLEIL, Gif-sur-Yvette
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We have installed two new cryomodules, one in the nuclear physics accelerator (CEBAF) and the other in the Free Electron Laser (FEL) of Jefferson Lab. The new cryomodules consist of 7-cell cavities with the original CEBAF cell shape and were designed to deliver gradients of 70 MV/module. Several significant design innovations were demonstrated in these cryomodules. This paper describes the production procedures, the performance characteristics of these cavities in vertical tests, results of tests in the new cryomodule test facility (CMTF) as well as the commissioning in the CEBAF tunnel and FEL. Performances and limitations after installation in the accelerators are discussed in this paper along with improvements proposed for future cryomodules.
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